软件开发中英文对照外文翻译文献

毕业设计（论文）外文文献翻译文献、资料中文题目：软件开发概念和设计方法文献、资料英文题目：文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：班级：姓名：学号：指导教师：翻译日期： 2017.02.14外文资料原文Software Development Concepts and DesignMethodologiesDuring the 1960s, ma inframes and higher level programming languages were applied to man y problems including human resource s yste ms,reservation s yste ms, and manufacturing s yste ms. Computers and software were seen as the cure all for man y bu siness issues were some times applied blindly. S yste ms sometimes failed to solve the problem for which the y were designed for man y reasons including:•Inability to sufficiently understand complex problems•Not sufficiently taking into account end-u ser needs, the organizational environ ment, and performance tradeoffs•Inability to accurately estimate development time and operational costs •Lack of framework for consistent and regular customer communications At this time, the concept of structured programming, top-down design, stepwise refinement，and modularity e merged. Structured programming is still the most dominant approach to software engineering and is still evo lving. These failures led to the concept of "software engineering" based upon the idea that an engineering-like discipl ine could be applied to software design and develop ment.Software design is a process where the software designer applies techniques and principles to produce a conceptual model that de scribes and defines a solution to a problem. In the beginning, this des ign process has not been well structured and the model does not alwa ys accurately represent the problem of software development. However,design methodologies have been evolving to accommo date changes in technolog y coupled with our increased understanding of development processes.Whereas early desig n methods addressed specific aspects of thedevelop ment process, current methods atte mpt to address the entire scope of software development. Software design methods are often classified in reference to the peri od in which the y were introduced and the problems at that time. Driven b y coding and testing problems, tools and methods were developed. Early methods focused on modularity a nd top-down development, and information hiding through abstraction. This led to t he development of structured languages, structured analysis, and data flow analysis.In the last decade or so, the expense involved in automation has shifted from hardware to people. Therefore, the software engineering community has been focused on object oriented (O-O) design and the concept of re-usable code in order to reduce the human cost component. Inefficient designs and develop ment methodologies have been addressed with Computer Aided Software Engineering (CASE) tools, and fourth generation design l anguages. This has been done in an attempt replace the traditional waterf all life c ycle process model under which most existing software has been developed.一、Software Design FundamentalsSoftware design meth ods all aim to provide the software designer wi th a s yste m blueprint. This blueprint usually has three aspects: data, architectural, and procedural.•Data design refers to the data's organization, relationships, access and processing methods.•Architectural design defines the components of the sys tem a nd their relationships.•Procedural design builds on the data and architectural design phases to describe the processing details of the s yste m.Even though there are numerous design methodologies, their basic concepts are ver y similar-All software design methods partition the problem and software into smaller pieces in order to reduce complexity. They all strive to identif y data structures and functions, and provide measur ements for software quality. Some of the common principles in software design include: stepwise refinement, s oftware architecture, program structure, data structure,software procedures, mo d u la r i t y,a b s tr a c t io n,a n d in f o r ma t io n h i d i n g.二、M o d e r n D e s i g n M e t h o d o l o g i e sC o n ve n t io n a l s o f t wa r e d e ve l o p me n t p r a c t ic e s c a n g e n e r a l l y b ema p p e d o n to t h e tr a d i t io n a l l i f e-c y c l e p h a s e s o f a n a l ys i s,f u n c t i o n a ls p e c i f i c a t i o n,d e s i g n,i mp l e me n t a t i o n,t e s t i n g,a n d m a i n t e n a n c e.T h i st h o u g h t p r o c e s s i s i n a d e q u a t e f o r t o d a y's c o m p l e x i n f o r m a t i o n s y s t e m s.As the demand for software is growing much faster than the number of developers, adhering to conventional techniques such as the waterfall method requires too much time, too many people, and is difficult to ma nage. Hence, many new software development technologies have arisen. N e wl y d e ve lo p e d p r a c tic e s a n d mo d e ls d o n o t a tte mp t to s e p a r a te p h a s e s o f s o f twa r e development, such as specification and implementation, but instead focus on the concept of program transformation through stepwise refinement and iteration.1、O b j e c t-O r i e n t e d Te c h n o l o g yObject-Oriented (O-O) software design technology is fundamentally different from the traditional methods described above. With traditional methods, each module is recognized a major step in the overall process and the process goes from one step to the next. On the other hand, O-O design is structured around a model of objects and the functions they perform.O-O programming can be traced to the simulation language SIMULA, a hig h level language developed in the late 60's that introduced object classes as a method to encapsulate data. Later, in the 1970s, Smalltalk was introduced as a complete grapgh design and coding as detail is added to the design. This provides a common language throughout each stage in development. O-O is best applied with specifically designed O-O development tools, but it is important to remember that as a methodology is it not specific to any programming language. Many different programming languages can be used to implement 0-0 technology and design methodologies.Instead of procedures and functions passing data back and forth, in object oriented design, the system is viewed as a collection of objects with messages passed from object to object. Each object has its own set of associated operations.Object-oriented design is based on the idea of information hiding and modularization of both data and processing. It is best used when neither data structure nor processing operations are well defined ahead of time. This is quite useful in today's business environment where requirements are always changing and not very well defined. Thus, it has become quite popular! The concept of objects performing services is a natural way of thinking for both developers and customers. This facilitates understanding the problem domain and a more natural design. In addition, there are many benefits of object-oriented development. These include:•I n h e r i t a n c e c a p i t a l i z e s o n t h e c o m m o n a l t y o f a t t r i b u t e s a n d s e r v i c e s a l l o w i n g c o d e a n d objects to be re-used..I n f o r m a t i o n h i d i n g m a k e s s y s t e m s m o r e s t a b l e b y l o c a l i z i n g c h a n g e s t o o b j e c t s a n d t h e r e b y m a k i n g t h e m r e u s a b l e..T h e o b j e c t-o r i e n t e d d e v e l o p m e n t p r o c e s s i s c o n s i s t e n t f r o m a n a l y s i s,t h r o u g h d e s i g n, t o c o d i n g.More information on Object Oriented Programming principles can be found in Chapter 4-Organization of Programming Languages and Programming Concepts.2、P r o t o t y p i n gPrototyping was invented because end users participating in the development phase found it difficult to understand requirement specifications and conceptual models. However, when it first began being used in the 1980s, most conventional life c ycle developers considered it expensive and time consuming.S i n c e t h a t t i m e,u s e r s a n d d e v e l o p e r s h a v e u s e d p r o t o t y p e s s u c c e s s f u l l y a s a communications tool to demonstrate system requirements. After several prototype iterations, developers have a better understanding of user requirements and users have a better idea of how the system will eventually work, look, and l.T h e n u mb e r o f t i me s th e p r o to t yp e is in c r e me n t a l l y r e f in e d d e p e n d s o n h o w we l l th e u s e r r e q u i r e me n ts a n d u n d e r s t o o d.I t a ls o d e p e n d s o n th e u s e r s n e e d to a d d r e q u ir e me n ts o r c h a n g e p r e v i o u s l y s t a t e d r e q u i r e m e n t s.A f t e re s t a b l i s h i n g a n o v e r a l l a r c h i t e c t u r e a n df r a me w o r k, t h e s ys t e m i s d e v e l o p e d a n d d e l i v e r e d in in c r e me n ts.U s e r s ma y e x p e r i me n t w i t h a n d u s e d e l i v e r e d i n c r e me n t s w h i l e o t h e r s a r e b e i ng d e v e l o p e d.Fo r i n s t a n c e,th e fi r s t p r o t o t yp e ma y b e d e l i v e r e d t h a t i m p l e m e n t s a c e r t a i n s c r e e n w i t h o n l y s o m e a c t i v e m e n u i t e m s.W h i l e u s e r s a r e e x p e r i me n t i n g w i t h t h i s s c r e e n a n d me n u i t e ms,o t h e r s c r e e n s a n d me n u i t e ms a r e c o n c u r r e n t l y b e in gd e v e l o p e d wh i c h la t e r w il l b e c o mb in e d w i th th e e x is t in g p r o to t yp e a s ite vo l v e s.O n c e t h e u s e r i s s a t i s f i e d t h a t t h e p r o t o t y p e m e e t s r e q u i r e m e n t s,t h e p r o t o t y p e i s t r a n s f o r me d i n to th e"s ys t e m".T h i s e ff o r t d e p e n d s o n s e v e r a l f a c to r s. I t ma y i n c lu d e a d d i n g f u n c t i o n a l i t y t h a t w a s n't i n i t i a l l y r e c o g n i z e d a s r e q u i r e d,r e p l a c i n g i n e f f i c i e n t p a r t s o f t h e p r o t o t yp e t o me e t p e r f o r ma n c e c r i t e r i a,o r a d a p t i n g t h e p r o t o t yp e t o f i t t h e u s e r's h a r d w a r e e n vi r o n me n t.P r o t o t y p i n g c a n b e g i n v e r y e a r l y, a f t e r s o m e p r e l i m i n a r y r e q u i r e m e n t s a n a l y s i s h a s d e t e r m i n e d t h e b a s i c f u n c t i o n a l i t y,s c o p e,a n d e n v i r o n m e n t o f t h e p r o p o s e d s o f t w a r e.C o n t r a r y t o t h e t r a d i t i o n a l w a t e r f a l l me t h o d,i n t h e p r o t o t yp i n g,f u n c t i o n a l s p e c i f i c a t i o n s a r e n o t f i x e d.R a t h e r,u s e r s a r e e n c o u r a g e d t o m o d i f y t h e i r r e q u i r e m e n t s a s t h e y t h e m s e l v e s b e g i n t o u n d e r s t a n d t h e m b e t t e r.T h i s i s b e c a u s e u s e r s o f t e n d o n't r e a l l y k n o w w h a t t h e y w a n t u n t i l t h e y s e e i t o n t h e s c r e e n.T h e p r o t o t yp i n g p r o c e s s o f d e mo n s t r a t i o n,r e v i e w,a n d r e f i n e me n t g e t s t h e u s e r m o r e i n v o l v e d i n t h e d e v e l o p m e n t p r o c e s s,g i v i n g t h e m a s e n s e o f o w n e r s h i p d u r i n g t h e p r o c e s s a n d a t f i n a l s y s t e m d e l i v e r y.H o w e v e r,d u e t o t h e m i n d s e t o f"p r o t o t y p e", u s e r s o f t e n f in d i t d iff ic u l t to ve r if y t h a t th e p r o to t yp e s a tis f ie s th e ir r e q u ir e me n ts. T h e r e f o r e, g u id e l in e s mu s t b e e s t a b l i s h e d t o d e te r m in e wh e n t o s to p i te r a t in g a n d th e p r o to t yp e to f in a l p r o d u c t.。

Java and the InternetIf Java is, in fact，yet another computer programming language，you may question why it is so important and why it is being promoted as a revolutionary step in computer programming。

The answer isn’t immediately obvious if you’re comin g from a traditional programming perspective。

Although Java is very useful for solving traditional stand-alone programming problems，it is also important because it will solve programming problems on the World Wide Web。

1.Client-side programmingThe Web’s in itial server—browser design provided for interactive content, but the interactivity was completely provided by the server. The server produced static pages for the client browser, which would simply interpret and display them。

Basic HTML contains simple mechanisms for data gathering: text—entry boxes, check boxes, radio boxes, lists and drop-down lists，as well as a button that can only be programmed to reset the data on the form or “submit” the data on the form back to the server。

中英文对照外文翻译(文档含英文原文和中文翻译)Application FundamentalsAndroid applications are written in the Java programming language. The compiled Java code — along with any data and resource files required by the application — is bundled by the aapt tool into an Android package, an archive file marked by an .apk suffix. This file is the vehicle for distributing the application and installing it on mobile devices; it's the file users download to their devices. All the code in a single .apk file is considered to be one application.In many ways, each Android application lives in its own world:1. By default, every application runs in its own Linux process. Android starts the process when any of the application's code needs to be executed, and shuts down the process when it's no longer needed and system resources are required by other applications.2. Each process has its own virtual machine (VM), so application code runs in isolation from the code of all other applications.3. By default, each application is assigned a unique Linux user ID. Permissions are set so that the application's files are visible only to that user and only to the application itself — although there are ways to export them to other applications as well.It's possible to arrange for two applications to share the same user ID, in which case they will be able to see each other's files. To conserve system resources, applications with the same ID can also arrange to run in the same Linux process, sharing the sameVM.Application ComponentsA central feature of Android is that one application can make use of elements of other applications (provided those applications permit it). For example, if your application needs to display a scrolling list of images and another application has developed a suitable scroller and made it available to others, you can call upon that scroller to do the work, rather than develop your own. Your application doesn't incorporate the code of the other application or link to it. Rather, it simply starts up that piece of the other application when the need arises.For this to work, the system must be able to start an application process when any part of it is needed, and instantiate the Java objects for that part. Therefore, unlike applications on most other systems, Android applications don't have a single entry point for everything in the application (no main() function, for example). Rather, they have essential components that the system can instantiate and run as needed. There are four types of components:ActivitiesAn activity presents a visual user interface for one focused endeavor the user can undertake. For example, an activity might present a list of menu items users can choose from or it might display photographs along with their captions. A text messaging application might have one activity that shows a list of contacts to send messages to, a second activity to write the message to the chosen contact, and other activities to review old messages or change settings. Though they work together to form a cohesive user interface, each activity is independent of the others. Each one is implemented as a subclass of the Activity base class.An application might consist of just one activity or, like the text messaging application just mentioned, it may contain several. What the activities are, and how many there are depends, of course, on the application and its design. Typically, one of the activities is marked as the first one that should be presented to the user when the application is launched. Moving from one activity to another is accomplished by having the current activity start the next one.Each activity is given a default window to draw in. Typically, the window fills the screen, but it might be smaller than the screen and float on top of other windows. An activity can also make use of additional windows — for example, a pop-up dialog that calls for a user response in the midst of the activity, or a window that presents users with vital information when they select a particular item on-screen.The visual content of the window is provided by a hierarchy of views — objects derived from the base View class. Each view controls a particular rectangular space within the window. Parent views contain and organize the layout of their children. Leaf views (those at the bottom of the hierarchy) draw in the rectangles they control and respond to user actions directed at that space. Thus, views are where the activity's interaction with the user takes place.For example, a view might display a small image and initiate an action when the user taps that image. Android has a number of ready-made views that you can use —including buttons, text fields, scroll bars, menu items, check boxes, and more.A view hierarchy is placed within an activity's window by theActivity.setContentView() method. The content view is the View object at the root of the hierarchy. (See the separate User Interface document for more information on views and the hierarchy.)ServicesA service doesn't have a visual user interface, but rather runs in the background for an indefinite period of time. For example, a service might play background music as the user attends to other matters, or it might fetch data over the network or calculate something and provide the result to activities that need it. Each service extends the Service base class.A prime example is a media player playing songs from a play list. The player application would probably have one or more activities that allow the user to choose songs and start playing them. However, the music playback itself would not be handled by an activity because users will expect the music to keep playing even after they leave the player and begin something different. To keep the music going, the media player activity could start a service to run in the background. The system would then keep the music playback service running even after the activity that started it leaves the screen.It's possible to connect to (bind to) an ongoing service (and start the service if it's not already running). While connected, you can communicate with the service through an interface that the service exposes. For the music service, this interface might allow users to pause, rewind, stop, and restart the playback.Like activities and the other components, services run in the main thread of the application process. So that they won't block other components or the user interface, they often spawn another thread for time-consuming tasks (like music playback). See Processes and Threads, later.Broadcast receiversA broadcast receiver is a component that does nothing but receive and react to broadcast announcements. Many broadcasts originate in system code — for example, announcements that the timezone has changed, that the battery is low, that a picture has been taken, or that the user changed a language preference. Applications can also initiate broadcasts — for example, to let other applications know that some data has been downloaded to the device and is available for them to use.An application can have any number of broadcast receivers to respond to any announcements it considers important. All receivers extend the BroadcastReceiver base class.Broadcast receivers do not display a user interface. However, they may start an activity in response to the information they receive, or they may use the NotificationManager to alert the user. Notifications can get the user's attention in various ways — flashing the backlight, vibrating the device, playing a sound, and so on. They typically place a persistent icon in the status bar, which users can open to get the message.Content providersA content provider makes a specific set of the application's data available to other applications. The data can be stored in the file system, in an SQLite database, or in anyother manner that makes sense. The content provider extends the ContentProvider base class to implement a standard set of methods that enable other applications to retrieve and store data of the type it controls. However, applications do not call these methods directly. Rather they use a ContentResolver object and call its methods instead. A ContentResolver can talk to any content provider; it cooperates with the provider to manage any interprocess communication that's involved.See the separate Content Providers document for more information on using content providers.Whenever there's a request that should be handled by a particular component, Android makes sure that the application process of the component is running, starting it if necessary, and that an appropriate instance of the component is available, creating the instance if necessary.Activating components: intentsContent providers are activated when they're targeted by a request from a ContentResolver. The other three components — activities, services, and broadcast receivers — are activated by asynchronous messages called intents. An intent is an Intent object that holds the content of the message. For activities and services, it names the action being requested and specifies the URI of the data to act on, among other things. For example, it might convey a request for an activity to present an image to the user or let the user edit some text. For broadcast receivers, theIntent object names the action being announced. For example, it might announce to interested parties that the camera button has been pressed.There are separate methods for activating each type of component:1. An activity is launched (or given something new to do) by passing an Intent object toContext.startActivity() or Activity.startActivityForResult(). The responding activity can look at the initial intent that caused it to be launched by calling its getIntent() method. Android calls the activity's onNewIntent() method to pass it any subsequent intents. One activity often starts the next one. If it expects a result back from the activity it's starting, it calls startActivityForResult() instead of startActivity(). For example, if it starts an activity that lets the user pick a photo, it might expect to be returned the chosen photo. The result is returned in an Intent object that's passed to the calling activity's onActivityResult() method.2. A service is started (or new instructions are given to an ongoing service) by passing an Intent object to Context.startService(). Android calls the service's onStart() method and passes it the Intent object. Similarly, an intent can be passed to Context.bindService() to establish an ongoing connection between the calling component and a target service. The service receives the Intent object in an onBind() call. (If the service is not already running, bindService() can optionally start it.) For example, an activity might establish a connection with the music playback service mentioned earlier so that it can provide the user with the means (a user interface) for controlling the playback. The activity would call bindService() to set up that connection, and then call methods defined by the service to affect the playback.A later section, Remote procedure calls, has more details about binding to a service.3. An application can initiate a broadcast by passing an Intent object to methods like Context.sendBroadcast(), Context.sendOrderedBroadcast(), andContext.sendStickyBroadcast() in any of their variations.Android delivers the intent to all interested broadcast receivers by calling their onReceive() methods. For more on intent messages, see the separate article, Intents and Intent Filters.Shutting down componentsA content provider is active only while it's responding to a request from a ContentResolver. And a broadcast receiver is active only while it's responding to a broadcast message. So there's no need to explicitly shut down these components. Activities, on the other hand, provide the user interface. They're in a long-running conversation with the user and may remain active, even when idle, as long as the conversation continues. Similarly, services may also remain running for a long time. So Android has methods to shut down activities and services in an orderly way:1. An activity can be shut down by calling its finish() method. One activity can shut down another activity (one it started with startActivityForResult()) by calling finishActivity().2. A service can be stopped by calling its stopSelf() method, or by calling Context.stopService().Components might also be shut down by the system when they are no longer being used or when Android must reclaim memory for more active components. A later section, Component Lifecycles, discusses this possibility and its ramifications in more detail.The manifest fileBefore Android can start an application component, it must learn that the component exists. Therefore, applications declare their components in a manifest file that's bundled into the Android package, the .apk file that also holds the application's code, files, and resources.The manifest is a structured XML file and is always named AndroidManifest.xml for all applications. It does a number of things in addition to declaring the application's components, such as naming any libraries the application needs to be linked against (besides the default Android library) and identifying any permissions the application expects to be granted.But the principal task of the manifest is to inform Android about the application's components. For example, an activity might be declared as follows:The name attribute of the <activity> element names the Activity subclass that implements the activity. The icon and label attributes point to resource files containing an icon and label that can be displayed to users to represent the activity.The other components are declared in a similar way — <service> elements for services, <receiver> elements for broadcast receivers, and <provider> elements for content providers. Activities, services, and content providers that are not declared in the manifest are not visible to the system and are consequently never run. However, broadcast receivers can either be declared in the manifest, or they can be created dynamically in code (as BroadcastReceiver objects) and registered with the system by calling Context.registerReceiver().For more on how to structure a manifest file for your application, see The Android Manifest.xml File.Intent filtersAn Intent object can explicitly name a target component. If it does, Android finds that component (based on the declarations in the manifest file) and activates it. But if a target is not explicitly named, Android must locate the best component to respond to the intent. It does so by comparing the Intent object to the intent filters of potential targets. A component's intent filters inform Android of the kinds of intents the component is able to handle. Like other essential information about the component, they're declared in the manifest file. Here's an extension of the previous example that adds two intent filters to the activity:The first filter in the example — the combination of the action"android.intent.action.MAIN" and the category"UNCHER" — is a common one. It marks the activity as one that should be represented in the application launcher, the screen listing applications users can launch on the device. In other words, the activity is the entry point for the application, the initial one users would see when they choose the application in the launcher.The second filter declares an action that the activity can perform on a particular type of data.A component can have any number of intent filters, each one declaring a different set of capabilities. If it doesn't have any filters, it can be activated only by intents that explicitly name the component as the target.For a broadcast receiver that's created and registered in code, the intent filter is instantiated directly as an IntentFilter object. All other filters are set up in the manifest. For more on intent filters, see a separate document, Intents and Intent Filters.应用程序基础Android DevelopersAndroid应用程序使用Java编程语言开发。

外文文献资料1、Software EngineeringSoftware is the sequences of instructions in one or more programming languages that comprise a computer application to automate some business function. Engineering is the use of tools and techniques in problem solving. Putting the two words together, software engineering is the systemtic application of tools and techniques in the development of computer-based applications.The software engineering process describes the steps it takes to deelop the system. We begin a development project with the notion that there is a problem to be solved via automation. The process is how you get from problem recognition to a working solution. A quality process is desirable because it is more likely to lead to a quality product. The process followed by a project team during the development life cycle of an application should be orderly, goal-oriented, enjoyable, and a learning experience.Object-oriented methodology is an approach to system lifecycle development that takes a top-down view of data objects, their allowable actions, and the underlying communication requirement to define a system architecture. The data and action components are encapsulated, t hat is , they are combined together, to form abstract data types Encapsulation means that if I know what data I want ,I also know the allowable processes against that data. Data are designed as lattice hierarchies of relationships to ensure that top-down, hierarchic inheritance and side ways relationships are accommodated. Encapsulated objects are constrained only to communicate via messages. At a minimum, messages indicate the receiver and action requested. Messages may be more elaborate, including the sender and data to be acted upon.That we try to apply engineering discipline to software development does not mean that we have all the answers about how to build applications. On the contrary,we still build systems that are not useful and thus are not used. Part of the reason for continuing problems in application development, is that we are constantly trying to hita moving target. Both the technology and the type of applications needed by businesses are constantly changing and becoming more complex. Our ability todevelop and disseminate knowledge about how to successfully build systems for new technologies and new application types seriously lags behind technological andbusiness changes.Another reason for continuing problems in application development is that wefromaren’t always free to do what we like and it is hard to change habits and culturesthe old way of doing things, as well as get users to agree with a new sequence o fevents or an unfamiliar format for documentation.You might ask then, if many organizations don’t use good software engineering practices, why should I bother learning them? There are two good answers to thisquestion. First, if you never know the right thing to do, you have no chance of everusing it. Second, organizations will frequently accept evolutionary, small steps ofchange instead of revolutionary, massive change. You can learn individual techniquesthat can be applied without complete devotion to one way of developing systems. Inthis way, software engineering can speed changee in their organizations by demonstrating how the tools and techniques enhance t h quality of both the productand the process of building a system.2、Data Base System1、IntroductionThe development of corporate databases w ill be one of the most importantdata-processing activities for the rest of the 1970s. Date will be increasingly regardedas a vital corporate resource, which must be organized so as to maximize their value.In addition to the databases within an organization, a vast new demand is growing fordatabase services, which will collect, organize, and sell data.The files of data which computers can use are growing at a staggering rate. Thegrowth rate in the size of computer storage is greater than the growth in the size orpower of any other component in the exploding data processing industry. The moredata the computers have access to, the greater is their potential power. In all walks oflife and in all areas of industry, data banks will change the areas of what it is possiblefor man to do. In the end of this century, historians will look back to the coming of computer data banks and their associated facilities as a step which changed the nature of the evolution of society, perhaps eventually having a greater effect on the human condition than even the invention of the printing press.Some most impressive corporate growth stories of the generation are largely attributable to the explosive growth in the need of information.The vast majority of this information is not yet computerized. However, the costof data storage hardware is dropping more rapidly than other costs in data processing. It will become cheaper to store data on computer files than to store them on paper. Not only printed information will be stored. The computer industry is improving its capability to store line drawing, data in facsimile form, photo-graphs, human speech, etc. In fact, any form of information other than the most intimate communications between humans can be transmitted and stored digitally.There are two main technology developments likely to become available in the near future. First, there are electromagnetic devices that will hold much more data than disks but have much longer access time. Second, there are solid-state technologies that will give microsecond access t ime but capacities are smaller than disks.Disks themselves may be increased in capacity somewhat. For the longer term future there are a number of new technologies which are currently working in research labs which may replace disks and may provide very large microsecond-access-time d evices. A steady stream of new storage devices is thus likely to reach the marketplace over the next 5 years, rapidly lowering the cost of storing data.Given the available technologies, it is likely that on-line data bases will use twoor three levels of storage. One solid-state with microsecond access time, one electromagnetic with access time of a fraction of a second. If two ,three ,or four levels of storage are used, physical storage organization will become more complex ,probably with paging mechanisms to move data between the levels; solid-state storage offers the possibility of parallel search operation and associativememory.Both the quantity of data stored and the complexity of their organization are going up by leaps and bounds. The first trillion bit on-line stores are now in use . in a time ,stores of this size may be common.few year’ｓA particularly important consideration in data base design is to store the data so that the can be used for a wide variety of applications and so that the way they can be changed quickly and easily. On computer installation prior to the data base era it has been remarkably difficult to change the way data are used. Different programmers view the data in different ways and constantly want to modify them as new needs arise modification , however ,can set off a chain reaction of changes to existing programs and hence can be exceedingly expensive to accomplish .Consequently , data processing has tended to become frozen into its old data structures .To achieve flexibility of data usage that is essential in most commercial situations . Two aspects of data base design are important. First, it should be possible to interrogate and search the data base without the lengthy operation of writing programs in conventional programming languages. Second ,the data should be independent of the programs which use them so that they can be added to or restructured without the programs being changed .The work of designing a data base is becoming increasing difficult , especially if it is to perform in an optimal fashion . There are many different ways in which data can be structured ,and they have different types of data need to be organized in different ways. Different data have different characteristics , which ought to effect the data organization ,and different users have fundamentally different requirements. So we need a kind of data base management system(DBMS)to manage data.Data base design using the entity-relationship model begins with a list of the entity types involved and the relationships among them. The philosophy of assuming that the designer knows what the entity types are at the outset is significantly different from the philosophy behind the normalization-based approach.The entity-relationship(E-R)approach uses entity-relationship diagrams. The E-Rapproach requires several steps to produre a structure that is acceptable by the particular DBMS. These steps are:(1) Data analysis(2) Producing and optimizing the entity model.(3) Logical schema development(4) Physical data base design process.Developing a data base structure from user requirements is called data bases design. Most practitioners agree that there are two separate p hases t o the data base design process. The design of a logical database structure that is processable by theview of data, and is the data base management s ystem(DBMS)describes the user’sselection of a physical structure such as the indexed sequential or direct access method of the intended DBMS.Current data base design technology shows many residual effects of its outgrowth from single-record file design methods. File design is primarily application program dependent since the data has been defined and structured in terms of individual applications to use them. The advent of DBMS revised the emphasis in data and program design approaches.There are many interlocking questions in the design of data-base s ystems and many types of technique that one can use is answer to the question so many; in fact, that one often sees valuable approaches being overlooked in the design and vital questions not being asked.There will soon be new storage devices, new software techniques, and new types of data bases. The details will change, but most of the principles will remain. Therefore, the reader should concentrate on the principles.2、Data base systemThe conception used for describing files and data bases has varied substantially in the same organization.A data base may be defined as a collection of interrelated data stored together with as little redundancy as possible to serve on or more applications in an optimal fashion; the data are stored so that they are independent of programs which use thedata; a common and controlled approach is used in adding new data and in modifying and retrieving existing data within the data base. One system is said to contain a collection of data bases if they are entirely separate in structure.A data base may be designed for batch processing, real-time processing, orin-line processing. A data base system involve application program, DBMS, and data base.One of the most important characteristics of most data bases i s that they will constantly need to change and grow. Easy restructuring of the data base must be possible as new data types and new applications are added. The restructuring should be possible without having to rewrite the application program and in general should cause as little upheaval as possible. The ease with which a data base can be changed will have a major effect on the rate at which data-processing a pplication can be developed in a corporation.The term data independence is often quoted as being one of the main attributes of a data base. It implies that the data and the application programs which use them are independent so that either may be changed without changing the other. When a single set of data items serves a variety of applications, different application programs perceive different relationships between the data items. To a large extent, data-base organization is concerned with the representation of relationship between data items and records as well as how and where the data are stored. A data base used for many applications can have multiple interconnections between the data item about which we may wish to record. It can describes the real world. The data item represents an attribute, and the attribute must be associated with the relevant entity. We design values to the attributes, one attribute has a special significance in that it identifies the entity.An attribute or set of attribute which the computer uses to identify a record or tuple is referred to as a key. The primary key is defined as that key used to uniquely identify one record or tuple. The primary key is of great importance because it is used by the computer in locating the record or tuple by means of an index or addressing algorithm.If the function of a data base were merely to store data, its organization would be simple. Most of the complexities arise from the fact that is must also show the relationships between the various items of data that are stored. It is different to describe the data in logical or physical.The logical data base description is referred to as a schema .A schema is a chart of the types of data that one used. It gives the names of the entities and attributes, and specifics the relations between them. It is a framework into which the values of the data-items can be fitted.We must distinguish between a record type and a instance of the record. Whenthis is really a record type. There are no data we talk about a ―personnel record‖,values associated with it.The term schema is used to mean an overall chart of all of the dataitem types and record types stored in a data he uses. Many different subschema can be derived from one schema.The schema and the subschema are both used by the data-base management system, the primary function of which is to serve the application programs by executing their data operations.A DBMS will usually be handing multiple data calls concurrently. It must organize its system buffers so that different data operations can be in process together. It provides a data definition language to specify the conceptual schema and most likely, some of the details regarding the implementation of the conceptual schema by the physical schema. The data definition language is a high-level language, enabling one to describe the conceptual schema in terms of a ―data model‖．The choice of a data model is a difficult one, since it must be rich enough in structure to describe significant aspects of the real world, yet it must be possible to determine fairly automatically an efficient implementation of the conceptual schemaby a physical schema. It should be emphasized that while a DBMS might be used to build small data bases, many data bases involve millions of bytes, and an inefficient implementation can be disastrous.We will discuss the data model in the following.3、Three Data ModelsLogical schemas are defined as data models with the underlying structure of particular database management systems superimposed on them. At the present time, there are three main underlying structures for database management systems. These are :RelationalHierarchicalNetworkThe hierarchical and network structures have been used for DBMS since the 1960s. The relational structure was introduced in the early 1970s.In the relational model, the entities and their relationships are represented b y two-dimensional tables. Every table represents an entity and is made up of rows and columns. Relationships between entities are represented by common columns containing identical values from a domain or range of possible values.The last user is presented with a simple data model. His and her request are formulated in terms of the information content and do not reflect any complexities due to system-oriented aspects. A relational data model is what the user sees, but it is not necessarily what will be implemented physically.The relational data model removes the details of storage structure and access strategy from the user interface. The model provides a relatively higher degree of data. To be able to make use of this property of the relational data model however, the design of the relations must be complete and accurate.Although some DBMS based on the relational data model are commercially available today, it is difficult to provide a complete set of operational capabilities with required efficiency on a large scale. It appears today that technological improvements in providing faster and more reliable hardware may answer the question positively.The hierarchical data model is based on a tree-like structure made up of nodes and branches. A node is a collection of data attributes describing the entity at that point.The highest node of the hierarchical tree structure is called a root. The nodes at succeeding lower levels are called children .A hierarchical data model always starts with a root node. Every node consists of one or more attributes describing the entity at that node. Dependent nodes can follow the succeeding levels. The node in the preceding level becomes the parent node of the new dependent nodes. A parent node can have one child node as a dependent or many children nodes. The major advantage of the hierarchical data model is the existence of proven database management systems that use the hierarchical data model as the basic structure. There is a reduction of data dependency but any child node is accessible only through its parent node, the many-to –many relationship can be implemented only in a clumsy way. This often results in a redundancy in stored data.The network data model interconnects the entities of an enterprise into a network. In the network data model a data base consists of a number of areas. An area contains records. In turn, a record may consist of fields. A set which is a grouping of records, may reside in an area or span a number of areas. A set type is based on the owner record type and the member record type. The many-to many relation-ship, which occurs quite frequently in real life can be implemented easily. The network data model is very complex, the application programmer must be familiar with the logical structure of the data base.4、Logical Design and Physical DesignLogical design of databases is mainly concerned with superimposing the constructs of the data base management system on the logical data model. There are three mainly models: hierarchical, relational, network we have mentioned above.The physical model is a framework of the database t o be stored on physical devices. The model must be constructed with every regard given to the performanceof the resulting database. One should carry out an analysis of the physical model with average frequencies of occurrences of the grou pings of the data elements, with expected space estimates, and with respect to time estimates for retrieving and maintaining the data.The database designer may find it necessary to have multiple entry points into a database, or to access a particular segment type with more than one key. To provide this type of access; it may be necessary to invert the segment on the keys. Thephysical designer must have expertise in knowledge of the DBMS functions and understanding of the characteristics of direct access d evices and knowledge of the applications.Many data bases have links between one record and another, called pointers. A pointer is a field in one record which indicates where a second record is located on the storage devices.Records that exist on storage devices is a given physical sequence. This sequencing may be employed for some purpose. The most common pupose is that records are needed in a given sequence by certain data-processing operations and so they are stored in that sequences.Different applications may need records in different sequences.The most common method of ordering records is to have them in sequence by a key—that key which is most commonly used for addressing them. An index is required to find any record without a lengthy search of the file.If the data records are laid out sequentially by key, the index for that key can be much smaller than they are nonsequential.Hashing has been used for addressing random-access s torages since they first came into existence in the mid-1950s. But nobody had the temerity to use the word hashing until 1968.Many systems analysis has avoided the use of hashing in the suspicion that it is complicated. In fact, it is simple to use and has two important advantages o ver indexing. First, it finds most records with only one seek and second, insertion and deletions can be handled without added complexity. Indexing, however, can be used with a file which is sequential by prime key and this is an overriding advantage, for some batch-pro-cessing applications.Many data-base systems use chains to interconnect records also. A chain refers to a group of records scatters within the files and interconnected by a sequence of pointers. The software that is used to retrive the chained records will make them appear to the application programmer as a contiguous logical file.The primary disadvantage o f chained records is that many read operations areneeded in order to follow lengthy chains. Sometimes this does not matter because the records have to be read anyway. In most search operations, however, the chains have to be followed through records which would not otherwise to read. In some file organizations the chains can be contained within blocked physical records so that excessive reads do not occur.Rings have been used in many file organizations. They are used to eliminate redundancy. When a ring or a chain is entered at a point some distance from its head, it may be desirable to obtain the information at the head quickly without stepping through all the intervening links.5、Data Description LanguagesIt is necessary for both the programmers and the data administrator to be able to describe their data precisely; they do so by means of data description languages. A data description language is the means of declaring to data-base management system what data structures will be used.A data description languages giving a logical data description should perform the folloeing functions:It should give a unique name to each data-item type, file type, data base and other data subdivision.It should identify the types of data subdivision such as data item segment , record and base file.It may define the type of encoding the program uses in the data items (binary , character ,bit string , etc.)It may define the length of the data items and the range of the values that a data item can assume .It may specify the sequence of records in a file or the sequence of groups of record in the data base .It may specify means of checking for errors in the data .It may specify privacy locks for preventing unauthorized reading or modificationof the data .These may operate at the data-item ,segment ,record, file or data-base level and if necessary may be extended to the contents(value) of individual data items .The authorization may , on the other hand, be separate d efined .It is more subject to change than the data structures, and changes in authorization proceduresshould not force changes in application programs.A logical data description should not specify addressing ,indexing ,or searching techniques or specify the placement of data on the storage units ,because these topics are in the domain of physical ,not logical organization .It may give an indication ofhow the data will be used or of searching requirement .So that the physical technique can be selected optimally but such indications should not be logically limiting.Most DBMS have their own languages for defining the schemas t hat are used . In most cases these data description languages are different to other programmer language, because other programmer do not have the capability to define to variety of relationship that may exit in the schemas.附录 B 外文译文1、软件工程软件是指令的序列，该指令序列由一种或多种程序语言编写，它能使计算机应用于某些事物的运用自动化。

西安邮电学院毕业设计（论文）外文文献翻译院系：计算机学院专业：软件工程班级：软件0601学生姓名：导师姓名：职称：副教授起止时间：2010年3月8日至2010年6月11日ClassesOne of the most compelling features about Java is code reuse. But to be revolutionary, you’ve got to be able to do a lot more than copy code and change it.That’s the approach used in procedural languages like C, and it hasn’t worked very well. Like everything in Java, the solution revolves around the class. You reuse code by creating new classes, but instead of creating them from scratch, you use existing classes that someone has already built and debugged.The trick is to use the classes without soiling the existing code.➢Initializing the base classSince there are now two classes involved—the base class and the derived class—instead of just one, it can be a bit confusing to try to imagine the resulting object produced by a derived class. From the outside, it looks like the new class has the same interface as the base class and maybe some additional methods and fields. But inheritance doesn’t just copy the interface of the base class. When you create an object of the derived class, it contains within it a subobject of the base class. This subobject is the same as if you had created an object of the base class by itself. It’s just that from the outside, the subobject of the base class is wrapped within the derived-class object.Of course, it’s essential that th e base-class subobject be initialized correctly, and there’s only one way to guarantee this: perform the initialization in the constructor by calling the base-class constructor, which has all the appropriate knowledge and privileges to perform the base-class initialization. Java automatically inserts calls to the base-class constructor in the derived-class constructor.➢Guaranteeing proper cleanupJava doesn’t have the C++ concept of a destructor, a method that is automatically called when an object is destroyed. The reason is probably that in Java, the practice is simply to forget about objects rather than to destroy them, allowing the garbage collector to reclaim the memory as necessary.Often this is fine, but there are times when your class might perform some activities during its lifetime that require cleanup. As mentioned in Chapter 4, you can’t know when the garbage collector will be called, or if it will be called. So if you want something cleaned up for a class, you must explicitly write a special method to do it, and make sure that the client programmer knows that they must call this method.Note that in your cleanup method, you must also pay attention to the calling order for the base-class and member-object cleanup methods in case one subobject depends on another. In general, you should follow the same form that is imposed by a C++ compiler on its destructors: first perform all of the cleanup work specific to your class, in the reverse order of creation. (In general, this requires that base-class elements still be viable.) Then call the base-class cleanup method, as demonstrated here➢Name hidingIf a Java base class has a method name that’s overloaded several times, redefining that method name in the derived class will not hide any of the base-class versions (unlike C++). Thus overloading works regardless of whether the method was defined at this level or in a base class，it’s far more common to override methods of the same name, using exactly the same signature and return type as in the base class. It can be confusing otherwise (which is why C++ disallows it—to prevent you from making what is probably a mistake).➢Choosing composition vs. inheritanceBoth composition and inheritance allow you to place subobjects inside your new class (composition explicitly does this—with inheritance it’s implicit). You might wonder about the difference between the two, and when to choose one over the other.Composition is generally used when you want the features of an existing class inside your new class, but not its interface. That is, you embed an object so that you can use it to implement functionality in your new class, but the user of your new class sees the interface you’ve defined for the new class rather than the interface from theembedded object. For this effect, you embed private objects of existing classes inside your new class.Sometimes it makes sense to allow the class user to directly access the composition of your new class; that is, to make the member objects public. The member objects use implementation hiding themselves, so this is a safe thing to do. When the user knows you’re assembling a bunch of parts, it makes the interface easier to understand.When you inherit, you take an existing class and make a special version of it. In general, this mea ns that you’re taking a general-purpose class and specializing it for a particular need➢The final keywordJava’s final keyword has slightly different meanings depending on the context, but in general it says “This cannot be changed.” You might want to prev ent changes for two reasons: design or efficiency. Because these two reasons are quite different, it’s possible to misuse the final keywordThe following sections discuss the three places where final can be used: for data, methods, and classes.➢Final dataMany programming languages have a way to tell the compiler that a piece of data is “constant.” A constant is useful for two reasons:It can be a compile-time constant that won’t ever change.It can be a value initialized at run time that you don’t want ch anged.In the case of a compile-time constant, the compiler is allowed to “fold” the constant value into any calculations in which it’s used; that is, the calculation can be performed at compile time, eliminating some run-time overhead. In Java, these sorts of constants must be primitives and are expressed with the final keyword. A value must be given at the time of definition of such a constant.A field that is both static and final has only one piece of storage that cannot be changed.When using final with object references rather than primitives, the meaning gets a bit confusing. With a primitive, final makes the value a constant, but with an object reference, final makes the reference a constant. Once the reference is initialized to an object, it can never be changed to point to another object. However, the object itself can be modified; Java does not provide a way to make any arbitrary object a constant. (You can, however, write your class so that objects have the effect of being constant.) This restriction includes arrays, which are also objects.➢Final methodsThere are two reasons for final methods. The first is to put a “lock” on the method to prevent any inheriting class from changing its meaning. This is done for design reasons when you want to mak e sure that a method’s behavior is retained during inheritance and cannot be overridden.The second reason for final methods is efficiency. If you make a method final, you are allowing the compiler to turn any calls to that method into inline calls. When the compiler sees a final method call, it can (at its discretion) skip the normal approach of inserting code to perform the method call mechanism (push arguments on the stack, hop over to the method code and execute it, hop back and clean off the stack arguments, and deal with the return value) and instead replace the method call with a copy of the actual code in the method body. This eliminates the overhead of the method call. Of course, if a method is big, then your code begins to bloat, and you probably won’t see any performance gains from inlining, since any improvements will be dwarfed by the amount of time spent inside the method. It is implied that the Java compiler is able to detect these situations and choose wisely whether to inline a final method. However, it’s best to let the compiler and JVM handle efficiency issues and make a method final only if you want to explicitly prevent overriding➢Final classesWhen you say that an entire class is final (by preceding its definition with the final keyword), you state that you don’t want to inherit from this class or allow anyone else to do so. In other words, for some reason the design of your class is suchthat there is never a need to make any changes, or for safety or security reasons you don’t want subc lassingNote that the fields of a final class can be final or not, as you choose. The same rules apply to final for fields regardless of whet However, because it prevents inheritance, all methods in a final class are implicitly final, since there’s no way to override them. You can add the final specifier to a method in a final class, but it doesn’t add any meaning.her the class is defined as final.➢SummaryBoth inheritance and composition allow you to create a new type from existing types. Typically, however, composition reuses existing types as part of the underlying implementation of the new type, and inheritance reuses the interface. Since the derived class has the base-class interface, it can be upcast to the base, which is critical for polymorphism, as you’ll see in the next chapter.Despite the strong emphasis on inheritance in object-oriented programming, when you start a design you should generally prefer composition during the first cut and use inheritance only when it is clearly necessary. Composition tends to be more flexible. In addition, by using the added artifice of inheritance with your member type, you can change the exact type, and thus the behavior, of those member objects at run time. Therefore, you can change the behavior of the composed object at run time.When designing a system, your goal is to find or create a set of classes in which each class has a specific use and is neither too big (encompassing so much functionality that it’s unwieldy to reuse) nor annoyingly small (you can’t use it by itself or without adding functionality).类“Java引人注目的一项特性是代码的重复使用或者再生。

软件系统开发中英文对照外文翻译文献(文档含英文原文和中文翻译)软件工程中的过程处理模型斯卡基沃尔特摘要软件系统从起初的开发，维护，再到一个版本升级到另一个版本，经历了一系列阶段。

这篇文章归纳和整理了一些描述如何开发软件系统的方法。

从传统的软件生命周期的背景和定义出发，即大多数教科书所讨论的，并且目前的软件开发实践所遵循的软件生命周期，接着讨论作为目前软件工程技术基石的更全面的软件开发模型。

关键词：软件生命周期；模型；原型1 前言软件业的发展最早可追溯到开发大型软件项目的显式模型，那是在二十世纪五十年代和六十年代间。

总体而言，这些早期的软件生命周期模型的唯一目的就是提供一个合理的概念计划来管理软件系统的开发。

因此，这种计划可以作为一个基础规划，组织，人员配备，协调，预算编制，并指导软件开发活动。

自20世纪60年代，出现了许多经典的软件生命周期的描述（例如，霍西尔1961年，劳斯莱斯1970年，1976年博伊姆，迪斯塔索1980年，1984年斯卡基，萨默维尔1999年）。

罗伊斯（1970）使用现在生活中熟悉的“瀑布”图表，提出了周期的概念，这个图表概括了开发大型软件系统是多么的困难，因为它涉及复杂的工程任务，而这些任务在完成之前可能需要不断地返工。

这些图表也通常在介绍性发言中被采用，主要针对开发大型软件系统的人们（例如，定制软件的客户），他们可能不熟悉各种各样的技术问题但还是要必须解决这些问题。

这些经典的软件生命周期模型通常包括以下活动一些内容：系统启动/规划：系统从何而来？在大多数情况下，不论是现有的信息处理机制以前是自动的，手工的，还是非正式的，新系统都会取代或补充它们。

● 需求分析和说明书：阐述一个新的软件系统将要开发的问题：其业务能力，其所达到的性能特点，支持系统运行和维护所需的条件。

● 功能或原型说明：潜在确定计算的对象，它们的属性和关系，改变这些对象的操作，约束系统行为的限制等。

●划分与选择：给出需求和功能说明书，将系统分为可管理的模块，它们是逻辑子系统的标志，然后确定是否有对应于这些模块的新的，现有的，或可重复使用的软件系统可以复用。

安卓应用开发中英文对照外文翻译文献(文档含英文原文和中文翻译)中英文翻译安卓应用开发基础在Java编程语言编写的Android应用程序的Android的SDK工具编译代码以及与任何数据和到一个Android的包，一个归档文件档案资源的.apk后缀，所有的在一个单一的代码.apk文件被认为是一个应用程序，是Android的文件，供电设备来安装应用程序。

一旦安装在设备上，每个Android应用程序的生命在它自己的安全沙箱：而Android操作系统是一个多用户Linux系统中，每个应用程序是一个不同的用户。

默认情况下，每个应用程序的系统分配一个唯一的Linux用户ID （该ID仅用于由系统是未知的应用程序），系统设置所有的应用程序中的文件权限，以便只有用户ID分配给该应用程序可以访问它们。

每个进程都有它自己的虚拟机（VM），因此应用程序的代码在从其他应用程序隔离运行。

默认情况下，每个应用程序运行在它自己的Linux进程。

Android 的启动过程时，应用程序的任何组件需要被执行，然后关闭该进程时，它不再需要或恢复时，系统必须为其他应用程序的内存。

这样一来，Android系统实现了最小特权原则，也就是说，每个应用程序，默认情况下，只能访问的组件，它需要做的工作，没有更多，这将创建一个非常安全的环境，使应用程序无法访问的，这就是它没有给予许可制度的部分。

但是，有一个应用程序的方法与其他应用程序和应用程序访问系统服务的数据：这有可能为两个应用程序安排共享相同的Linux用户ID，在这种情况下，它们能够相互访问的文件。

为了节约使用相同的用户ID系统资源，应用程序还可以安排运行在相同的Linux进程和共享同一个VM （应用也必须使用相同的证书签名）。

应用程序可以请求访问权限，如用户的联系人，短信，可安装存储（SD卡），摄像头，蓝牙等设备的数据，所有应用程序的权限必须由用户在安装时授予。

这涵盖了基本就如何Android应用程序在系统中存在这个文件的其余部分向您介绍：1、框架的核心组件定义应用程序。

软件工程外文翻译文献(文档含中英文对照即英文原文和中文翻译)Software engineeringSoftware engineering is the study of the use of engineering methods to build and maintain effective, practical and high-quality software disciplines. It involves the programming language, database, software development tools, system platform, standards, design patterns and so on.In modern society, the software used in many ways. Typical software such as email, embedded systems, human-machine interface, office packages, operating systems, compilers, databases, games. Meanwhile, almost all the various sectors of computer software applications, such as industry, agriculture, banking, aviation and government departments. These applications facilitate the economic and social development,improve people's working efficiency, while improving the quality of life. Software engineers is to create software applications of people collectively, according to which software engineers can be divided into different areas of system analysts, software designers, system architects, programmers, testers and so on. It is also often used to refer to a variety of software engineers, programmers.OriginIn view of difficulties encountered in software development, North Atlantic Treaty Organization (NATO) in 1968 organized the first Conference on Software Engineering, and will be presented at the "software engineering" to define the knowledge required for software development, and suggested that "software development the activities of similar projects should be. " Software Engineering has formally proposed since 1968, this time to accumulate a large number of research results, widely lot of technical practice, academia and industry through the joint efforts of software engineering is gradually developing into a professional discipline.Definitioncreation and use of sound engineering principles in order to obtain reliable and economically efficient software.application of systematic, follow the principle can be measured approach to development, operation and maintenance of software; that is to beapplied to software engineering.The development, management and updating software products related to theories, methods and tools.A knowledge or discipline (discipline), aims to produce good quality, punctual delivery, within budget and meet users need software.the practical application of scientific knowledge in the design, build computer programs, and the accompanying documents produced, and the subsequent operation and maintenance.Use systematic production and maintenance of software products related to technology and management expertise to enable software development and changes in the limited time and under cost.Construction team of engineers developed the knowledge of large software systems disciplines.the software analysis, design, implementation and maintenance of a systematic method.the systematic application of tools and techniques in the development of computer-based applications.Software Engineering and Computer ScienceSoftware development in the end is a science or an engineering, this is a question to be debated for a long time. In fact, both the two characteristics of software development. But this does not mean that they can be confused with each other. Many people think that softwareengineering, computer science and information science-based as in the traditional sense of the physical and chemical engineering as. In the U.S., about 40% of software engineers with a degree in computer science. Elsewhere in the world, this ratio is also similar. They will not necessarily use every day knowledge of computer science, but every day they use the software engineering knowledge.For example, Peter McBreen that software "engineering" means higher degree of rigor and proven processes, not suitable for all types of software development stage. Peter McBreen in the book "Software Craftsmanship: The New Imperative" put forward the so-called "craftsmanship" of the argument, consider that a key factor in the success of software development, is to develop the skills, not "manufacturing" software process.Software engineering and computer programmingSoftware engineering exists in a variety of applications exist in all aspects of software development. The program design typically include program design and coding of the iterative process, it is a stage of software development.Software engineering, software project seeks to provide guidance in all aspects, from feasibility analysis software until the software after completion of maintenance work. Software engineering that software development and marketing activities are closely related. Such assoftware sales, user training, hardware and software associated with installation. Software engineering methodology that should not be an independent programmer from the team and to develop, and the program of preparation can not be divorced from the software requirements, design, and customer interests.Software engineering design of industrial development is the embodiment of a computer program.Software crisisSoftware engineering, rooted in the 20th century to the rise of 60,70 and 80 years of software crisis. At that time, many of the software have been a tragic final outcome. Many of the software development time significantly beyond the planned schedule. Some projects led to the loss of property, and even some of the software led to casualties. While software developers have found it increasingly difficult for software development.OS 360 operating system is considered to be a typical case. Until now, it is still used in the IBM360 series host. This experience for decades, even extremely complex software projects do not have a set of programs included in the original design of work systems. OS 360 is the first large software project, which uses about 1,000 programmers. Fred Brooks in his subsequent masterpiece, "The Mythical Man Month" (The Mythical Man-Month) in the once admitted that in his management of theproject, he made a million dollar mistake.Property losses: software error may result in significant property damage. European Ariane rocket explosion is one of the most painful lesson.Casualties: As computer software is widely used, including hospitals and other industries closely related to life. Therefore, the software error might also result in personal injury or death.Was used extensively in software engineering is the Therac-25 case of accidents. In 1985 between June and January 1987, six known medical errors from the Therac-25 to exceed the dose leads to death or severe radiation burns.In industry, some embedded systems do not lead to the normal operation of the machine, which will push some people into the woods. MethodologyThere are many ways software engineering aspects of meaning. Including project management, analysis, design, program preparation, testing and quality control.Software design methods can be distinguished as the heavyweight and lightweight methods. Heavyweight methods produce large amounts of official documentation.Heavyweight development methodologies, including the famous ISO 9000, CMM, and the Unified Process (RUP).Lightweight development process is not an official document of the large number of requirements. Lightweight methods, including well-known Extreme Programming (XP) and agile process (Agile Processes).According to the "new methodology" in this article, heavyweight method presented is a "defensive" posture. In the application of the "heavyweight methods" software organizations, due to a software project manager with little or no involvement in program design, can not grasp the item from the details of the progress of the project which will have a "fear", constantly had to ask the programmer to write a lot of "software development documentation." The lightweight methods are presented "aggressive" attitude, which is from the XP method is particularly emphasized four criteria - "communication, simplicity, feedback and courage" to be reflected on. There are some people that the "heavyweight method" is suitable for large software team (dozens or more) use, and "lightweight methods" for small software team (a few people, a dozen people) to use. Of course, on the heavyweight and lightweight method of approach has many advantages and disadvantages of debate, and various methods are constantly evolving.Some methodologists think that people should be strictly followed in the development and implementation of these methods. But some people do not have the conditions to implement these methods. In fact, themethod by which software development depends on many factors, but subject to environmental constraints.Software development processSoftware development process, with the subsequent development of technology evolution and improvement. From the early waterfall (Waterfall) development model to the subsequent emergence of the spiral iterative (Spiral) development, which recently began the rise of agile development methodologies (Agile), they showed a different era in the development process for software industry different awareness and understanding of different types of projects for the method.Note distinction between software development process and software process improvement important difference between. Such as ISO 15504, ISO 9000, CMM, CMMI such terms are elaborated in the framework of software process improvement, they provide a series of standards and policies to guide software organizations how to improve the quality of the software development process, the ability of software organizations, and not give a specific definition of the development process.Development of software engineering"Agile Development" (Agile Development) is considered an important software engineering development. It stressed that software development should be able to possible future changes and uncertaintiesof a comprehensive response.Agile development is considered a "lightweight" approach. In the lightweight approach should be the most prestigious "Extreme Programming" (Extreme Programming, referred to as XP).Correspond with the lightweight approach is the "heavyweight method" exists. Heavyweight approach emphasizes the development process as the center, rather than people-centered. Examples of methods such as heavyweight CMM / PSP / TSP.Aspect-oriented programming (Aspect Oriented Programming, referred to as the AOP) is considered to software engineering in recent years, another important development. This aspect refers to the completion of a function of a collection of objects and functions. In this regard the contents related to generic programming (Generic Programming) and templates.软件工程软件工程是一门研究用工程化方法构建和维护有效的、实用的和高质量的软件的学科。

软件工程专业毕业设计外文文献翻译1000字本文将就软件工程专业毕业设计的外文文献进行翻译，能够为相关考生提供一定的参考。

外文文献1: Software Engineering Practices in Industry: A Case StudyAbstractThis paper reports a case study of software engineering practices in industry. The study was conducted with a large US software development company that produces software for aerospace and medical applications. The study investigated the company’s software development process, practices, and techniques that lead to the production of quality software. The software engineering practices were identified through a survey questionnaire and a series of interviews with the company’s software development managers, software engineers, and testers. The research found that the company has a well-defined software development process, which is based on the Capability Maturity Model Integration (CMMI). The company follows a set of software engineering practices that ensure quality, reliability, and maintainability of the software products. The findings of this study provide a valuable insight into the software engineering practices used in industry and can be used to guide software engineering education and practice in academia.IntroductionSoftware engineering is the discipline of designing, developing, testing, and maintaining software products. There are a number of software engineering practices that are used in industry to ensure that software products are of high quality, reliable, and maintainable. These practices include software development processes, software configuration management, software testing, requirements engineering, and project management. Software engineeringpractices have evolved over the years as a result of the growth of the software industry and the increasing demands for high-quality software products. The software industry has developed a number of software development models, such as the Capability Maturity Model Integration (CMMI), which provides a framework for software development organizations to improve their software development processes and practices.This paper reports a case study of software engineering practices in industry. The study was conducted with a large US software development company that produces software for aerospace and medical applications. The objective of the study was to identify the software engineering practices used by the company and to investigate how these practices contribute to the production of quality software.Research MethodologyThe case study was conducted with a large US software development company that produces software for aerospace and medical applications. The study was conducted over a period of six months, during which a survey questionnaire was administered to the company’s software development managers, software engineers, and testers. In addition, a series of interviews were conducted with the company’s software development managers, software engineers, and testers to gain a deeper understanding of the software engineering practices used by the company. The survey questionnaire and the interview questions were designed to investigate the software engineering practices used by the company in relation to software development processes, software configuration management, software testing, requirements engineering, and project management.FindingsThe research found that the company has a well-defined software development process, which is based on the Capability Maturity Model Integration (CMMI). The company’s software development process consists of five levels of maturity, starting with an ad hoc process (Level 1) and progressing to a fully defined and optimized process (Level 5). The company has achieved Level 3 maturity in its software development process. The company follows a set of software engineering practices that ensure quality, reliability, and maintainability of the software products. The software engineering practices used by the company include:Software Configuration Management (SCM): The company uses SCM tools to manage software code, documentation, and other artifacts. The company follows a branching and merging strategy to manage changes to the software code.Software Testing: The company has adopted a formal testing approach that includes unit testing, integration testing, system testing, and acceptance testing. The testing process is automated where possible, and the company uses a range of testing tools.Requirements Engineering: The company has a well-defined requirements engineering process, which includes requirements capture, analysis, specification, and validation. The company uses a range of tools, including use case modeling, to capture and analyze requirements.Project Management: The company has a well-defined project management process that includes project planning, scheduling, monitoring, and control. The company uses a range of tools to support project management, including project management software, which is used to track project progress.ConclusionThis paper has reported a case study of software engineering practices in industry. The study was conducted with a large US software development company that produces software for aerospace and medical applications. The study investigated the company’s software development process,practices, and techniques that lead to the production of quality software. The research found that the company has a well-defined software development process, which is based on the Capability Maturity Model Integration (CMMI). The company uses a set of software engineering practices that ensure quality, reliability, and maintainability of the software products. The findings of this study provide a valuable insight into the software engineering practices used in industry and can be used to guide software engineering education and practice in academia.外文文献2: Agile Software Development: Principles, Patterns, and PracticesAbstractAgile software development is a set of values, principles, and practices for developing software. The Agile Manifesto represents the values and principles of the agile approach. The manifesto emphasizes the importance of individuals and interactions, working software, customer collaboration, and responding to change. Agile software development practices include iterative development, test-driven development, continuous integration, and frequent releases. This paper presents an overview of agile software development, including its principles, patterns, and practices. The paper also discusses the benefits and challenges of agile software development.IntroductionAgile software development is a set of values, principles, and practices for developing software. Agile software development is based on the Agile Manifesto, which represents the values and principles of the agile approach. The manifesto emphasizes the importance of individuals and interactions, working software, customer collaboration, and responding to change. Agile software development practices include iterative development, test-driven development, continuous integration, and frequent releases.Agile Software Development PrinciplesAgile software development is based on a set of principles. These principles are:Customer satisfaction through early and continuous delivery of useful software.Welcome changing requirements, even late in development. Agile processes harness change for the customer's competitive advantage.Deliver working software frequently, with a preference for the shorter timescale.Collaboration between the business stakeholders and developers throughout the project.Build projects around motivated individuals. Give them the environment and support they need, and trust them to get the job done.The most efficient and effective method of conveying information to and within a development team is face-to-face conversation.Working software is the primary measure of progress.Agile processes promote sustainable development. The sponsors, developers, and users should be able to maintain a constant pace indefinitely.Continuous attention to technical excellence and good design enhances agility.Simplicity – the art of maximizing the amount of work not done – is essential.The best architectures, requirements, and designs emerge from self-organizing teams.Agile Software Development PatternsAgile software development patterns are reusable solutions to common software development problems. The following are some typical agile software development patterns:The Single Responsibility Principle (SRP)The Open/Closed Principle (OCP)The Liskov Substitution Principle (LSP)The Dependency Inversion Principle (DIP)The Interface Segregation Principle (ISP)The Model-View-Controller (MVC) PatternThe Observer PatternThe Strategy PatternThe Factory Method PatternAgile Software Development PracticesAgile software development practices are a set ofactivities and techniques used in agile software development. The following are some typical agile software development practices:Iterative DevelopmentTest-Driven Development (TDD)Continuous IntegrationRefactoringPair ProgrammingAgile Software Development Benefits and ChallengesAgile software development has many benefits, including:Increased customer satisfactionIncreased qualityIncreased productivityIncreased flexibilityIncreased visibilityReduced riskAgile software development also has some challenges, including:Requires discipline and trainingRequires an experienced teamRequires good communicationRequires a supportive management cultureConclusionAgile software development is a set of values, principles, and practices for developing software. Agile software development is based on the Agile Manifesto, which represents the values and principles of the agile approach. Agile software development practices include iterative development, test-driven development, continuous integration, and frequent releases. Agile software development has many benefits, including increased customer satisfaction, increased quality, increased productivity, increased flexibility, increased visibility, and reduced risk. Agile software development also has some challenges, including the requirement for discipline and training, the requirement for an experienced team, the requirement for good communication, and the requirement for a supportive management culture.。

JAVA学习过程论文中英文资料对照外文翻译文献Java Learning Path processEach person's study method is different, a person's method suits another person not necessarily, I only can discuss own study method. Because I study Java am study independently completely, has not asked others, therefore the study process basically is completely oneself tries to find out. I did not know whether this method is the quite good method, only could give everybody to provide refers.Studies Java first step installs good JDK, writes Hello World? Actually the JDK study is not so simple, has two questions about JDK is very easy to puzzle the Java programmer continuously the place: Is the CLASSPATH question, actually said from the principle, is how must make clear JRE ClassLoader increase Class; Another question is package and the import question, how seeks the kind of way question. These two questions tried to find out clear, eliminated has studied Java and uses JDK the biggest barrier. The recommendation looked Wang Sen "the Java Depth Experiences dangers", has carried on the thorough discussion to these two questionsSecond step is studies Java the grammar. The Java grammar is kind of C++, the basically mainstream programming language is not kind of C, is kind of C++, does not have what new thing, therefore the grammar study, probably was the quite a while time is enough. Only needs to pay attention is has the key words usage which several is not easy to make clear, public, protected, private, static, when uses, why has to use, how uses, this possible need some people to direct, I initially was own ponder over completely, has spent the very long time. But afterwards I saw above this book spoke these concepts to "Thinking in Java".Third step is studies Java the object-oriented programming language characteristic place. For instance inherits, structure, abstract class, the connection, the method are many condition, heavy load, cover, Java exception handling mechanism. Said regarding a not object-oriented language background person that, I thought this process needs to spend the very long very long time, because studies in front of Java does not have C++ the experience, only then the C experience, I was have probably spent for a month, all made clear only then thoroughly these concepts, book example above repeatedly estimating, the revision, the attempt, repeatedly looked at that several chapter of contents, looked, looked has not gotten down 5, comprehended only then thoroughly. But I thought if has the C++ experience, should 12 days time be enough. Then in this process, may have a look "Thinking in Java" this book, opposite is extremely thorough to the object explanation. What a pity is I studies, has not seen to this book, therefore own have spent the massive time, and estimates through own attempt learns.Fourth step starts a familiar Java kind of storehouse. The Java foundation class storehouse actually is JDK installs under the table of contentsjre\Lib\Rt.Jar this package. The study foundation class storehouse studies rt.Jar. Inside the foundation class storehouse kind are extremely extremely many. It is said some more than 3,000, I have not counted. But said the most core truly regarding us only then 4, respectively isng.*;Java.Io.*;Java.Util.*;Java.Sql.*;These four packages study, each package study all may write thick teaching material, but O'reilly also truly is does this. I thought if time quite tight, is impossible through to read four books to study. I thought the quite good study method is such:First must read through entire package the frame, understood entire package class, interface, the exception constitution, should better be can find the introduction entire package frame the article. These introduced specially package of books the first several chapters should be these overall frame content introductions. Is not must be familiar with each kind of usage to the package of overall frame assurance, which attributes remembers it have, the method. Wants to record also cannot remember. But is must know which aspects the package does have a kind of constitution, these kind of uses are any, most core several classifications maybe complete any function. I in the time which trains to the human generally is a class speaks a package, therefore not impossible detailed introduction each kind of usage, but I repeatedly stress, how do I speak these packages to you am must tell you a kind of method am transfer, also does not request you to remember the kind of method transfer, but wants you tounderstand, which kinds Java has provided to us, each kind is uses in any situation, when I meet the question the time, I knew which kind, or which several kind of combinations can solve my problem, That'all! When we write the procedure specifically time, so long as you knew which kind should complete your work with to be enough. Codes, the concrete method transfer, writes the code, Documentation, all things all inside Documentation, will not request you certainly to remember, are actual you also not to be able to remember more than 3,000 kinds altogether the nearly 100,000 methods transfers. Therefore changes to each package overall frame assurance extremely importantly.Fifth step, through above study, if study the quite solid speech, built the Java foundation, is left over the work which had to do is sweeps clean inside Documentation besides above 4 packages other some comparisons to have the use the kind. Believed progressed to this step, Java studies independently the ability already to raise, might to study Documentation directly horizontal. Besides must make the GUI programming, inside JDK other can have the use the package is these:Java.Text.*;.*;Javax.Naming.*;These packages of inside real correct uses quite many kinds very are actually few, only then several, therefore does not need to spend the very much time.Sixth step, Java Web programmingThe Web programming core is the HTTP agreement, the HTTP agreement and Java irrelevant, if not familiar HTTP agreement, although also may learnServlet/JSP programming, but cannot achieve extrapolates, by knowing one method you will know all boundary. Therefore the HTTP agreement study is necessary. If has been familiar with HTTP agreement, also had the Java programming good foundation, studies Servlet/JSP is simply easy as pie, I study Servlet/JSP has used not to week-long time, then started with JSP to make the project. In Servlet/In the JSP study, heavy still was Servlet Documentation. Servlet the API most commonly used kind are very few, the flowered quite few time might grasp. These kinds all looked at, writes several examples to try. Servlet/The JSP programming essence is transferring these kinds to come repeatedly through the HTTP agreement converses between Web Server and Brower. Moreover to JSP, but also needs to be familiar with several commonly used JSP the mark, the concrete mode of writing cannot remember the speech, looks up temporarily and that's the end of.In addition Java the Web programming study must place Web Application with emphasis in the design pattern, how carries on the service logic the analysis, and carries on the reasonable design, according to the MVC design pattern request, completes the different logical level separately using Servlet and JSP, how grasps carries on the flow between Servlet and JSP the control and data sharing, as well as how Web should Application dispose and the deployment.Seventh step, J2EE programmingThe above study process if is quite smooth, carries on to this step, the difficulty enhances suddenly. Because the above knowledge content all only involves an aspect, but likes EJB, JMS, core the and so on JTA J2EE standard often is several kind of Java technology synthesis utilization crystallization, therefore grasps the difficulty quite to be big.First certainly must study good JNDI, JNDI is App the Server localization server resources (the EJB module, Datasouce, JMS) searches the method, if to JNDI not familiar, EJB, JMS these things cannot study nearly. JNDI actually is javax.Naming.* This package, utilizes is very simple. The difficulty lies in the server resources document the disposition. Regarding the server resources document disposition, needed to have a look the special documents to be standard, for instance web.Xml mode of writing, ejb-jar.Xml mode of writing and so on. In view of each kind of different App Server, but also has own service resources disposition document, also is needs to be familiar with.Then may study JTA, mainly is must understand JTA regarding business control method, as well as should use JTA in any situation. Here may simple cite an example, we knew the ordinary circumstances may carry on business regarding a database connection (conn.SetAutoCommit (false)....,mit ()), does is an atomic operation, but the supposition my service demand is needs to hold artificially to two different databases is an atomic operation, you can do to? At this time only could use JTA. The supposition operating process inserts a record first toward the A database, then deletes the B database another record, we wrote the code are cannot control entire hold artificially are an atomic operation. With the JTA speech, completes the control by App Server.In studies in front of EJB must study the object sequence and RMI, RMI is the EJB foundation. Then studies JMS and EJB, said regarding EJB, most is essential is must understand how EJB is realizes through RMI to the far-end object transfer, as well as must use in any situation to EJB.In studies EJB, after JMS these things, you possibly can realize must extremely anxiously study two domains the knowledge, is UML, another isDesign Pattern. The Java enterprise software design takes the frame extremely (Framework) the design, a good software frame is the software develops the successful essential condition. In this time, should start the study key point to place the design pattern and in the frame study, experiences through the study and the actual programming grasps EJB the design pattern and the J2EE core pattern.Inside J2EE standard, except EJB, JMS, JTA, Servlet/JSP, outside JDBC also has the very many very many enterprises technology, here 11 did not carry on introducedMoreover also has newest domain Web Services. Web Services also completely does not have any new thing, it likes is one kind of adhesive, may unify the different service provides a unified transfer connection, said as the user, I so long as obtain the service provider for mine WSDL (to service description), has sufficed, I did not know completely the server tenderer provides actually the service is the EJB module,The Net module, any CORBA module, other any realizations, I do not need to know. Web the Services greatest place lies in through the unified service provides the way and the transfer way, has realized the entire Internet service sharing, is an extremely excited area of technology. Web Services resembles at present not to have any very good books, but may through look up the material above the network the way to study.JA V A学习过程每个人的学习方法是不同的，一个人的方法不见得适合另一个人，我只能是谈自己的学习方法。

英文原文 Overview is a unified Web development model that includes the services necessary for you to build enterprise-class Web applications with a minimum of coding. is part of the .NET Framework, and when coding applications you have access to classes in the .NET Framework. Y ou can code your applications in any language compatible with the common language runtime (CLR), including Microsoft Visual Basic, C#, JScript .NET, and J#. These languages enable you to develop applications that benefit from the common language runtime, type safety, inheritance, and so on. includes:A page and controls frameworkThe compilerSecurity infrastructureState-management facilitiesApplication configurationHealth monitoring and performance featuresDebugging supportAn XML Web services frameworkExtensible hosting environment and application life cycle managementAn extensible designer environmentThe page and controls framework is a programming framework that runs on a Web server to dynamically produce and render Web pages. Web pages can be requested from any browser or client device, and renders markup (such as HTML) to the requesting browser. Web pages are completely object-oriented. Within Web pages you can work with HTML elements using properties, methods, and events. The page framework removes the implementation details of the separation of client and server inherent in Web-based applications by presenting a unified model forresponding to client events in code that runs at the server. The framework also automatically maintains the state of a page and the controls on that page during the page processing life cycle.The page and controls framework also enables you to encapsulate common UI functionality in easy-to-use, reusable controls. Controls are written once, can be used in many pages, and are integrated into the Web page that they are placed in during rendering.The page and controls framework also provides features to control the overall look and feel of your Web site via themes and skins. Y ou can define themes and skins and then apply them at a page level or at a control level.All code is compiled, which enables strong typing, performance optimizations, and early binding, among other benefits. Once the code has been compiled, the common language runtime further compiles code to native code, providing improved performance. includes a compiler that will compile all your application components including pages and controls into an assembly that the hosting environment can then use to service user requests.In addition to the security features of .NET, provides an advanced security infrastructure for authenticating and authorizing user access as well as performing other security-related tasks. Y ou can authenticate users using Windows authentication supplied by IIS, or you can manage authentication using your own user database using forms authentication and membership. Additionally, you can manage the authorization to the capabilities and information of your Web application using Windows groups or your own custom role database using roles. Y ou can easily remove, add to, or replace these schemes depending upon the needs of your application. always runs with a particular Windows identity so you can secure your application using Windows capabilities such as NTFS Access Control Lists (ACLs), database permissions, and so on. For more information on the identity of , provides intrinsic state management functionality that enables you tostore information between page requests, such as customer information or the contents of a shopping cart. Y ou can save and manage application-specific, session-specific, page-specific, user-specific, and developer-defined information. This information can be independent of any controls on the page. offers distributed state facilities, which enable you to manage state information across multiple instances of the same application on one computer or on several computers. applications use a configuration system that enables you to define configuration settings for your Web server, for a Web site, or for individual applications. Y ou can make configuration settings at the time your applications are deployed and can add or revise configuration settings at any time with minimal impact on operational Web applications and servers. configuration settings are stored in XML-based files. Because these XML files are ASCII text files, it is simple to make configuration changes to your Web applications. Y ou can extend the configuration scheme to suit your requirements. includes features that enable you to monitor health and performance of your application. health monitoring enables reporting of key events that provide information about the health of an application and about error conditions. These events show a combination of diagnostics and monitoring characteristics and offer a high degree of flexibility in terms of what is logged and how it is logged. supports two groups of performance counters accessible to your applications:The system performance counter groupThe application performance counter group takes advantage of the run-time debugging infrastructure to provide cross-language and cross-computer debugging support. Y ou can debug both managed and unmanaged objects, as well as all languages supported by the common language runtime and script languages.In addition, the page framework provides a trace mode that enablesyou to insert instrumentation messages into your Web pages. supports XML Web services. An XML Web service is a component containing business functionality that enables applications to exchange information across firewalls using standards like HTTP and XML messaging. XML Web services are not tied to a particular component technology or object-calling convention. As a result, programs written in any language, using any component model, and running on any operating system can access XML Web services. includes an extensible hosting environment that controls the life cycle of an application from when a user first accesses a resource (such as a page) in the application to the point at which the application is shut down. While relies on a Web server (IIS) as an application host, provides much of the hosting functionality itself. The architecture of enables you to respond to application events and create custom HTTP handlers and HTTP modules.Introduction to the C# Language and the .NET Framework C# is an elegant and type-safe object-oriented language that enables developers to build a wide range of secure and robust applications that run on the .NET Framework. Y ou can use C# to create traditional Windows client applications, XML Web services, distributed components, client-server applications, database applications, and much, much more. Microsoft Visual C# 2005 provides an advanced code editor, convenient user interface designers, integrated debugger, and many other tools to facilitate rapid application development based on version 2.0 of the C# language and the .NET Framework.The Visual C# documentation assumes that you have an understanding of basic programming concepts. If you are a complete beginner, you might want to explore Visual C# Express Edition, which is available on the Web. Y ou can also take advantage of any of several excellent books and Web resources on C# to learn practical programming skills.C# syntax is highly expressive, yet with less than 90 keywords, it is also simple and easy to learn. The curly-brace syntax of C# will be instantly recognizable to anyone familiar with C, C++ or Java. Developers who know any of these languages are typically able to begin working productively in C# within a very short time. C#syntax simplifies many of the complexities of C++ while providing powerful features such as nullable value types, enumerations, delegates, anonymous methods and direct memory access, which are not found in Java. C# also supports generic methods and types, which provide increased type safety and performance, and iterators, which enable implementers of collection classes to define custom iteration behaviors that are simple to use by client code.As an object-oriented language, C# supports the concepts of encapsulation, inheritance and polymorphism. All variables and methods, including the Main method, the application's entry point, are encapsulated within class definitions. A class may inherit directly from one parent class, but it may implement any number of interfaces. Methods that override virtual methods in a parent class require the override keyword as a way to avoid accidental redefinition. In C#, a struct is like a lightweight class; it is a stack-allocated type that can implement interfaces but does not support inheritance.In addition to these basic object-oriented principles, C# facilitates the development of software components through several innovative language constructs, including:C# programs run on the .NET Framework, an integral component of Windows that includes a virtual execution system called the common language runtime (CLR) and a unified set of class libraries. The CLR is Microsoft's commercial implementation of the common language infrastructure (CLI), an international standard that is the basis for creating execution and development environments in which languages and libraries work together seamlessly.Source code written in C# is compiled into an intermediate language (IL) that conforms to the CLI specification. The IL code, along with resources such as bitmaps and strings, is stored on disk in an executable file called an assembly, typically with an extension of .exe or .dll. An assembly contains a manifest that provides information on the assembly's types, version, culture, and security requirements.中文翻译 概述 是一个统一的Web 开发模型，它包括您使用尽可能少的代码生成企业级Web 应用程序所必需的各种服务。

外文文献原文THE TECHNIQUE DEVELOPMENT HISTORY OF JSPThe Java Server Pages( JSP) is a kind of according to web of the script plait distance technique, similar carries the script language of Java in the server of the Netscape company of server- side JavaScript( SSJS) and the Active Server Pages(ASP) of the Microsoft. JSP compares the SSJS and ASP to have better can expand sex, and it is no more exclusive than any factory or some one particular server of Web. Though the norm of JSP is to be draw up by the Sun company of, any factory can carry out the JSP on own system.The After Sun release the JSP( the Java Server Pages) formally, the this kind of new Web application development technique very quickly caused the people's concern. JSP provided a special development environment for the Web application that establishes the high dynamic state. According to the Sun parlance, the JSP can adapt to include the Apache WebServer, IIS4.0 on the market at inside of 85% server product.This chapter will introduce the related knowledge of JSP and Databases, and JavaBean related contents, is all certainly rougher introduction among them basic contents, say perhaps to is a Guide only, if the reader needs the more detailed information, pleasing the book of consult the homologous JSP.1.1 GENERALIZEThe JSP(Java Server Pages) is from the company of Sun Microsystems initiate, the many companies the participate to the build up the together of the a kind the of dynamic the state web the page technique standard, the it have the it in the construction the of the dynamic state the web page the strong but the do not the especially of the function. JSP and the technique of ASP of the Microsoft is very alike. Both all provide the ability that mixes with a certain procedure code and is explain by the language engine to carry out the procedure code in the code of HTML. Underneath we are simple of carry on the introduction to it.JSP pages are translated into servlets. So, fundamentally, any task JSP pages can perform could also be accomplished by servlets. However, this underlying equivalence does not mean that servlets and JSP pages are equally appropriate in all scenarios. The issue is not the power of the technology, it is the convenience, productivity, and maintainability of one or the other. After all, anything you can do on a particular computer platform in the Java programming language you could also do in assembly language. But it still matters which you choose.JSP provides the following benefits over servlets alone:• It is easier to write and maintain the HTML. Your static code is ordinary HTML: no extra backslashes, no double quotes, and no lurking Java syntax.• You can use standard Web-site development tools. Even HTML tools that know nothing about JSP can be used because they simply ignore the JSP tags.• You can divide up your development team. The Java programmers can work on the dynamic code. The Web developers can concentrate on the presentation layer. On large projects, this division is very important. Depending on the size of your team and the complexity of your project, you can enforce a weaker or stronger separation between the static HTML and the dynamic content.Now, this discussion is not to say that you should stop using servlets and use only JSP instead. By no means. Almost all projects will use both. For some requests in your project, you will use servlets. For others, you will use JSP. For still others, you will combine them with the MVC architecture . You want the appropriate tool for the job, and servlets, by themselves, do not complete your toolkit.1.2 SOURCE OF JSPThe technique of JSP of the company of Sun, making the page of Web develop the personnel can use the HTML perhaps marking of XML to design to turn the end page with format. Use the perhaps small script future life of marking of JSP becomes the dynamic state on the page contents.( the contents changes according to the claim of)The Java Servlet is a technical foundation of JSP, and the large Web applies the development of the procedure to need the Java Servlet to match with with the JSP and then can complete, this name of Servlet comes from the Applet, the local translation method of now is a lot of, this book in order not to misconstruction, decide the direct adoption Servlet but don't do any translation, if reader would like to, can call it as" small service procedure". The Servlet is similar to traditional CGI, ISAPI, NSAPI etc. Web procedure development the function of the tool in fact, at use the Java Servlet hereafter, the customer need not use again the lowly method of CGI of efficiency, also need not use only the ability come to born page of Web of dynamic state in the method of API that a certain fixed Web server terrace circulate. Many servers of Web all support the Servlet, even not support the Servlet server of Web directly and can also pass the additional applied server and the mold pieces to support the Servlet. Receive benefit in the characteristic of the Java cross-platform, the Servlet is also a terrace irrelevant, actually, as long as match the norm of Java Servlet, the Servlet is complete to have nothing to do with terrace and is to have nothing to do with server of Web. Because the Java Servlet is internal to provide the service by the line distance, need not start a progress to the each claimses, and make use of the multi-threadingmechanism can at the same time for several claim service, therefore the efficiency of Java Servlet is very high.But the Java Servlet also is not to has no weakness, similar to traditional CGI, ISAPI, the NSAPI method, the Java Servlet is to make use of to output the HTML language sentence to carry out the dynamic state web page of, if develop the whole website with the Java Servlet, the integration process of the dynamic state part and the static state page is an evil-foreboding dream simply. For solving this kind of weakness of the Java Servlet, the SUN released the JSP.A number of years ago, Marty was invited to attend a small 20-person industry roundtable discussion on software technology. Sitting in the seat next to Marty was James Gosling, inventor of the Java programming language. Sitting several seats away was a high-level manager from a very large software company in Redmond, Washington. During the discussion, the moderator brought up the subject of Jini, which at that time was a new Java technology. The moderator asked the manager what he thought of it, and the manager responded that it was too early to tell, but that it seemed to be an excellent idea. He went on to say that they would keep an eye on it, and if it seemed to be catching on, they would follow his company's usual "embrace and extend" strategy. At this point, Gosling lightheartedly interjected "You mean disgrace and distend."Now, the grievance that Gosling was airing was that he felt that this company would take technology from other companies and suborn it for their own purposes. But guess what? The shoe is on the other foot here. The Java community did not invent the idea of designing pages as a mixture of static HTML and dynamic code marked with special tags. For example, Cold Fusion did it years earlier. Even ASP (a product from the very software company of the aforementioned manager) popularized this approach before JSP came along and decided to jump on the bandwagon. In fact, JSP not only adopted the general idea, it even used many of the same special tags as ASP did.The JSP is an establishment at the model of Java servlets on of the expression layer technique, it makes the plait write the HTML to become more simple.Be like the SSJS, it also allows you carry the static state HTML contents and servers the script mix to put together the born dynamic state exportation. JSP the script language that the Java is the tacit approval, however, be like the ASP and can use other languages( such as JavaScript and VBScript), the norm of JSP also allows to use other languages.1.3 JSP CHARACTERISTICSIs a service according to the script language in some one language of the statures system this kind of discuss, the JSP should be see make is a kind of script language.However, be a kind of script language, the JSP seemed to be too strong again, almost can use all Javas in the JSP.Be a kind of according to text originally of, take manifestation as the central development technique, the JSP provided all advantages of the Java Servlet, and, when combine with a JavaBeans together, providing a kind of make contents and manifestation that simple way that logic separate. Separate the contents and advantage of logical manifestations is, the personnel who renews the page external appearance need not know the code of Java, and renew the JavaBeans personnel also need not be design the web page of expert in hand, can use to take the page of JavaBeans JSP to define the template of Web, to build up a from have the alike external appearance of the website that page constitute. JavaBeans completes the data to provide, having no code of Java in the template thus, this means that these templates can be written the personnel by a HTML plait to support. Certainly, can also make use of the Java Servlet to control the logic of the website, adjust through the Java Servlet to use the way of the document of JSP to separate website of logic and contents.Generally speaking, in actual engine of JSP, the page of JSP is the edit and translate type while carry out, not explain the type of. Explain the dynamic state web page development tool of the type, such as ASP, PHP3 etc., because speed etc. reason, have already can't satisfy current the large electronic commerce needs appliedly, traditional development techniques are all at to edit and translate the executive way change, such as the ASP → ASP+;PHP3 → PHP4.In the JSP norm book, did not request the procedure in the JSP code part( be called the Scriptlet) and must write with the Java definitely. Actually, have some engines of JSP are adoptive other script languages such as the EMAC- Script, etc., but actually this a few script languages also are to set up on the Java, edit and translate for the Servlet to carry out of. Write according to the norm of JSP, have no Scriptlet of relation with Java also is can of, however, mainly lie in the ability and JavaBeans, the Enterprise JavaBeanses because of the JSP strong function to work together, so even is the Scriptlet part not to use the Java, edit and translate of performance code also should is related with Java.1.4 JSP MECHANISMTo comprehend the JSP how unite the technical advantage that above various speak of, come to carry out various result easily, the customer must understand the differentiation of" the module develops for the web page of the center" and" the page develops for the web page of the center" first.The SSJS and ASP are all in several year ago to release, the network of that time is still very young, no one knows to still have in addition to making all business, datas and the expression logic enter the original web page entirely heap what better solvethe method. This kind of model that take page as the center studies and gets the very fast development easily. However, along with change of time, the people know that this kind of method is unwell in set up large, the Web that can upgrade applies the procedure. The expression logic write in the script environment was lock in the page, only passing to shear to slice and glue to stick then can drive heavy use. Express the logic to usually mix together with business and the data logics, when this makes be the procedure member to try to change an external appearance that applies the procedure but do not want to break with its llied business logic, apply the procedure of maintenance be like to walk the similar difficulty on the eggshell. In fact in the business enterprise, heavy use the application of the module already through very mature, no one would like to rewrite those logics for their applied procedure.HTML and sketch the designer handed over to the implement work of their design the Web plait the one who write, make they have to double work-Usually is the handicraft plait to write, because have no fit tool and can carry the script and the HTML contents knot to the server to put together. Chien but speech, apply the complexity of the procedure along with the Web to promote continuously, the development method that take page as the center limits sex to become to get up obviously.At the same time, the people always at look for the better method of build up the Web application procedure, the module spreads in customer's machine/ server the realm. JavaBeans and ActiveX were published the company to expand to apply the procedure developer for Java and Windows to use to come to develop the complicated procedure quickly by" the fast application procedure development"( RAD) tool. These techniques make the expert in the some realm be able to write the module for the perpendicular application plait in the skill area, but the developer can go fetch the usage directly but need not control the expertise of this realm.Be a kind of take module as the central development terrace, the JSP appeared. It with the JavaBeans and Enterprise JavaBeans( EJB) module includes the model of the business and the data logic for foundation, provide a great deal of label and a script terraces to use to come to show in the HTML page from the contents of JavaBeans creation or send a present in return. Because of the property that regards the module as the center of the JSP, it can drive Java and not the developer of Java uses equally. Not the developer of Java can pass the JSP label( Tags) to use the JavaBeans that the deluxe developer of Java establish. The developer of Java not only can establish and use the JavaBeans, but also can use the language of Java to come to control more accurately in the JSP page according to the expression logic of the first floor JavaBeans.See now how JSP is handle claim of HTTP. In basic claim model, a claimdirectly was send to JSP page in. The code of JSP controls to carry on hour of the logic processing and module of JavaBeanses' hand over with each other, and the manifestation result in dynamic state bornly, mixing with the HTML page of the static state HTML code. The Beans can be JavaBeans or module of EJBs. Moreover, the more complicated claim model can see make from is request other JSP pages of the page call sign or Java Servlets.The engine of JSP wants to chase the code of Java that the label of JSP, code of Java in the JSP page even all converts into the big piece together with the static state HTML contents actually. These codes piece was organized the Java Servlet that customer can not see to go to by the engine of JSP, then the Servlet edits and translate them automatically byte code of Java.Thus, the visitant that is the website requests a JSP page, under the condition of it is not knowing, an already born, the Servlet actual full general that prepared to edit and translate completes all works, very concealment but again and efficiently. The Servlet is to edit and translate of, so the code of JSP in the web page does not need when the every time requests that page is explain. The engine of JSP need to be edit and translate after Servlet the code end is modify only once, then this Servlet that editted and translate can be carry out. The in view of the fact JSP engine auto is born to edit and translate the Servlet also, need not procedure member begins to edit and translate the code, so the JSP can bring vivid sex that function and fast developments need that you are efficiently.Compared with the traditional CGI, the JSP has the equal advantage. First, on the speed, the traditional procedure of CGI needs to use the standard importation of the system to output the equipments to carry out the dynamic state web page born, but the JSP is direct is mutually the connection with server. And say for the CGI, each interview needs to add to add a progress to handle, the progress build up and destroy by burning constantly and will be a not small burden for calculator of be the server of Web. The next in order, the JSP is specialized to develop but design for the Web of, its purpose is for building up according to the Web applied procedure, included the norm and the tool of a the whole set. Use the technique of JSP can combine a lot of JSP pages to become a Web application procedure very expediently.JSP six built-in objectsrequest for:The object of the package of information submitted by users, by calling the object corresponding way to access the information package, namely the use of the target users can access the information.response object:The customer's request dynamic response to the client sent the data.session object1. What is the session: session object is a built-in objects JSP, it in the first JSP pages loaded automatically create, complete the conversation of management.From a customer to open a browser and connect to the server, to close the browser, leaving the end of this server, known as a conversation.When a customer visits a server, the server may be a few pages link between repeatedly, repeatedly refresh a page, the server should bethrough some kind of way to know this is the same client, which requires session object.2. session object ID: When a customer's first visit to a server on the JSP pages, JSP engines produce a session object, and assigned aString type of ID number, JSP engine at the same time, the ID number sent to the client, stored in Cookie, this session objects, and customers on the establishment of a one-to-one relationship. When a customer to connect to the server of the other pages, customers no longer allocated to the new session object, until, close your browser, the client-server object to cancel the session, and the conversation, and customer relationship disappeared. When a customer re-open the browser to connect to the server, the server for the customer to create a new session object.aplication target1. What is the application:Servers have launched after the application object, when a customer to visit the site between the various pages here, this application objects are the same, until the server is down. But with the session difference is that all customers of the application objects are the same, that is, all customers share this built-in application objects.2. application objects commonly used methods:(1) public void setAttribute (String key, Object obj): Object specified parameters will be the object obj added to the application object, and to add the subject of the designation of a keyword index.(2) public Object getAttribute (String key): access to application objects containing keywords for.out targetsout as a target output flow, used to client output data. out targets for the output data.Cookie1. What is Cookie:Cookie is stored in Web server on the user's hard drive section of the text. Cookie allow a Web site on the user's computer to store information on and then get back to it.For example, a Web site may be generated for each visitor a unique ID, and then to Cookie in the form of documents stored in each user's machine.If you use IE browser to visit Web, you will see all stored on your hard drive on the Cookie. They are most often stored in places: c: \ windows \ cookies (in Window2000 is in the C: \ Documents and Settings \ your user name \ Cookies).Cookie is "keyword key = value value" to preserve the format of the record.2. Targets the creation of a Cookie, Cookie object called the constructor can create a Cookie. Cookie object constructor has two string .parameters: Cookie Cookie name and value.Cookie c = new Cookie ( "username", "john");3. If the JSP in the package good Cookie object to send to the client, the use of the response addCookie () method.Format: response.addCookie (c)4. Save to read the client's Cookie, the use of the object request getCookies () method will be implemented in all client came to an array of Cookie objects in the form of order, to meet the need to remove the Cookie object, it is necessary to compare an array cycle Each target keywords.JSP的技术发展历史Java Server Pages(JSP)是一种基于web的脚本编程技术，类似于网景公司的服务器端Java脚本语言—— server-side JavaScript(SSJS)和微软的Active Server Pages(ASP)。

Java技术外文翻译文献(文档含中英文对照即英文原文和中文翻译)外文：Core Java™ Volume II–Advanced Features When Java technology first appeared on the scene, the excitement was not about a well-crafted programming language but about the possibility of safely executing applets that are delivered over the Internet (see V olume I, Chapter 10 for more information about applets). Obviously, delivering executable applets is practical only when the recipients are sure that the code can't wreak havoc on their machines. For this reason, security was and is a major concern of both the designers and the users of Java technology. This means that unlike other languages andsystems, where security was implemented as an afterthought or a reaction to break-ins, security mechanisms are an integral part of Java technology.Three mechanisms help ensure safety:•Language design features (bounds checking on arrays, no unchecked type conversions, no pointer arithmetic, and so on).•An access control mechanism that controls what the code can do (such as file access, network access, and so on).•Code signing, whereby code authors can use standard cryptographic algorithms to authenticate Java code. Then, the users of the code can determine exactly who created the code and whether the code has been altered after it was signed.Below, you'll see the cryptographic algorithms supplied in the java.security package, which allow for code signing and user authentication.As we said earlier, applets were what started the craze over the Java platform. In practice, people discovered that although they could write animated applets like the famous "nervous text" applet, applets could not do a whole lot of useful stuff in the JDK 1.0 security model. For example, because applets under JDK 1.0 were so closely supervised, they couldn't do much good on a corporate intranet, even though relatively little risk attaches to executing an applet from your company's secure intranet. It quickly became clear to Sun that for applets to become truly useful, it was important for users to be able to assign different levels of security, depending on where the applet originated. If an applet comes from a trusted supplier and it has not been tampered with, the user of that applet can then decide whether to give the applet more privileges.To give more trust to an applet, we need to know two things:•Where did the applet come from?•Was the code corrupted in transit?In the past 50 years, mathematicians and computer scientists have developed sophisticated algorithms for ensuring the integrity of data and for electronic signatures. The java.security package contains implementations of many of these algorithms. Fortunately, you don't need to understand the underlying mathematics to use the algorithms in the java.security package. In the next sections, we show you how message digests can detect changes in data files and how digital signatures can prove the identity of the signer.A message digest is a digital fingerprint of a block of data. For example, the so-called SHA1 (secure hash algorithm #1) condenses any data block, no matter how long, into a sequence of 160 bits (20 bytes). As with real fingerprints, one hopes that no two messages have the same SHA1 fingerprint. Of course, that cannot be true—there are only 2160 SHA1 fingerprints, so there must be some messages with the same fingerprint. But 2160is so large that the probability of duplication occurring is negligible. How negligible? According to James Walsh in True Odds: How Risks Affect Your Everyday Life (Merritt Publishing 1996), the chance that you will die from being struck by lightning is about one in 30,000. Now, think of nine other people, for example, your nine least favorite managers or professors. The chance that you and all of them will die from lightning strikes is higher than that of a forged message having the same SHA1 fingerprint as the original. (Of course, more than ten people, none of whom you are likely to know, will die from lightning strikes. However, we are talking about the far slimmer chance that your particular choice of people will be wiped out.)A message digest has two essential properties:•If one bit or several bits of the data are changed, then the message digest also changes.• A forger who is in possession of a given message cannot construct a fake message that has the same message digest as the original.The second property is again a matter of probabilities, of course. Consider the following message by the billionaire father:"Upon my death, my property shall be divided equally among my children; however, my son George shall receive nothing."That message has an SHA1 fingerprint of2D 8B 35 F3 BF 49 CD B1 94 04 E0 66 21 2B 5E 57 70 49 E1 7EThe distrustful father has deposited the message with one attorney and the fingerprint with another. Now, suppose George can bribe the lawyer holding the message. He wants to change the message so that Bill gets nothing. Of course, that changes the fingerprint to a completely different bit pattern:2A 33 0B 4B B3 FE CC 1C 9D 5C 01 A7 09 51 0B 49 AC 8F 98 92Can George find some other wording that matches the fingerprint? If he had been the proud owner of a billion computers from the time the Earth was formed, each computing a million messages a second, he would not yet have found a message he could substitute.A number of algorithms have been designed to compute these message digests. The two best-known are SHA1, the secure hash algorithm developed by the National Institute of Standards and Technology, and MD5, an algorithm invented by Ronald Rivest of MIT. Both algorithms scramble the bits of a message in ingenious ways. For details about these algorithms, see, for example, Cryptography and Network Security, 4th ed., by William Stallings (Prentice Hall 2005). Note that recently, subtle regularities have been discovered in both algorithms. At this point, most cryptographers recommend avoiding MD5 and using SHA1 until a stronger alternative becomes available.The Java programming language implements both SHA1 and MD5. The MessageDigest class is a factory for creating objects that encapsulate the fingerprinting algorithms. It has a static method, called getInstance, that returns an object of a class that extends the MessageDigest class. This means the MessageDigest class serves double duty:•As a factory class•As the superclass for all message digest algorithmsFor example, here is how you obtain an object that can compute SHA fingerprints:MessageDigest alg = MessageDigest.getInstance("SHA-1");(To get an object that can compute MD5, use the string "MD5" as the argument to getInstance.)After you have obtained a MessageDigest object, you feed it all the bytes in the message by repeatedly calling the update method. For example, the following code passes all bytes in a file to the alg object just created to do the fingerprinting：InputStream in = . . .int ch;while ((ch = in.read()) != -1)alg.update((byte) ch);Alternatively, if you have the bytes in an array, you can update the entire array at once:byte[] bytes = . . .;alg.update(bytes);When you are done, call the digest method. This method pads the input—as required by the fingerprinting algorithm—does the computation, and returns the digest as an array of bytes.byte[] hash = alg.digest();The program in Listing 9-15 computes a message digest, using either SHA or MD5. You can load the data to be digested from a file, or you can type a message in the text area.Message SigningIn the last section, you saw how to compute a message digest, a fingerprint for the original message. If the message is altered, then the fingerprint of the altered message will not match the fingerprint of the original. If the message and its fingerprint are delivered separately, then the recipient can check whether the message has been tampered with. However, if both the message and the fingerprint were intercepted, it is an easy matter to modify the message and then recompute the fingerprint. After all, the message digest algorithms are publicly known, and they don't require secret keys. In that case, the recipient of the forged message and the recomputed fingerprint would never know that the message has been altered. Digital signatures solve this problem.To help you understand how digital signatures work, we explain a few concepts from the field called public key cryptography. Public key cryptography is based on the notion of a public key and private key. The idea is that you tell everyone in the world your public key. However, only you hold the private key, and it is important that you safeguard it and don't release it to anyone else. The keys are matched by mathematical relationships, but the exact nature of these relationships is not important for us.The keys are quite long and complex. For example, here is a matching pair of public and private Digital Signature Algorithm (DSA) keys.Public key:Code View:p:fca682ce8e12caba26efccf7110e526db078b05edecbcd1eb4a208f3ae1617ae01f35b91a47e6df 63413c5e12ed0899bcd132acd50d99151bdc43ee737592e17q: 962eddcc369cba8ebb260ee6b6a126d9346e38c5g:678471b27a9cf44ee91a49c5147db1a9aaf244f05a434d6486931d2d14271b9e35030b71fd7 3da179069b32e2935630e1c2062354d0da20a6c416e50be794ca4y:c0b6e67b4ac098eb1a32c5f8c4c1f0e7e6fb9d832532e27d0bdab9ca2d2a8123ce5a8018b8161 a760480fadd040b927281ddb22cb9bc4df596d7de4d1b977d50Private key:Code View:p:fca682ce8e12caba26efccf7110e526db078b05edecbcd1eb4a208f3ae1617ae01f35b91a47e6df 63413c5e12ed0899bcd132acd50d99151bdc43ee737592e17q: 962eddcc369cba8ebb260ee6b6a126d9346e38c5g:678471b27a9cf44ee91a49c5147db1a9aaf244f05a434d6486931d2d14271b9e35030b71fd73 da179069b32e2935630e1c2062354d0da20a6c416e50be794ca4x: 146c09f881656cc6c51f27ea6c3a91b85ed1d70aIt is believed to be practically impossible to compute one key from the other. That is, even though everyone knows your public key, they can't compute your private key in your lifetime, no matter how many computing resources they have available.It might seem difficult to believe that nobody can compute the private key from the public keys, but nobody has ever found an algorithm to do this for the encryption algorithms that are in common use today. If the keys are sufficiently long, brute force—simply trying all possible keys—would require more computers than can be built from all the atoms in the solar system, crunching away for thousands of years. Of course, it is possible that someone could come up with algorithms for computing keys that are much more clever than brute force. For example, the RSA algorithm (the encryption algorithm invented by Rivest, Shamir, and Adleman) depends on the difficulty of factoring large numbers. For the last 20 years, many of the best mathematicians have tried to come up with good factoring algorithms, but so far with no success. For that reason, most cryptographers believe that keys with a "modulus" of 2,000 bits or more are currently completely safe from any attack. DSA is believed to be similarly secure.Figure 9-12 illustrates how the process works in practice.Suppose Alice wants to send Bob a message, and Bob wants to know this message came from Alice and not an impostor. Alice writes the message and then signs the message digest with her private key. Bob gets a copy of her public key. Bob then applies the public key to verify thesignature. If the verification passes, then Bob can be assured of two facts:•The original message has not been altered.•The message was signed by Alice, the holder of the private key that matches the public key that Bob used for verification.You can see why security for private keys is all-important. If someone steals Alice's private key or if a government can require her to turn it over, then she is in trouble. The thief or a government agent can impersonate her by sending messages, money transfer instructions, and so on, that others will believe came from Alice.The X.509 Certificate FormatTo take advantage of public key cryptography, the public keys must be distributed. One of the most common distribution formats is called X.509. Certificates in the X.509 format are widely used by VeriSign, Microsoft, Netscape, and many other companies, for signing e-mail messages, authenticating program code, and certifying many other kinds of data. The X.509 standard is part of the X.500 series of recommendations for a directory service by the international telephone standards body, the CCITT.The precise structure of X.509 certificates is described in a formal notation, called "abstract syntax notation #1" or ASN.1. Figure 9-13 shows the ASN.1 definition of version 3 of the X.509 format. The exact syntax is not important for us, but, as you can see, ASN.1 gives a precise definition of the structure of a certificate file. The basic encoding rules, or BER, and a variation, called distinguished encoding rules (DER) describe precisely how to save this structure in a binary file. That is, BER and DER describe how to encode integers, character strings, bit strings, and constructs such as SEQUENCE, CHOICE, and OPTIONAL.译文：Java核心技术卷Ⅱ高级特性当Java技术刚刚问世时，令人激动的并不是因为它是一个设计完美的编程语言，而是因为它能够安全地运行通过因特网传播的各种applet。

比较好的双语版软件开发相关的书双语版软件开发相关的书，是指那些内容既有英文，又有中文翻译的软件开发领域的书籍。

这类书籍不仅有助于提升读者的英文水平，还能对软件开发领域有深入的了解和学习。

在本文中，我们将探讨几本比较好的双语版软件开发相关的书籍，并分析它们的特点和价值。

1.《深入理解计算机系统》这本书是经典的计算机系统原理教材，作者是Randal E. Bryant和David R. O'Hallaron。

它详细讲解了计算机系统的各个层次，包括硬件、操作系统和编译器等。

书中的案例和实例都非常具体和实用。

该书的双语版简体中文和英文对照，可以帮助读者更好地理解和学习计算机系统的知识，尤其适合想要深入了解计算机系统原理的读者。

2.《Head First设计模式》这是一本经典的设计模式教材，作者是Eric Freeman和Elisabeth Robson。

该书以生动活泼的方式介绍了23种常用的设计模式，并通过大量的例子和练习帮助读者理解和应用这些设计模式。

书中的双语版简体中文和英文对照，可以帮助读者更好地掌握设计模式的概念和应用方法，对于想要提升软件设计能力的开发者非常有帮助。

3.《Java编程思想》这本书是Java编程领域的经典教材，作者是Bruce Eckel。

书中系统地介绍了Java语言的各个方面，包括语法、面向对象、集合框架、并发编程等。

该书的双语版简体中文和英文对照，可以帮助读者更好地学习和掌握Java编程语言，适合想要系统地学习Java语言的开发者。

总结回顾：通过以上几本双语版软件开发相关的书籍的介绍，我们可以看到这类书籍的优势和价值。

双语版的设计可以帮助读者更好地理解和学习书中的知识，尤其对于英文水平较弱的读者来说更是如此。

另外，这类书籍往往是经典的教材或权威的专著，其内容丰富、权威性强，对于提升软件开发能力是非常有帮助的。

选择一些好的双语版软件开发相关的书籍来学习，可以帮助我们更全面、深入和灵活地理解和掌握软件开发领域的知识。

软件工程毕业论文文献翻译中英文对照学生毕业设计(论文)外文译文学生姓名: 学号专业名称:软件工程译文标题(中英文):Qt Creator白皮书(Qt Creator Whitepaper)译文出处:Qt network 指导教师审阅签名: 外文译文正文:Qt Creator白皮书Qt Creator是一个完整的集成开发环境(IDE)，用于创建Qt应用程序框架的应用。

Qt是专为应用程序和用户界面，一次开发和部署跨多个桌面和移动操作系统。

本文提供了一个推出的Qt Creator和提供Qt开发人员在应用开发生命周期的特点。

Qt Creator的简介Qt Creator的主要优点之一是它允许一个开发团队共享一个项目不同的开发平台(微软Windows?的Mac OS X?和Linux?)共同为开发和调试工具。

Qt Creator的主要目标是满足Qt开发人员正在寻找简单，易用性，生产力，可扩展性和开放的发展需要，而旨在降低进入新来乍到Qt的屏障。

Qt Creator 的主要功能，让开发商完成以下任务: , 快速，轻松地开始使用Qt应用开发项目向导，快速访问最近的项目和会议。

, 设计Qt物件为基础的应用与集成的编辑器的用户界面，Qt Designer中。

, 开发与应用的先进的C + +代码编辑器，提供新的强大的功能完成的代码片段，重构代码，查看文件的轮廓(即，象征着一个文件层次)。

, 建立，运行和部署Qt项目，目标多个桌面和移动平台，如微软Windows，Mac OS X中，Linux的，诺基亚的MeeGo，和Maemo。

, GNU和CDB使用Qt类结构的认识，增加了图形用户界面的调试器的调试。

, 使用代码分析工具，以检查你的应用程序中的内存管理问题。

, 应用程序部署到移动设备的MeeGo，为Symbian和Maemo设备创建应用程序安装包，可以在Ovi商店和其他渠道发布的。

, 轻松地访问信息集成的上下文敏感的Qt帮助系统。

学校代码： 10128学号：本科毕业设计外文文献翻译二〇一五年一月The Test Library Management System ofFramework Based on SSHThe application system features in small or medium-sized enterprise lie in the gre ater flexibility and safety high performance-price ratio. Traditional J2EE framework c an not adapt to these needs, but the system application based on SSH(Struts+Spring+ Hibernate) technology can better satisfy such needs. This paper analyses some integra tion theory and key technologies about SSH, and according to the integration construc ts a lightweight WEB framework, which has integrated the three kinds of technology , forming the lightweight WEB framework based on SSH and gaining good effects in p ractical applications.IntroductionGenerally the J2EE platform[27] used in large enterprise applications, can well s olve the application of reliability, safety and stability, but its weakness is the price hig h and the constructing cycle is long. Corresponding to the small or medium enterprise applications, the replace approach is the system framework of lightweight WEB, inclu ding the more commonly used methods which are based on the Struts and Hibernate. With the wide application of Spring, the three technology combination may be a bette r choice as a lightweight WEB framework. It uses layered structure and provides a go od integrated framework for Web applications at all levels in minimizing the Interlaye r coupling and increasing the efficiency of development. This framework can solve a l ot of problems, with good maintainability and scalability. It can solve the separation o f user interface and business logic separation, the separation of business logic and data base operation and the correct procedure control logic, etc. This paper studies the tech nology and principle of Struts and Spring and Hibernate, presenting a proved lightwei ght WEB application framework for enterprise.Hierarchical Web MechanismHierarchical Web framework including the user presentation layer, business logic layer, data persistence layer ,expansion layer etc, each layer for different function, res pectively to finish the whole application. The whole system are divided into different logic module with relatively independent and mutual, and each module can be implem ented according to different design. It can realize the system parallel development, rap id integration, good maintainability, scalability.Struts MVC FrameworkTo ensure the reuse and efficiency of development process, adopting J2EE techn ology to build the Web application must select a system framework which has a good performance . Only in this way can we ensure not wasting lots of time because of adju sting configuration and achieve application development efficiently and quickly. So, p rogrammers in the course of practice got some successful development pattern which proved practical, such as MVC and O/R mapping, etc; many technologies, including S truts and Hibernate frameworks, realized these pattern. However, Struts framework on ly settled the separation problem between view layer and business logic layer, control layer, did not provide a flexible support for complex data saving process. On the contr ary, Hibernate framework offered the powerful and flexible support for complex data saving process. Therefore, how to integrate two frameworks and get a flexible, low-co upling solutions project which is easy to maintain for information system, is a researc h task which the engineering staff is studying constantly.Model-View-Controller (MVC) is a popular design pattern. It divides the interact ive system in three components and each of them specializes in one task. The model c ontains the application data and manages the core functionality. The visual display of t he model and the feedback to the users are managed by the view. The controller not o nly interprets the inputs from the user, but also dominates the model and the view to c hange appropriately. MVC separates the system functionality from the system interfac e so as to enhance the system scalability and maintainability. Struts is a typical MV C frame[32], and it also contains the three aforementioned components. The model le vel is composed of JavaBean and EJB components. The controller is realized by actio n and ActionServlet, and the view layer consists of JSP files. The central controller co ntrols the action execution that receives a request and redirects this request to the appr opriate module controller. Subsequently, the module controller processes the request a nd returns results to the central controller using a JavaBean object, which stores any object to be presented in the view layer by including an indication to module views that must be presented. The central controller redirects the returned JavaBean object to th e main view that displays its information.Spring Framework technologySpring is a lightweight J2EE application development framework, which uses the model of Inversion of Control(IoC) to separate the actual application from the Config uration and dependent regulations of the application. Committed to J2EE application a t all levels of the solution, Spring is not attempting to replace the existing framework, but rather “welding” the object of J2EE application at all levels together through the P OJO management. In addition, developers are free to choose Spring framework for so me or all, since Spring modules are not totally dependent.As a major business-level detail, Spring employs the idea of delay injection to as semble code for the sake of improving the scalability and flexibility of built systems. Thus, the systems achieve a centralized business processing and reduction of code reu se through the Spring AOP module.Hibernate Persistent FrameworkHibernate is a kind of open source framework with DAO design patterns to achie ve mapping(O/R Mapping) between object and relational database.During the Web system development, the tradition approach directly interacts wit h the database by JDBC .However, this method has not only heavy workload but also complex SQL codes of JDBC which need to revise because the business logic sli ghtly changes. So, whatever development or maintain system are inconvenient. Consi dering the large difference between the object-oriented relation of java and the structu re of relational database, it is necessary to introduce a direct mapping mechanism bet ween the object and database, which this kind of mapping should use configuration fil es as soon as possibility, so that mapping files will need modifying rather than java so urce codes when the business logic changes in the future. Therefore, O/R mapping pat tern emerges, which hibernate is one of the most outstanding realization of architectur e.It encapsulates JDBC with lightweight , making Java programmer operate a relati onal database with the object oriented programming thinking. It is a a implementation technology in the lasting layer. Compared to other lasting layer technology such as JD BC, EJB, JDO, Hibernate is easy to grasp and more in line with the object-oriented pr ogramming thinking. Hibernate own a query language (HQL), which is fully object-or iented. The basic structure in its application as shown in figure6.1.Hibernate is a data persistence framework, and the core technology is the object / relational database mapping(ORM). Hibernate is generally considered as a bridge bet ween Java applications and the relational database, owing to providing durable data se rvices for applications and allowing developers to use an object-oriented approach to t he management and manipulation of relational database. Furthermore, it furnishes an object-oriented query language-HQL.Responsible for the mapping between the major categories of Java and the relatio nal database, Hibernate is essentially a middle ware providing database services. It su pplies durable data services for applications by utilizing databases and several profiles , such as hibernate properties and XML Mapping etc..Web services technologiesThe introduction of annotations into Java EE 5 makes it simple to create sophisticated Web service endpoints and clients with less code and a shorter learning curve than was possible with earlier Java EE versions. Annotations — first introduced in Java SE 5 — are modifiers you can add to your code as metadata. They don't affect program semantics directly, but the compiler, development tools, and runtime libraries can process them to produce additional Java language source files, XML documents, or other artifacts and behavior that augment the code containing the annotations (see Resources). Later in the article, you'll see how you can easily turn a regular Java class into a Web service by adding simple annotations.Web application technologiesJava EE 5 welcomes two major pieces of front-end technology — JSF and JSTL —into the specification to join the existing JavaServer Pages and Servletspecifications. JSF is a set of APIs that enable a component-based approach to user-interface development. JSTL is a set of tag libraries that support embedding procedural logic, access to JavaBeans, SQL commands, localized formatting instructions, and XML processing in JSPs. The most recent releases of JSF, JSTL, and JSP support a unified expression language (EL) that allows these technologies to integrate more easily (see Resources).The cornerstone of Web services support in Java EE 5 is JAX-WS 2.0, which is a follow-on to JAX-RPC 1.1. Both of these technologies let you create RESTful and SOAP-based Web services without dealing directly with the tedium of XML processing and data binding inherent to Web services. Developers are free to continue using JAX-RPC (which is still required of Java EE 5 containers), but migrating to JAX-WS is strongly recommended. Newcomers to Java Web services might as well skip JAX-RPC and head right for JAX-WS. That said, it's good to know that both of them support SOAP 1.1 over HTTP 1.1 and so are fully compatible: a JAX-WS Web services client can access a JAX-RPC Web services endpoint, and vice versa.The advantages of JAX-WS over JAX-RPC are compelling. JAX-WS:•Supports the SOAP 1.2 standard (in addition to SOAP 1.1).•Supports XML over HTTP. You can bypass SOAP if you wish. (See the article "Use XML directly over HTTP for Web services (where appropriate)" for more information.)•Uses the Java Architecture for XML Binding (JAXB) for its data-mapping model. JAXB has complete support for XML schema and better performance (more on that in a moment).•Introduces a dynamic programming model for both server and client.The client model supports both a message-oriented and an asynchronous approach.•Supports Message Transmission Optimization Mechanism (MTOM), a W3C recommendation for optimizing the transmission and format of a SOAPmessage.•Upgrades Web services interoperability (WS-I) support. (It supports Basic Profile 1.1; JAX-WS supports only Basic Profile 1.0.)•Upgrades SOAP attachment support. (It uses the SOAP with Attachments API for Java [SAAJ] 1.3; JAX-WS supports only SAAJ 1.2.)•You can learn more about the differences by reading the article "JAX-RPC versus JAX-WS."The wsimport tool in JAX-WS automatically handles many of the mundane details of Web service development and integrates easily into a build processes in a cross-platform manner, freeing you to focus on the application logic that implements or uses a service. It generates artifacts such as services, service endpoint interfaces (SEIs), asynchronous response code, exceptions based on WSDL faults, and Java classes bound to schema types by JAXB.JAX-WS also enables high-performing Web services. See Resources for a link to an article ("Implementing High Performance Web Services Using JAX-WS 2.0") presenting a benchmark study of equivalent Web service implementations based on the new JAX-WS stack (which uses two other Web services features in Java EE 5 —JAXB and StAX) and a JAX-RPC stack available in J2EE 1.4. The study found 40% to 1000% performance increases with JAX-WS in various functional areas under different loads.ConclusionEach framework has its advantages and disadvantages .Lightweight J2EE struc ture integrates Struts and Hibernate and Spring technology, making full use the power ful data processing function of Struts and the management flexible of Spring and the mature of Hibernate. According to the practice, putting forward anopen-source solutions suitable for small or medium-sized enterprise application of. Th e application system based on this architecture technology development has interlayer loose coupling ,structure distinctly, short development cycle, maintainability. In addition, combined with commercial project development, the solution has achieved good effect. The lightweight framework makes the parallel development and maintenance f or commercial system convenience, and can push forward become other industry busi ness system development.Through research and practice, we can easily find that Struts / Spring / Hiberna te framework utilizes Struts maturity in the presentation layer, flexibility of Spring bu siness management and convenience of Hibernate in the serialization layer, three kind s of framework integrated into a whole so that the development and maintenance beca me more convenient and handy. This kind of approach also will play a key role if appl ying other business system. Of course ,how to optimize system performance, enhance the user's access speed, improve security ability of system framework ,all of these wor ks, are need to do for author in the further.基于SSH框架实现的试题库管理系统小型或者中型企业的应用系统具有非常好的灵活性、安全性以及高性价比，传统的J2EE架构满足不了这些需求，但是基于SSH框架实现的应用系统更好的满足了这样的需求，这篇文章分析了关于SSH的一体化理论和关键技术，通过这些集成形成了轻量级Web框架，在已经集成三种技术的基础上，伴随形成了基于SSH的轻量级Web 框架，并且在实际应用中有着重要作用。

中英文对照外文翻译外文资料原文Software Development Concepts and DesignMethodologiesDuring the 1960s, ma inframes and higher level programming languages were applied to man y problems including human resource s yste ms,reservation s yste ms, and manufacturing s yste ms. Computers and software were seen as the cure all for man y bu siness issues were sometimes applied blindly. S yste ms sometimes failed to solve the problem for which the y were designed for man y reasons including:•Inability to sufficiently understand complex problems•Not sufficiently taking into account end-u ser needs, the organizational environ ment, and performance tradeoffs•Inability to accurately estimate development time and operational costs •Lack of framework for consistent and regular customer commun ications At this time, the concept of structured programming, top-down design, stepwise refinement，and modularity e merged. Structured programming is still the most dominant approach to software engineering and is still evo lving. These failures led to the c oncept of "software engineering" based upon the idea that an engineering-like discipline could be applied to software design and develop ment.Software design is a process where the software designer applies techniques and principles to produce a conceptual model that de scribes and defines a solution to a problem. In the beginning, this design process has not been well structured and the model does not alwa ys accurately represent theproblem of software development. However,design methodologies have been evolving to accommo date changes in technolog y coupled with our increased understanding of development processes.Whereas early desig n methods addressed specific aspects of the develop ment process, current methods atte mpt to address the entire scope of software development. Software design methods are often classified in reference to the period in which the y were introduced and the problems at that time. Driven b y coding and testing problems, tools and methods were developed. Early methods focused on modularit y a nd top-down development, and information hiding through abstraction. This led to the development of structured languages, structured analysis, and data flow analysis.In the last decade or so, the expense involved in automation has shifted from hardware to people. Therefore, the software engineering community has been focused on object oriented (O-O) design and the concept of re-usable code in order to reduce the human cost component. Inefficient designs and develop ment methodologies have been addressed with Computer Aided Software Engineering (CASE) tools, and fourth generation design languages. This has been done in an attempt replace the traditional waterf all life c ycle process model under which most existing software has been developed.一、Software De sign FundamentalsSoftware design meth ods all aim to provide the software designer with a s yste m blueprint. This blueprint usually has three aspects: data, architectural, and procedural.•Data design refers to the data's organization, relationships, access and processing methods.•Architectural design defines the components of the sys tem a nd their relationships.•Procedural design builds on the data and architectural design phases to describe the processing details of the s yste m.Even though there are numer ous design methodologies, their basicconcepts are ver y similar-All software design methods partition the problem and software into smaller pieces in order to reduce complexity. They all strive to identif y data structures and functions, and provide measur e ments for software quality. Some of the common principles in software design include: stepwise refinement, s oftware architecture, program structure, data structure, software procedures, mo d u la r i t y,a b s tr a c t io n,a n d in f o r ma t io n h i d i n g.二、M o d e r n D e s i g n M e t h o d o l o g i e sC o n ve n t io n a l s o f t wa r e d e ve l o p me n t p r a c t ic e s c a n g e n e r a l l y b ema p p e d o n to t h e tr a d i t io n a l l i f e-c y c l e p h a s e s o f a n a l ys i s,f u n c t i o n a ls p e c i f i c a t i o n,d e s i g n,i mp l e me n t a t i o n,t e s t i n g,a n d m a i n t e n a n c e.T h i st h o u g h t p r o c e s s i s i n a d e q u a t e f o r t o d a y's c o m p l e x i n f o r m a t i o n s y s t e m s.As the demand for software is growing much faster than the number of developers, adhering to conventional techniques such as the waterfall method requires too much time, too many people, and is difficult to manage. Hence, many new software development technologies have arisen. N e wl y d e ve lo p e d p r a c tic e s a n d mo d e ls d o n o t a tte mp t to s e p a r a te p h a s e s o f s o f twa r e development, such as specification and implementation, but instead focus on the concept of program transformation through stepwise refinement and iteration.1、O b j e c t-O r i e n t e d Te c h n o l o g yObject-Oriented (O-O) software design technology is fundamentally different from the traditional methods described above. With traditional methods, each module is recognized a major step in the o verall process and the process goes from one step to the next. On the other hand, O-O design is structured around a model of objects and the functions they perform.O-O programming can be traced to the simulation language SIMULA, a high level language developed in the late 60's that introduced object classes as a method to encapsulate data. Later, in the 1970s, Smalltalk was introduced as a complete graphic user interface (GUI) environment for O-O programming. Even 30 years later, Smalltalk is still the sta ndard against which all other O-O languages are measured. O-O software development methodologies have becomepopular in the last decade as O-O concepts have matured. At the same time, the software industry's focus has shifted from coding and structured pro cesses to saving labor costs, and time through design and flexibility. Flexibility has become pivotal because sys tems have become larger, more complex, and more volatile with rapidly changing requirements.With O-O, there is no real separation between anal ysis and design. During analysis, system objects are identified along with their characteristics and relationships. These objects are maintained through design and coding as detail is added to the design. This provides a common language throughout each sta ge in development. O-O is best applied with specifically designed O-O development tools, but it is important to remember that as a methodology is it not specific to any programming language. Many different programming languages can be used to implement 0-0 technology and design methodologies.Instead of procedures and functions passing data back and forth, in object oriented design, the system is viewed as a collection of objects with messages passed from object to object. Each object has its own set of ass ociated operations. Object-oriented design is based on the idea of information hiding and modularization of both data and processing. It is best used when neither data structure nor processing operations are well defined ahead of time. This is quite useful in today's business environment where requirements are always changing and not very well defined. Thus, it has become quite popular! The concept of objects performing services is a natural way of thinking for both developers and customers. This facilitate s understanding the problem domain and a more natural design. In addition, there are many benefits of object-oriented development. These include:•I n h e r i t a n c e c a p i t a l i z e s o n t h e c o m m o n a l t y o f a t t r i b u t e s a n d s e r v i c e s a l l o w i n g c o d e a n d objects to be re-used..I n f o r m a t i o n h i d i n g m a k e s s y s t e m s m o r e s t a b l e b y l o c a l i z i n g c h a n g e s t o o b j e c t s a n d t h e r e b y m a k i n g t h e m r e u s a b l e..T h e o b j e c t-o r i e n t e d d e v e l o p m e n t p r o c e s s i s c o n s i s t e n t f r o ma n a l y s i s,t h r o u g h d e s i g n, t o c o d i n g.More information on Object Oriented Programm ing principles can be found in Chapter 4-Organization of Programming Languages and Programming Concepts.2、P r o t o t y p i n gPrototyping was invented because end users participating in the development phase found it difficult to understand requirement specifica tions and conceptual models. However, when it first began being used in the 1980s, most conventional life c ycle developers considered it expensive and time consuming.S i n c e t h a t t i m e,u s e r s a n d d e v e l o p e r s h a v e u s e d p r o t o t y p e s s u c c e s s f u l l y a s a communications tool to demonstrate system requirements. After several prototype iterations, developers have a better understanding of user requirements and users have a better idea of how the s ystem will eventually work, look, and feel. Prototyping has proven to be an effective way of understanding the users' needs and problems and eliminating costly rework later in the development process due to misunderstandings in requirements. Prototyping is particularly useful for user interface development because it is sometimes impossible to represent the look and feel of a user interface in an effective way using words and diagrams. This is especially critical in today's development environment where user interface development consumes an increasing portion of overall system de velopment costs.（1）T h r o w Aw a y P r o to t yp in gThere are two va r ieties of pro to typ ing, Th row-awa y p ro to typin g and Evo lutiona r y prototyping. Throw-away prototyping is designed to validate or derive the system requirements. It may also be used to evaluate performan ce capabilities and determine design feasibility. Once the desired information has been obtained and the prototype's objective has been fulfilled, the p r o t o t y p e i s t h r o w n a w a y a n d c o n v e n t i o n a l s o f t w a r e d e s i g n c o n t i n u e s.T h r o w a w a y p r o t o t y p i n g are:•U s e d t o r e d u c e r e q u i r e m e n t s r i s k a n d f a c i l i t a t e u n d e r s t a n d i n gu s e r r e q u i r e m e n t s.•N o t c o n s i d e r e d a s a f i n a l s y s t e m,a n d i s d i s c a r d e d a f t e r u s eb ec a u s e:♦M a n y s y s t e m c h a r a c t e r i s t i c s a r e l e f t o u t♦T h e p r o t o t y p e i s w r i t t e n q u i c k l y p r i m a r i l y f o r t h e p u r p o s e o f d e m o n s t r a t i o n a n d t h e r e f o r e m a y n o t b e o p t i m a l l ys t r u c t u r e d a n d c o n s e q u e n t l y d i f f i c u l t t o m a i n t a i n With th r o w a wa y p r o to t yp in g,s o me a n a l ys ts th in k o f a p r o to t y p e a s a d e s ig n o r specifications language to be used as input to the traditional system design phase, rather than a product or system in itself.（2）Evol uti onary PrototypingR a t h e r t h a n b e i n g d e s i g n e d t o w i t h t h e i n t e n t i o n o f b e i n g t h r o w n a w a y,e v o l u t i o n a r y p r o t o t y p i n g d e l i v e r s a w o r k i n g s y s t e m t o e n d-u s e r s. T h e d e v e l o p m e n t s t a r t s w i t h t h o s e r e q u i r e me n ts t h a t a r e b e s t u n d e r s to o d. T h e n,r a th e r th a n b e in g a p r e l i mi n a r y s t e p to th e li f e c yc le m o d e l,t h e p r o t o t y p e i s t h e c e n t r a l f o c u s o f t h e p r o c e s s m o d e l.T h e p r o t o t y p e i s s c o p e d,s c h e d u l e d a n d s p e c i f i e d.I t i s t h e n i n c r e m e n t a l l y r e f i n e d a n d u p d a t e d a s t h e c e n t r a l c o m p o n e n t o f th e p r o c e s s mo d e l.T h e n u mb e r o f t i me s th e p r o to t yp e is in c r e me n t a l l y r e f in e d d e p e n d s o n h o w we l l th e u s e r r e q u i r e me n ts a n d u n d e r s t o o d.I t a ls o d e p e n d s o n th e u s e r s n e e d to a d d r e q u ir e me n ts o r c h a n g e p r e v i o u s l y s t a t e d r e q u i r e m e n t s.A f t e r e s t a b l i s h i n g a n o v e r a l l a r c h i t e c t u r e a n d f r a me w o r k, t h e s ys t e m i s d e v e l o p e d a n d d e l i v e r e d in in c r e me n ts.U s e r s ma y e x p e r i me n t w i t h a n d u s e d e l i v e r e d i n c r e me n t s w h i l e o t h e r s a r e b e i n g d e v e l o p e d.Fo r i n s t a n c e,t h e f i r s t p r o t o t yp e ma y b e d e l i v e r e d t h a t i m p l e m e n t s a c e r t a i n s c r e e n w i t h o n l y s o m e a c t i v e m e n u i t e m s.W h i l e u s e r s a r e e x p e r i me n t i n g w i t h t h i s s c r e e n a n d me n u i t e ms,o t h e r s c r e e n s a n d me n u i t e ms a r e c o n c u r r e n t l y b e in gd e v e l o p e d wh i c h la t e r w il l b e c o mb in e d w i th th e e x is t in g p r o to t yp e a s ite vo l v e s.O n c e t h e u s e r i s s a t i s f i e d t h a t t h e p r o t o t y p e m e e t s r e q u i r e m e n t s,t h ep r o t o t y p e i s t r a n s f o r me d i n to th e"s ys t e m".T h i s e ff o r t d e p e n d s o n s e v e r a l f a c to r s. I t ma y i n c lu d e a d d i n g f u n c t i o n a l i t y t h a t w a s n't i n i t i a l l y r e c o g n i z e d a s r e q u i r e d,r e p l a c i n g i n e f f i c i e n t p a r t s o f t h e p r o t o t yp e t o me e t p e r f o r ma n c e c r i t e r i a,o r a d a p t i n g t h e p r o t o t yp e t o f i t t h e u s e r's h a r d w a r e e n vi r o n me n t.P r o t o t y p i n g c a n b e g i n v e r y e a r l y, a f t e r s o m e p r e l i m i n a r y r e q u i r e m e n t s a n a l y s i s h a s d e t e r m i n e d t h e b a s i c f u n c t i o n a l i t y,s c o p e,a n d e n v i r o n m e n t o f t h e p r o p o s e d s o f t w a r e.C o n t r a r y t o t h e t r a d i t i o n a l w a t e r f a l l me t h o d,i n t h e p r o t o t yp i n g,f u n c t i o n a l s p e c i f i c a t i o n s a r e n o t f i x e d.R a t h e r,u s e r s a r e e n c o u r a g e d t o m o d i f y t h e i r r e q u i r e m e n t s a s t h e y t h e m s e l v e s b e g i n t o u n d e r s t a n d t h e m b e t t e r.T h i s i s b e c a u s e u s e r s o f t e n d o n't r e a l l y k n o w w h a t t h e y w a n t u n t i l t h e y s e e i t o n t h e s c r e e n.T h e p r o t o t yp i n g p r o c e s s o f d e mo n s t r a t i o n,r e v i e w,a n d r e f i n e me n t g e t s t h e u s e r m o r e i n v o l v e d i n t h e d e v e l o p m e n t p r o c e s s,g i v i n g t h e m a s e n s e o f o w n e r s h i p d u r i n g t h e p r o c e s s a n d a t f i n a l s y s t e m d e l i v e r y.H o w e v e r,d u e t o t h e m i n d s e t o f"p r o t o t y p e", u s e r s o f t e n f in d i t d iff ic u l t to ve r if y t h a t th e p r o to t yp e s a tis f ie s th e ir r e q u ir e me n ts. T h e r e f o r e, g u id e l in e s mu s t b e e s t a b l i s h e d t o d e te r m in e wh e n t o s to p i te r a t in g a n d th e p r o to t yp e to f in a l p r o d u c t.外文资料译文软件开发概念和设计方法在20世纪60年代，大型机和高级程序语言被用来解决包括人力资源系统、专有系统和制造系统等许多问题。