附件1：外文资料翻译译文
Struts——一种开源MVC的实现
这篇文章介绍Struts，一个使用servlet 和JavaServer Pages 技术的一种Model-View-Controller 的实现。Struts 可以帮助你控制Web 项目中的变化并提高专业化。即使你可能永远不会用Struts实现一个系统，你可以获得一些想法用于你未来的servlet 和JSP 网页的实现中。
简介
在小学校园里的小孩子们都可以在因特网上发布HTML 网页。然而，有一个重大的不同在一个小学生和一个专业人士开发的网站之间。网页设计师（或者HTML开发人员）必须理解颜色、用户、生产流程、网页布局、浏览器兼容性、图像创建、JavaScript 等等。设计漂亮的网站需要做大量的工作，大多数Java 开发人员更注重创建优美的对象接口，而不是用户界面。JavaServer Pages (JSP) 技术为网页设计人员和Java 开发人员提供了一种联系钮带。
如果你开发过大型Web 应用程序，你就理解“变化”这个词语。“模型-视图-控制器”(MVC) 就是用来帮助你控制变化的一种设计模式。MVC 减弱了业务逻辑接口和数据接口之间的耦合。Struts 是一种MVC 实现，它将Servlet 2.2 和JSP 1.1 标记（属于J2EE 规范）用作实现的一部分。你可能永远不会用Struts 实现一个系统，但了解一下Struts 或许使你能将其中的一些思想用于你以后的Servlet和JSP 实现中。
模型-视图-控制器 (MVC)
JSP标签只解决了我们问题中的一部分。我们依然有验证、流控制、以及更新应用程序结构的问题。这就是MVC从哪儿来以及来干嘛的。MVC通过把问题分成三类来帮助解决一些与单模块相关的问题：
?Model（模型）
模块包括应用程序功能的核心。模型封装着应用程序的各个结构。有时它所包含的唯一功能就是结构。它对于视图或者控制器一无所知。
?View（视图）
视图提供了模型的演示。它是应用程序的外表。视图可以进入模型获得者，但是它对于设置者一无所知。除此之外，它对于控制器也是一无所知。视图仅仅当模型发生改变的时候才被通知。
?Controller（控制器）
控制器对于用户的输入做出反应。它创造和设置模型。
MVC 模型 2
Web 给软件开发人员带来了一些独特的挑战，最显著的就是客户端和服务器端的无结构连接。这种无结构连接行为使得模型很难知道视图的改变。在Web上，浏览器必须重复询问服务器端以此来发现应用程序结构的改变。
另外一个显而易见的改变就是相对于模型或者控制器，视图采用了不同的技术。当然，我们可以使用Java（或者PERL、C/C++ 或之前的其他代码）代码来生成HTML。这种方法存在一些弊端：
?Java 程序员应该开发服务，而不是HTML。
?布局的改变将需要改变代码。
?服务的客户将有能力去创造一些页面去满足他们的一些特殊需求。
?页面设计人员将不能直接介入到页面的开发中。
?嵌入在代码中的HTML将会变得丑陋。
对于Web，MVC的经典形式将需要改变。图4展示了MVC的Web适应，也就是通常所说的MVC模型2或者MVC 2。.
图 4. MVC 模型 2
Struts，MVC 2 的一种实现
Struts 是一组相互协作的类、servlet 和JSP 标记，它们组成一个可重用的MVC 2 设计。这个定义表示Struts 是一个框架，而不是一个库，但Struts 也包含了丰富的标记库和独立于该框架工作的实用程序类。图 5 显示了Struts 的一个概览。
图 5. Struts 概览
Struts 概览
?客户端浏览器
一个来自客户端浏览器的HTTP创建一个事件。Web 容器将会用一个HTTP 响应来作出响应。
?控制器
控制器接收来自浏览器的请求，并决定发送请求到何处。就Struts 而言，控制器就是一个以servlet执行的一个命令设计模式。struts-config.xml 文件配置控制器。
?业务逻辑
业务逻辑更新模型的状态，并帮助控制应用程序的流。就Struts 而言，这就是通过作为实际业务逻辑“瘦”包装的Action 类完成的。
?模型状态
模型代表了应用程序的状态。业务对象更新应用程序的状态。ActionForm
bean 在会话级或请求级表示模型的状态，而不是在持久级。JSP 文件使用
JSP 标记读取来自ActionForm bean 的信息。
?视图
视图就是一个JSP 文件。其中没有流程逻辑，没有业务逻辑，也没有模型
信息-- 只有标记。标记是使Struts 有别于其他框架（如Velocity）的因素之一。
Struts 详细资料
在图6中展示了一个无其他附属设备的阿帕奇struts的action包的UML图表。图6 显示了ActionServlet (Controller)、ActionForm (Form State) 和Action (Model Wrapper) 之间的最小关系。
图 6. 命令(ActionServlet) 与模型 (Action & ActionForm) 之间的关系的 UML 图
ActionServlet 类
你还记得使用函数映射的日子吗？你会映射一些输入时间到一个函数的一个
指针。如果你很老练，你可以把这些配置信息放进一个文件里并且在运行时加载该文件。函数指针装扮了在C语言结构化程序设计中的旧时光。
现在日子好过多了，自从我们有了Java技术、XML、J2EE等等之后。Struts 控制器是一个映射事件（事件通常是一个HTTP post）到类的一个servlet。猜猜怎么着-- 控制器用一个配置文件以致于你不必非硬编码这些值。生活变了，但方法依然如此。
ActionServlet 是MVC 实现的命令部分并且它是框架的核心。ActionServlet (Command) 创建并使用Action 、ActionForm 和ActionForward 。正如前面所提及的，struts-config.xml 文件配置Command。在Web 工程创建期间，Action 和ActionForm被扩展用来解决特殊的问题空间。文件struts-config.xml 指导ActionServlet 如何扩展这些类。这种方法有几个优点：
?网页设计人员不必费力地通过Java代码来理解应用程序的流程。
?当流程发生改变时Java开发人员不需要重新编译代码。
?通过扩展ActionServlet命令函数可以被添加进来。
ActionForm 类
ActionForm 维持着Web应用程序的会话状态。ActionForm 是一个必须为每个输入表单模型创建该类的子类的抽象类。当我说输入表单模型时,我就是说ActionForm 代表了一个由HTML 表单设置或更新的一般意义上的数据。例如，你可能有一个由HTML 表单设置的UserActionForm 。Struts 框架将会：
?检查UserActionForm 是否存在；如果不存在，它将会创建该类的一个实例。
?Struts 将使用HttpServletRequest 中相应的域设置
UserActionForm 的状态。没有太多糟糕的请求.getParameter() 调用。例如，Struts 框架将从请求流中提取fname 并调用UserActionForm.setFname() 。
?Struts 框架在将在传递它到业务包装UserAction 之前将更新UserActionForm的状态。
?在传递它到Action 类之前，Struts 将还会对UserActionForm 调用validation() 方法进行表单验证。备注：这样做通常并不明智。别的网页或业务对象可能有方法使用UserActionForm ，然而验证可能不同。在
UserAction 类中进行状态验证可能更好。
?UserActionForm能够维持一个会话级别。
备注：
?struts-config.xml 文件控制着HTML 表单请求与ActionForm 之间的映射。
?多重请求会被映射到UserActionForm 。
?UserActionForm 可被映射到诸如向导之类的多重页面的东西上。
Action 类
Action 类是一个围绕业务逻辑的一个包装器。Action 类的目的就是将HttpServletRequest 翻译给业务逻辑。要使用Action ，需重写process() 原理。
ActionServlet (命令)通过使用perform() 原理将参数化的类传递给ActionForm 。此外，没有太多讨厌的request.getParameter() 调用。通过事件到达这里的时间，输入表单数据（或HTML 表单数据）已经被从请求流中翻译出来并进入ActionForm 类中。
注：扩展Action 类时请注意简洁。Action 类应该控制应用程序的流程，而不应该控制应用程序的逻辑。通过将业务逻辑放在单独的包或EJB 中，我们就可以提供更大的灵活性和可重用性。
考虑Action 类的另一种方式是Adapter 设计模式。Action 的用途是“将类的接口转换为客户机所需的另一个接口。Adapter 使类能够协同工作，如果没有Adapter，则这些类会因为不兼容的接口而无法协同工作。”（摘自Gof 所著的Design Patterns - Elements of Reusable OO Software ）。本例中的客户机是ActionServlet ，它对我们的具体业务类接口一无所知。因此，Struts 提供了它能够理解的一个业务接口，即Action 。通过扩展Action ，我们使得我们的业务接口与Struts 业务接口保持兼容。（一个有趣的发现是，Action 是类而不是接口）。Action 开始为一个接口，后来却变成了一个类。真是金无足赤。）
Error 类
UML 图（图6）还包括ActionError 和ActionErrors 。ActionError 封装了单个错误消息。ActionErrors 是ActionError 类的容器，View 可以使用标记访问这些类。ActionError 是Struts 保持错误列表的方式。
图 7. Command (ActionServlet) 与 Model (Action) 之间的关系的 UML 图
ActionMapping 类
输入事件通常是在HTTP 请求表单中发生的，servlet 容器将HTTP 请求转换为HttpServletRequest 。控制器查看输入事件并将请求分派给某个Action 类。struts-config.xml 确定Controller 调用哪个Action 类。struts-config.xml 配置信息被转换为一组ActionMapping ，而后者又被放入ActionMappings 容器中。（你可能尚未注意到这一点，以s结尾的类就是容器）
ActionMapping 包含有关特定事件如何映射到特定Action 的信息。ActionServlet (Command) 通过perform() 方法将ActionMapping 传递给Action 类。这样就使Action 可访问用于控制流程的信息。
ActionMappings
ActionMappings 是ActionMapping 对象的一个集合。
Struts 的优点
?JSP 标记机制的使用
标记特性从JSP 文件获得可重用代码和抽象Java 代码。这个特性能很好地集成到基于JSP 的开发工具中，这些工具允许用标记编写代码。
?标记库
为什么要另发明一种轮子，或标记库呢？如果你在库中找不到你所要的标
记，那就自己定义吧。此外，如果你正在学习JSP 标记技术，则Struts 为你提供了一个起点。
?开放源码
你可以获得开放源码的全部优点，比如可以查看代码并让使用库的每个人检查代码。许多人都可以进行很好的代码检查。
?MVC 实现样例
如果你希望创建你自己的MVC 实现，则Struts 可增加你的见识。
?管理问题空间
分治是解决问题并使问题可管理的极好方法。当然，这是一把双刃剑。问题越来越复杂，并且需要越来越多的管理。
Struts 的缺点
?仍处于发展初期
Struts 开发仍处于初级阶段。他们正在向着发行版本1.0 而努力，但与任何1.0 版本一样，它不可能尽善尽美。
?仍在变化中
这个框架仍在快速变化。Struts 1.0 与Struts 0.5 相比变化极大。为了避免使用不赞成使用的方法，你可能隔一天就需要下载最新的Struts。在过去的 6 个月中，我目睹Struts 库从90K 增大到270K 以上。由于Struts 中的变化，我不得不数次修改我的示例，但我不保证我的示例能与你下载的Struts 协同工作。
?正确的抽象级别
Struts 是否提供了正确的抽象级别？对于网页设计人员而言，什么是正确的抽象级别呢？这是一个用$64K 的文字才能解释清楚的问题。在开发网页的过程中，我们是否应该让网页设计人员访问Java 代码？某些框架（如Velocity）说不应该，但它提供了另一种Web 开发语言让我们学习。在UI 开发中限制访问Java 有一定的合理性。最重要的是，如果让网页设计人员使用一点Java，他将使用大量的Java。在Microsoft ASP 的开发中，我总是看到这样的情况。在ASP 开发中，你应该创建COM 对象，然后编写少量
的ASP 脚本将这些COM 对象联系起来。但是，ASP 开发人员会疯狂地使用ASP 脚本。我会听到这样的话，“既然我可以用VBScript 直接编写COM 对象，为什么还要等COM 开发人员来创建它呢？”通过使用标记库，Struts 有助于限制JSP 文件中所需的Java 代码的数量。Logic Tag 就是这样的一种库，它对有条件地生成输出进行管理，但这并不能阻止UI 开发人员对
Java 代码的狂热。无论你决定使用哪种类型的框架，你都应该了解你要在其中部署和维护该框架的环境。当然，这项任务真是说起来容易做起来难。
?有限的适用范围
Struts 是一种基于Web 的MVC 解决方案，所以必须用HTML、JSP 文件和servlet 来实现它。
?J2EE 应用程序支持
Struts 需要支持JSP 1.1 和Servlet 2.2 规范的servlet 容器。仅凭这一点远不能解决你的全部安装问题，除非使用Tomcat 3.2。我用Netscape iPlanet 6.0 安装这个库时遇到一大堆问题，按理说它是第一种符合J2EE 的应用程序服务器。我建议你在遇到问题时访问Struts 用户邮件列表的归档资料。
?复杂性
在将问题分为几个部分的同时也引入了复杂性。毫无疑问，要理解Struts 必须接受一定的培训。随着变化的不断加入，这有时会令人很沮丧。欢迎访问本网站。
Struts 的前景
在软件开发的新时代事物都变化得很快。在最近5年里，我目睹过事物从
cgi/perl ，再到ISAPI/NSAPI、再到使用VB 的ASP、一直到现在的Java 和J2EE 的变迁。Sun 正在努力地适应JSP/servlet结构，就像他们通过Java语言和API在过去。你可以从Sun 的网站获得新的JSP 1.2 和Servlet 2.3 规范的草案。此外，一个标准的JSP 标记库正在出现。
附件2：外文原文（复印件）
出自《IBM System Journal,2006,44(2):33-37》作者：Malcolm Davis
Struts——An Open-source MVC Implementation
This article introduces Struts, a Model-View-Controller implementation that uses servlets and JavaServer Pages (JSP) technology. Struts can help you control change in your Web project and promote specialization. Even if you never implement a system with Struts, you may get some ideas for your future servlets and JSP page implementation
Introduction
Kids in grade school put HTML pages on the Internet. However, there is a monumental difference between a grade school page and a professionally developed Web site. The page designer (or HTML developer) must understand colors, the customer, product flow, page layout, browser compatibility, image creation, JavaScript, and more. Putting a great looking site together takes a lot of work, and most Java developers are more interested in creating a great looking object interface than a user interface. JavaServer Pages (JSP) technology provides the glue between the page designer and the Java developer.
If you have worked on a large-scale Web application, you understand the term change. Model-View-Controller (MVC) is a design pattern put together to help control change. MVC decouples interface from business logic and data. Struts is an MVC implementation that uses Servlets 2.2 and JSP 1.1 tags, from the J2EE specifications, as part of the implementation. You may never implement a system with Struts, but looking at Struts may give you some ideas on your future Servlets and JSP implementations.
Model-View-Controller (MVC)
JSP tags solved only part of our problem. We still have issues with validation, flow control, and updating the state of the application. This is where MVC comes to the rescue. MVC helps resolve some of the issues with the single module approach by dividing the problem into three categories:
?Model
The model contains the core of the application's functionality. The model encapsulates the
state of the application. Sometimes the only functionality it contains is state. It knows nothing about the view or controller.
?View
The view provides the presentation of the model. It is the look of the application. The view
can access the model getters, but it has no knowledge of the setters. In addition, it knows
nothing about the controller. The view should be notified when changes to the model occur.
?Controller
The controller reacts to the user input. It creates and sets the model.
MVC Model 2
?The Web brought some unique challenges to software developers, most notably the stateless connection between the client and the server. This stateless behavior made it difficult for the
model to notify the view of changes. On the Web, the browser has to re-query the server to
discover modification to the state of the application.
?Another noticeable change is that the view uses different technology for implementation than the model or controller. Of course, we could use Java (or PERL, C/C++ or what ever) code to generate HTML. There are several disadvantages to that approach:
?Java programmers should develop services, not HTML.
?Changes to layout would require changes to code.
?Customers of the service should be able to create pages to meet their specific needs.
?The page designer isn't able to have direct involvement in page development.
?HTML embedded into code is ugly.
?For the Web, the classical form of MVC needed to change. Figure 4 displays the Web adaptation of MVC, also commonly known as MVC Model 2 or MVC 2.
?
Struts details
?Displayed in Figure 6 is a stripped-down UML diagram of the org.apache.struts.action package. Figure 6 shows the minimal relationships among ActionServlet (Controller),
ActionForm (Form State), and Action (Model Wrapper).
Figure 6. UML diagram of the relationship of the Command (ActionServlet) to the Model (Action & ActionForm)
The ActionServlet class
Do you remember the days of function mappings? You would map some input event to a pointer to a function. If you where slick, you would place the configuration information into a file and load the file at run time. Function pointer arrays were the good old days of structured programming in C.
?Life is better now that we have Java technology, XML, J2EE, and all that. The Struts Controller is a servlet that maps events (an event generally being an HTTP post) to classes.
And guess what -- the Controller uses a configuration file so you don_t have to hard-code the values. Life changes, but stays the same.
?ActionServlet is the Command part of the MVC implementation and is the core of the Framework. ActionServlet (Command) creates and uses Action, an ActionForm, and
ActionForward. As mentioned earlier, the struts-config.xml file configures the Command.
During the creation of the Web project, Action and ActionForm are extended to solve the
specific problem space. The file struts-config.xml instructs ActionServlet on how to use the
extended classes. There are several advantages to this approach:
?The entire logical flow of the application is in a hierarchical text file. This makes it easier to view and understand, especially with large applications.
?The page designer does not have to wade through Java code to understand the flow of the application.
?The Java developer does not need to recompile code when making flow changes.
?Command functionality can be added by extending ActionServlet.
The ActionForm class
?ActionForm maintains the session state for the Web application. ActionForm is an abstract class that is sub-classed for each input form model. When I say input form model, I am
saying ActionForm represents a general concept of data that is set or updated by a HTML
form. For instance, you may have a UserActionForm that is set by an HTML Form. The
Struts framework will:
?Check to see if a UserActionForm exists; if not, it will create an instance of the class.
?Struts will set the state of the UserActionForm using corresponding fields from the HttpServletRequest. No more dreadful request.getParameter() calls. For instance, the Struts
framework will take fname from request stream and call UserActionForm.setFname().
?The Struts framework updates the state of the UserActionForm before passing it to the business wrapper UserAction.
?Before passing it to the Action class, Struts will also conduct form state validation by calling the validation() method on UserActionForm. Note: This is not always wise to do. There
might be ways of using UserActionForm in other pages or business objects, where the
validation might be different. Validation of the state might be better in the UserAction class.
?The UserActionForm can be maintained at a session level.
?Notes:
?The struts-config.xml file controls which HTML form request maps to which ActionForm.
?Multiple requests can be mapped UserActionForm.
?UserActionForm can be mapped over multiple pages for things such as wizards.
The Action class
The Action class is a wrapper around the business logic. The purpose of Action class is to translate the HttpServletRequest to the business logic. To use Action, subclass and overwrite the process() method.
The ActionServlet (Command) passes the parameterized classes to ActionForm using the perform() method. Again, no more dreadful request.getParameter() calls. By the time the event gets here, the input form data (or HTML form data) has already been translated out of the request stream and into an ActionForm class.
Figure 4. MVC Model 2
Struts, an MVC 2 implementation
Struts is a set of cooperating classes, servlets, and JSP tags that make up a reusable MVC 2 design. This definition implies that Struts is a framework, rather than a library, but Struts also contains an extensive tag library and utility classes that work independently of the framework. Figure 5 displays an overview of Struts.
Figure 5. Struts overview
Struts overview
?Client browser
An HTTP request from the client browser creates an event. The Web container will respond
with an HTTP response.
?Controller
The Controller receives the request from the browser, and makes the decision where to send
the request. With Struts, the Controller is a command design pattern implemented as a servlet.
The struts-config.xml file configures the Controller.
?Business logic
The business logic updates the state of the model and helps control the flow of the application.
With Struts this is done with an Action class as a thin wrapper to the actual business logic.
?Model state
The model represents the state of the application. The business objects update the application state. ActionForm bean represents the Model state at a session or request level, and not at a
persistent level. The JSP file reads information from the ActionForm bean using JSP tags.
?View
The view is simply a JSP file. There is no flow logic, no business logic, and no model
information -- just tags. Tags are one of the things that make Struts unique compared to other frameworks like Velocity.
Note: "Think thin" when extending the Action class. The Action class should control the flow and not the logic of the application. By placing the business logic in a separate package or EJB, we allow flexibility and reuse.
Another way of thinking about Action class is as the Adapter design pattern. The purpose of the Action is to "Convert the interface of a class into another interface the clients expect. Adapter lets classes work together that couldn_t otherwise because of incompatibility interface" (from Design Patterns - Elements of Reusable OO Software by Gof). The client in this instance is the ActionServlet that knows nothing about our specific business class interface. Therefore, Struts provides a business interface it does understand, Action. By extending the Action, we make our business interface compatible with Struts business interface. (An interesting observation is that Action is a class and not an interface. Action started as an interface and changed into a class over time. Nothing's perfect.)
The Error classes
The UML diagram (Figure 6) also included ActionError and ActionErrors. ActionError encapsulates an individual error message. ActionErrors is a container of ActionError classes that the View can access using tags. ActionErrors is Struts way of keeping up with a list of errors.
Figure 7. UML diagram of the relationship of the Command (ActionServlet) to the Model (Action)
The ActionMapping class
An incoming event is normally in the form of an HTTP request, which the servlet Container turns into
an HttpServletRequest. The Controller looks at the incoming event and dispatches the request to an Action class. The struts-config.xml determines what Action class the Controller calls. The
struts-config.xml configuration information is translated into a set of ActionMapping, which are put into container of ActionMappings. (If you have not noticed it, classes that end with s are containers) The ActionMapping contains the knowledge of how a specific event maps to specific Actions. The ActionServlet (Command) passes the ActionMapping to the Action class via the perform() method. This allows Action to access the information to control flow.
ActionMappings
ActionMappings is a collection of ActionMapping objects.
Struts pros
?Use of JSP tag mechanism
The tag feature promotes reusable code and abstracts Java code from the JSP file. This feature allows nice integration into JSP-based development tools that allow authoring with tags.
?Tag library
Why re-invent the wheel, or a tag library? If you cannot find something you need in the
library, contribute. In addition, Struts provides a starting point if you are learning JSP tag
technology.
?Open source
You have all the advantages of open source, such as being able to see the code and having
everyone else using the library reviewing the code. Many eyes make for great code review.
?Sample MVC implementation
Struts offers some insight if you want to create your own MVC implementation.
?Manage the problem space
Divide and conquer is a nice way of solving the problem and making the problem
manageable. Of course, the sword cuts both ways. The problem is more complex and needs
more management.
Struts cons
?Youth
Struts development is still in preliminary form. They are working toward releasing a version
1.0, but as with any 1.0 version, it does not provide all the bells and whistles.
?Change
The framework is undergoing a rapid amount of change. A great deal of change has occurred between Struts 0.5 and 1.0. You may want to download the most current Struts nightly
distributions, to avoid deprecated methods. In the last 6 months, I have seen the Struts library grow from 90K to over 270K. I had to modify my examples several times because of changes in Struts, and I am not going to guarantee my examples will work with the version of Struts
you download.
?Correct level of abstraction
Does Struts provide the correct level of abstraction? What is the proper level of abstraction
for the page designer? That is the $64K question. Should we allow a page designer access to Java code in page development? Some frameworks like Velocity say no, and provide yet
another language to learn for Web development. There is some validity to limiting Java code access in UI development. Most importantly, give a page designer a little bit of Java, and he
will use a lot of Java. I saw this happen all the time in Microsoft ASP development. In ASP
development, you were supposed to create COM objects and then write a little ASP script to
glue it all together. Instead, the ASP developers would go crazy with ASP script. I would hear "Why wait for a COM developer to create it when I can program it directly with VBScript?"
Struts helps limit the amount of Java code required in a JSP file via tag libraries. One such
library is the Logic Tag, which manages conditional generation of output, but this does not
prevent the UI developer from going nuts with Java code. Whatever type of framework you
decide to use, you should understand the environment in which you are deploying and
maintaining the framework. Of course, this task is easier said than done.
?Limited scope
Struts is a Web-based MVC solution that is meant be implemented with HTML, JSP files, and servlets.
?J2EE application support
Struts requires a servlet container that supports JSP 1.1 and Servlet 2.2 specifications. This
alone will not solve all your install issues, unless you are using Tomcat 3.2. I have had a great deal of problems installing the library with Netscape iPlanet 6.0, which is supposedly the first J2EE-compliant application server. I recommend visiting the Struts User Mailing List archive (see Resources) when you run into problems.
?Complexity
Separating the problem into parts introduces complexity. There is no question that some
education will have to go on to understand Struts. With the constant changes occurring, this
can be frustrating at times. Welcome to the Web.
?Where is...
I could point out other issues, for instance, where are the client side validations, adaptable
workflow, and dynamic strategy pattern for the controller? However, at this point, it is too
easy to be a critic, and some of the issues are insignificant, or are reasonable for a 1.0 release.
The way the Struts team goes at it, Struts might have these features by the time you read this article, or soon after.
Future of Struts
Things change rapidly in this new age of software development. In less than 5 years, I have seen things go from cgi/perl, to ISAPI/NSAPI, to ASP with VB, and now Java and J2EE. Sun is working hard to adapt changes to the JSP/servlet architecture, just as they have in the past with the Java language and API. You can obtain drafts of the new JSP 1.2 and Servlet 2.3 specifications from the Sun Web site. Additionally, a standard tag library for JSP files is appearing.
JSP Technology Conspectus And Specialties By:Kathy Sierra and Bert Bates Source: Servlet&JSP The JSP (Java Server mix) technology is used by the Sun microsystem issued by the company to develop dynamic Web application technology. With its easy, cross-platform, in many dynamic Web application programming languages, in a short span of a few years, has formed a complete set of standards, and widely used in electronic commerce, etc. In China, the JSP now also got more extensive attention, get a good development, more and more dynamic website to JSP technology. The related technologies of JSP are briefly introduced. The JSP a simple technology can quickly and with the method of generating Web pages. Use the JSP technology Web page can be easily display dynamic content. The JSP technology are designed to make the construction based on Web applications easier and efficient, and these applications and various Web server, application server, the browser and development tools work together. The JSP technology isn't the only dynamic web technology, also not the first one, in the JSP technology existed before the emergence of several excellent dynamic web technology, such as CGI, ASP, etc. With the introduction of these technologies under dynamic web technology, the development and the JSP. Technical JSP the development background and development history In web brief history, from a world wide web that most of the network information static on stock transactions evolution to acquisition of an operation and infrastructure. In a variety of applications, may be used for based on Web client, look no restrictions. Based on the browser client applications than traditional based on client/server applications has several advantages. These benefits include almost no limit client access and extremely simplified application deployment and management (to update an application, management personnel only need to change the program on a server, not thousands of installation in client applications). So, the software industry is rapidly to build on the client browser multi-layer application. The rapid growth of exquisite based Web application requirements development of technical improvements. Static HTML to show relatively static content is right choice, The new challenge is to create the interaction based on Web applications, in these procedures, the
JSP技术概述 一、JSP的好处 二、JSP页面最终会转换成servler。因而，从根本上，JSP页面能够执 行的任何任务都可以用servler来完成。然而，这种底层的等同性并不意味着servler和JSP页面对于所有的情况都等同适用。问题不在于技术的能力，而是二者在便利性、生产率和可维护性上的不同。毕竟，在特定平台上能够用Java编程语言完成的事情，同样可以用汇编语言来完成，但是选择哪种语言依旧十分重要。 和单独使用servler相比，JSP提供下述好处： 三、λJSP中HTML的编写与维护更为简单。JSP中可以使用常规的HTML： 没有额外的反斜杠，没有额外的双引号，也没有暗含的Java语法。 四、λ能够使用标准的网站开发工具。即使对那些对JSP一无所知的 HTML工具，我们也可以使用，因为它们会忽略JSP标签（JSP tags）。 五、λ可以对开发团队进行划分。Java程序员可以致力于动态代码。Web 开发人员可以将经理集中在表示层（presentation layer）上。对于大型的项目，这种划分极为重要。依据开发团队的大小，及项目的复杂程度，可以对静态HTML和动态内容进行弱分离（weaker separation）和强分离（stronger separation）。 六、在此，这个讨论并不是让您停止使用servlets，只使用JSP。几乎 所有的项目都会同时用到这两种技术。针对项目中的某些请求，您可能会在MVC构架下组合使用这两项技术。我们总是希望用适当的工具完成相对应的工作，仅仅是servlet并不能填满您的工具箱。 二、JSP相对于竞争技术的优势 许多年前，Marty受到邀请,参加一个有关软件技术的小型(20个人)研讨会.做在Marty旁边的人是James Gosling--- Java编程语言的发明者。 隔几个位置,是来自华盛顿一家大型软件公司的高级经理。在讨论过程中,研讨会的主席提出了Jini的议题,这在当时是一项新的Java技术.主席向该经理询问他的想法.他继续说,他们会持续关注这项技术,如果这
毕业设计(论文) 外文文献翻译 专业 学生姓名 班级 学号 指导教师 XX 学院
外文资料名称：An Overview of Servlet and JSP Technology 外文资料出处：Internet 附件： 1.外文资料翻译译文 2.外文原文 指导教师评语： 签名： 年月日
Servlet和JSP技术简述 Nagle and Wiegley XX译 摘要：Servlet程序在服务器端运行，动态地生成Web页面与传统的CGI和许多其他类似CGI的技术相比，Java Servlet具有更高的效率，更容易使用，功能更强大，具有更好的可移植性，更节省投资。 关键字：JSP技术，Servlet，HTTP服务 1.1Servlet的功能 Servlets是运行在Web或应用服务器上的Java程序，它是一个中间层，负责连接来自Web浏览器或其他HTTP客户程序的请求和HTTP服务器上的数据库或应用程序。Servlet的工作是执行西门的任务，如图1.1所示。 图1.1Web中间件的作用 （1）读取客户发送的显式数据。 最终用户一般在页面的HTML表单中输入这些数据。然而，数据还有可能来自applet或定制的HTTP客户程序。 （2）读取由浏览器发送的隐式请求数据。 图1.1中显示了一条从客户端到Web服务器的单箭头，但实际上从客户端传送到Web服务器的数据有两种，它们分别为用户在表单中输入的显式数据，以及后台的HTTP信息。两种数据都很重要。HTTP信息包括cookie、浏览器所能识别的媒体类型和压缩模式等。 （3）生成结果。 这个过程可能需要访问数据库、执行RMI或EJB调用、调用Web服务，或者直接计算得出对应的响应。实际的数据可能存储在关系型数据库中。该数据库可能不理解HTTP，或者不能返回HTML形式的结果，所有Web浏览器不能直接与数据库进行会话。即使它能够做到这一点，为了安全上的考虑，我们也不希望让它这么做。对应大多数
外文原文 JSP JSP (JavaServer Pages) is initiated by Sun Microsystems, Inc., with many companies to participate in the establishment of a dynamic web page technical standards. JSP technology somewhat similar to ASP technology, it is in the traditional HTML web page document (*. htm, *. html) to insert the Java programming paragraph (Scriptlet) and JSP tag (tag), thus JSP documents (*. jsp). Using JSP development of the Web application is cross-platform that can run on Linux, is also available for other operating systems. JSP technology to use the Java programming language prepared by the category of XML tags and scriptlets, to produce dynamic pages package processing logic. Page also visit by tags and scriptlets exist in the services side of the resources of logic. JSP page logic and web page design and display separation, support reusable component-based design, Web-based application development is rapid and easy. Web server in the face of visits JSP page request, the first implementation of the procedures of, and then together with the results of the implementation of JSP documents in HTML code with the return to the customer. Insert the Java programming operation of the database can be re-oriented websites, in order to achieve the establishment of dynamic pages needed to function. JSP and Java Servlet, is in the implementation of the server, usually returned to the client is an HTML text, as long as the client browser will be able to visit. JSP 1.0 specification of the final version is launched in September 1999, December has introduced 1.1 specifications. At present relatively new is JSP1.2 norms, JSP2.0 norms of the draft has also been introduced. JSP pages from HTML code and Java code embedded in one of the components. The server was in the pages of client requests after the Java code and then will generate the HTML pages to return to the client browser. Java Servlet JSP is the technical foundation and large-scale Web application development needs of Java Servlet and JSP support to complete. JSP with the Java technology easy to use, fully object-oriented, and a platform-independent and secure, mainly for all the characteristics of the Internet. JavaScript, which is completely distinct from the Java programming language, is normally used to dynamically generate HTML on the client, building parts of the Web
Struts——一种开源MVC的实现 这篇文章介绍Struts，一个使用servlet和JavaServer Pages技术的一种Model-View-Controller的实现。Struts可以帮助你控制Web项目中的变化并提高专业化。即使你可能永远不会用Struts实现一个系统，你可以获得一些想法用于你未来的servlet和JSP网页的实现中。 简介 在小学校园里的小孩子们都可以在因特网上发布HTML网页。然而，有一个重大的不同在一个小学生和一个专业人士开发的网站之间。网页设计师（或者HTML开发人员）必须理解颜色、用户、生产流程、网页布局、浏览器兼容性、图像创建、JavaScript等等。设计漂亮的网站需要做大量的工作，大多数Java开发人员更注重创建优美的对象接口，而不是用户界面。JavaServer Pages(JSP)技术为网页设计人员和Java开发人员提供了一种联系钮带。 如果你开发过大型Web应用程序，你就理解“变化”这个词语。“模型-视图-控制器”(MVC)就是用来帮助你控制变化的一种设计模式。MVC减弱了业务逻辑接口和数据接口之间的耦合。Struts是一种MVC实现，它将Servlet2.2和JSP 1.1标记（属于J2EE规范）用作实现的一部分。你可能永远不会用Struts实现一个系统，但了解一下Struts或许使你能将其中的一些思想用于你以后的Servlet和JSP实现中。 模型-视图-控制器(MVC) JSP标签只解决了我们问题中的一部分。我们依然有验证、流控制、以及更新应用程序结构的问题。这就是MVC从哪儿来以及来干嘛的。MVC通过把问题分成三类来帮助解决一些与单模块相关的问题： ?Model（模型） 模块包括应用程序功能的核心。模型封装着应用程序的各个结构。有时它所包含的唯一功能就是结构。它对于视图或者控制器一无所知。 ?View（视图） 视图提供了模型的演示。它是应用程序的外表。视图可以进入模型获得者，
中文4816字 外文资料翻译 （2011 届大学本科）题目： 学院： 专业： 班级： 姓名： 学号： 主指导教师： 2011年02 月24 日 教务处印制
外文原文 JSP application frameworks brian wright、michael freedman https://www.doczj.com/doc/6b10424484.html,/pdf/introduction-to-machine-learning/ What are application frameworks: A framework is a reusable, semi-complete application that can be specialized to produce custom applications [Johnson]. Like people, software applications are more alike than they are different. They run on the same computers, expect input from the same devices, output to the same displays, and save data to the same hard disks. Developers working on conventional desktop applications are accustomed to toolkits and development environments that leverage the sameness between applications. Application frameworks build on this common ground to provide developers with a reusable structure that can serve as the foundation for their own products. A framework provides developers with a set of backbone components that have the following characteristics: 1.They are known to work well in other applications. 2. They are ready to use with the next project. 3. They can also be used by other teams in the organization. Frameworks are the classic build-versus-buy proposition. If you build it, you will understand it when you are done—but how long will it be before you can roll your own? If you buy it, you will have to climb the learning curve—and how long is that going to take? There is no right answer here, but most observers would agree that frameworks such as Struts provide a significant return on investment compared to starting from scratch, especially for larger projects. Other types of frameworks: The idea of a framework applies not only to applications but to application componentsas well. Throughout this article, we introduce other types of frameworks that you can use with Struts. These include the Lucene search engine, the Scaffold toolkit, the Struts validator, and the Tiles tag library. Like application frameworks, these tools provide semi-complete versions of a subsystem that can be specialized to
THE TECHNIQUE DEVELOPMENT HISTORY OF JSP By:Kathy Sierra and Bert Bates Source:Servlet&JSP The 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 GENERALIZE The 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.
(文档含英文原文和中文翻译) 中英文对照外文翻译 JSP技术 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)。与SSJS和ASP相比，JSP具有更好的可扩展性，并且它不专属于任何一家厂商或某一特定的Web服务器。尽管JSP规范是由Sun公司制定的，但任何厂商都可以在自己的系统上实现JSP。 在Sun正式发布JSP(Java Server Pages)之后，这种新的Web应用开发技术很快引起了人们的关注。JSP为创建高度动态的Web应用提供了一个独特的开发环境。按照Sun的说法，JSP能够适应市场上包括Apache WebServer、IIS4.0在内的85%的服务器产品。 本文将介绍JSP相关的知识，以及JavaBean的相关内容，当然都是比较粗略的介绍其中的基本内容，仅仅起到抛砖引玉的作用，如果读者需要更详细的信息，请参考相应的JSP的书籍。 1.1 概述 JSP(Java Server Pages)是由Sun Microsystems公司倡导、许多公司参与一起建立的一种动态网页技术标准，其在动态网页的建设中有其强大而特别的功能。JSP与Microsoft的ASP技术非常相似。两者都提供在HTML代码中混合某种程序代码、由语言引擎解释执行程序代码的能力。下面我们简单的对它进行介绍。 JSP页面最终会转换成servlet。因而，从根本上，JSP页面能够执行的任何任务都可以用servlet来完成。然而，这种底层的等同性并不意味着servlet和JSP 页面对于所有的情况都等同适用。问题不在于技术的能力，而是二者在便利性、生产率和可维护性上的不同。毕竟，在特定平台上能够用Java编程语言完成的事情，同样可以用汇编语言来完成，但是选择哪种语言依旧十分重要。 和单独使用servlet相比，JSP提供下述好处： JSP中HTML的编写与维护更为简单。JSP中可以使用常规的HTML：没有额外的反斜杠，没有额外的双引号，也没有暗含的Java语法。 能够使用标准的网站开发工具。即使是那些对JSP一无所知的HTML工具，我们也可以使用，因为它们会忽略JSP标签（JSP tags）。 可以对开发团队进行划分。Java程序员可以致力于动态代码。Web开发人员可以将精力集中在表示层（presentation layer）上。对于大型的项目，这种划分极为重要。依据开发团队的大小，及项目的复杂程度，可以对静态HTML和动态内容
翻译资料原文 Overview of JSP Technology Benefits of JSP 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. Advantages of JSP Over Competing Technologies 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
JSP简介 JSP(JavaServer Pages)是由Sun Microsystems公司倡导、许多公司参与一起建立的一种动态网页技术标准。JSP技术有点类似ASP技术，它是在传统的网页HTML文件(*.htm,*.html)中插入Java程序段(Scriptlet)和JSP标记(tag)，从而形成JSP文件(*.jsp)。 用JSP开发的Web应用是跨平台的，即能在Linux下运行，也能在其他操作系统上运行。 JSP技术使用Java编程语言编写类XML的tags和scriptlets，来封装产生动态网页的处理逻辑。网页还能通过tags和scriptlets访问存在于服务端的资源的应用逻辑。JSP将网页逻辑与网页设计和显示分离，支持可重用的基于组件的设计，使基于Web的应用程序的开发变得迅速和容易。 Web服务器在遇到访问JSP网页的请求时，首先执行其中的程序段，然后将执行结果连同JSP文件中的HTML代码一起返回给客户。插入的Java程序段可以操作数据库、重新定向网页等，以实现建立动态网页所需要的功能。 JSP与Java Servlet一样，是在服务器端执行的，通常返回该客户端的就是一个HTML文本，因此客户端只要有浏览器就能浏览。 JSP的1.0规范的最后版本是1999年9月推出的，12月又推出了1.1规范。目前较新的是JSP1.2规范，JSP2.0规范的征求意见稿也已出台。 JSP页面由HTML代码和嵌入其中的Java代码所组成。服务器在页面被客户端请求以后对这些Java代码进行处理，然后将生成的HTML页面返回给客户端的浏览器。Java Servlet 是JSP的技术基础，而且大型的Web应用程序的开发需要Java Servlet和JSP配合才能完成。JSP具备了Java技术的简单易用，完全的面向对象，具有平台无关性且安全可靠，主要面向因特网的所有特点。 JSP技术的强势 （1）一次编写，到处运行。在这一点上Java比PHP更出色，除了系统之外，代码不用做任何更改。 （2）系统的多平台支持。基本上可以在所有平台上的任意环境中开发，在任意环境中进行系统部署，在任意环境中扩展。相比ASP/PHP的局限性是显而易见的。
附件1：外文资料翻译译文 Struts——一种开源MVC的实现 这篇文章介绍Struts，一个使用servlet 和JavaServer Pages 技术的一种Model-View-Controller 的实现。Struts 可以帮助你控制Web 项目中的变化并提高专业化。即使你可能永远不会用Struts实现一个系统，你可以获得一些想法用于你未来的servlet 和JSP 网页的实现中。 简介 在小学校园里的小孩子们都可以在因特网上发布HTML 网页。然而，有一个重大的不同在一个小学生和一个专业人士开发的网站之间。网页设计师（或者HTML开发人员）必须理解颜色、用户、生产流程、网页布局、浏览器兼容性、图像创建、JavaScript 等等。设计漂亮的网站需要做大量的工作，大多数Java 开发人员更注重创建优美的对象接口，而不是用户界面。JavaServer Pages (JSP) 技术为网页设计人员和Java 开发人员提供了一种联系钮带。 如果你开发过大型Web 应用程序，你就理解“变化”这个词语。“模型-视图-控制器”(MVC) 就是用来帮助你控制变化的一种设计模式。MVC 减弱了业务逻辑接口和数据接口之间的耦合。Struts 是一种MVC 实现，它将Servlet 2.2 和JSP 1.1 标记（属于J2EE 规范）用作实现的一部分。你可能永远不会用Struts 实现一个系统，但了解一下Struts 或许使你能将其中的一些思想用于你以后的Servlet和JSP 实现中。 模型-视图-控制器 (MVC) JSP标签只解决了我们问题中的一部分。我们依然有验证、流控制、以及更新应用程序结构的问题。这就是MVC从哪儿来以及来干嘛的。MVC通过把问题分成三类来帮助解决一些与单模块相关的问题：
JSP Open Category: WEB, JAVA, dynamic pages, the Knowledge Network Contents ? JSP Profile ? JSP technology strength ? JSP technology vulnerable ? JSP six built-in objects: ? JSP dynamic web site development and technology JSP Profile JSP (JavaServer Pages) is initiated by Sun Microsystems, Inc., with many companies to participate in the establishment of a dynamic web page technical standards. JSP technology somewhat similar to ASP technology, it is in the traditional HTML web page document (*. htm, *. html) to insert the Java programming paragraph (Scriptlet) and JSP tag (tag), thus JSP documents (*. jsp). Using JSP development of the Web application is cross-platform that can run on Linux, is also available for other operating systems. JSP technology to use the Java programming language prepared by the category of XML tags and scriptlets, to produce dynamic pages package processing logic. Page also visit by tags and scriptlets exist in the services side of the resources of logic. JSP page logic and web page design and display separation, support reusable component-based design, Web-based application development is rapid and easy. Web server in the face of visits JSP page request, the first implementation of the procedures of, and then together with the results of the implementation of JSP documents in HTML code with the return to the customer. Insert the Java programming operation of the database can be re-oriented websites, in order to achieve the establishment of dynamic pages needed to function. JSP and Java Servlet, is in the implementation of the server, usually returned to the client is an HTML text, as long as the client browser will be able to visit.