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Java Coding Standards
Version 1.1
Table of Contents
1Introduction 4
1.1Purpose 4
1.2Scope 4
1.3References 4
2General Concepts 5
2.1Why are coding standards important? 5
2.2What Makes a Good Name? 5
2.3Good Documentation 7
2.4Internationalization 7
3Java Source Files 9
3.1Package Naming 9
3.2Import Statements 9
3.3Comments 9
3.4Class Guidelines and Naming Conventions 10
3.5Method Guidelines and Naming Conventions 11
3.5.1The 60 Second Rule 11
3.5.2Naming Guidelines 11
3.5.3Visibility 11
3.6Field (Variable) Guidelines 11
3.7Code formatting 12
3.7.1Indentation 12
3.7.2White Space 12
3.7.3Line Length 12
3.7.4Wrapping Lines 13
3.7.5Control Structure Formatting 13
4Programming Practices 16
4.1Access to Instance and Class Variables 16
4.2Referring to Static Class Variables and Methods 16
4.3Local Variables 16
4.3.1Naming Local Variables 16
4.4Variable Assignments 18
4.5Multi-function Operators 18
4.6Ternary Operator 18
4.7Order of Operations / Parentheses 18 5Code Example 20
Java Coding Standards
1 Introduction
This document is to detail the Java coding standards specific to #### Software Inc. This document is a
modification of the coding standards from Sun Microsystems Inc. Most of the material herein is taken from the ―Java Code Conventions‖ document published by Sun Microsystems and available at
https://www.doczj.com/doc/8a6357686.html,/docs/codeconv/. Where appropriate, modifications have been made and additional
material has been added to cover the entire scope of coding at #### Software Inc.
1.1 Purpose
This document is intended to assist developers in the area of code development, such that all code
developed by #### Software will look similar. Code developed according to a standard is proven to
increase readability, make code easier to maintain and greatly reduce maintenance costs.
1.2 Scope
The scope of this coding standard is for the #### Project initially. However, it is desirable that any
development in Java by #### Software Inc. would follow these standards.
1.3 References
1.―Code Conventions for the Java Programming Language‖, April 20, 1999, version
2.1, Sun Microsystems
Inc. (https://www.doczj.com/doc/8a6357686.html,/docs/codeconv/)
2 General Concepts
2.1 Why are coding standards important?
Coding standards for Java are important because they lead to greater consistency within your code and the code of your teammates. Greater consistency leads to code that is easier to understand, which in turn means it is easier to develop and to maintain. This reduces the overall cost of the applications that you create.
You have to remember that your Java code will exist for a long time, long after you have moved on to other projects. An important goal during development is to ensure that you can transition your work to another
developer, or to another team of developers, so that they can continue to maintain and enhance your work without having to invest an unreasonable effort to understand your code. Code that is difficult to understand runs the risk of being scrapped and rewritten – nobody would be proud of the fact that their code needed to be rewritten. If everyone is doing their own thing then it makes it very difficult to share code between
developers, raising the cost of development and maintenance.
No standard is perfect and no standard is applicable to all situations; sometimes you find yourself in a
situation where one or more standards do not apply. This leads the prime directive of standards:
When you go against a standard, document it.All standards, except for this one, can be
broken. If you do so, you must document why you broke the standard, the potential implications of
breaking the standard, and any conditions that may/must occur before the standard can be applied
to this situation.
The bottom line is that you need to understand each standard, understand when to apply them, and just as importantly when not to apply them.
2.2 What Makes a Good Name?
We will be discussing naming conventions throughout the standards, so let’s set the stage with a few basics:
https://www.doczj.com/doc/8a6357686.html,e full English descriptors that accurately describe the variable/field/class/…For example, use
names like firstName, grandTotal, or CorporateCustomer. Although names like x1, y1, or fn
are easy to type because they’re short, they do not provide any indication of what they represent and
result in code that is difficult to understand, maintain, and enhance.
https://www.doczj.com/doc/8a6357686.html,e terminology applicable to the domain.If your users refer to their clients as customers, then use
the term Customer for the class, not Client. Many developers will make the mistake of creating
generic terms for concepts when perfectly good terms already exist in the industry/domain.
https://www.doczj.com/doc/8a6357686.html,e mixed case to make names readable.You should use lower case letters in general, but capitalize
the first letter of class names and interface names, as well as the first letter of any non-initial word.
Non-constant names should not contain underscores. Constant values (static final types) should
be all uppercase with underscores separating parts of the name. This makes it easy to recognize
constants where they are used in the source code. Note that this rule applies only to types which are
both static and final; it does not apply to simply static types (whose values can be altered
during execution).
Examples: public class MyClass {
private int simpleVariable;
private static final int SOME_VALUE = 0;
…
}
https://www.doczj.com/doc/8a6357686.html,e abbreviations sparingly, but if you do so then use them intelligently.This means you should
choose them wisely, and you should use them consistently. For example, if you want to use a short form for the word ―number,‖ then choose one of nbr, or num, and use only that one.
5.Avoid long names (< 15 characters is a good idea).Although the class name
PhysicalOrVirtualProductOrService might seem to be a good class name at the time this name is simply too long and you should consider renaming it to something shorter, perhaps something like Offering. Like all the standards, there are times you might choose to violate this one. For example, class names are often created by code generation tools. When extending or created related classes it might make sense to use similar long names.
6.Avoid names that are similar or differ only in case.For example, the variable names
persistentObject and persistentObjects should not be used together, nor should
anSqlDatabase and anSQLDatabase (singular and plural forms of the same name). This is the motivation for using the ―List‖ postfix on collections – it avoids the singular/plural forms of the name from getting confused (see the next item).
https://www.doczj.com/doc/8a6357686.html,e “List” postfix for collections and collection classes. A collection which contains objects of
some type should have the postfix ―List‖ on the name. For example, a class which is a collection of Customer objects would be CustomerList. Likewise, a reference to a CustomerList object might be named overdueCustomerList. Using the list postfix clearly distinguishes the collection from a singular instance of an item in the collection. For example, it avoids having the object references goodCustomer and goodCustomers in the same code section – this leads to code which has to be very carefully read to be understood correctly.
8.Avoid leading or trailing underscores. Avoid underscores altogether except in static final types (see
#3 above).
9.Avoid type-based (“Hungarian”) Notation. This technique prefixes names with an abbreviated type
code (such as ―i‖ for integer, ―f‖ for float, ―str‖ for String, etc.). Although once very popular in the C/C++ environment, it has proven to be ineffective for a number of reasons:
a)It simply makes source code more difficult to read. In extreme cases code becomes almost
illegible due to the excessive prefixing required. Hard to read code is hard to enhance and
maintain.
b)When such names appear in interfaces (public class properties or via accessor methods) they fix
the interface to a specific data type. If the interface is changed you are faced with either leaving
the name the same and have the prefix not match the type, or changing the name and changing all code that references it. A classic example of this problem exists in the Windows 95 operating
system. The type of a message parameter was changed from an unsigned short to an unsigned
long between Windows 3.1 and Windows 95. To maintain source compatibility the parameter
na me is still ―usParam‖ but in fact the parameter is an unsigned long (―ul‖) , not an unsigned
short (―us‖). Now the interface is inconsistent because the notation no longer matches the
implementation.
c)With the complex objects of Java (and other OO languages), the prefix notation is not adequate to
express the datatype anyway, except at the most primitive level. Since objects may be cast up or
down the inheritance tree, or cast to an interface which is implemented by the object, no single
prefix can properly describe the object type.
2.3 Good Documentation
We will also be discussing documentation conventions, so let’s discuss some of the basics first:
https://www.doczj.com/doc/8a6357686.html,ments should add to the clarity of your code.The reason why you document your code is to
make it more understandable to you, your coworkers, and to any other developer who comes after you.
2.If your program isn’t worth documenting, it probably isn’t worth running.What else needs to be
said? This hits the nail on the head.
3.Avoid decoration, i.e. do not use banner-like comments.In the 1960s and 1970s programmers got
into the habit of drawing boxes, typically with asterisks, around their internal comments. It adds little
value to the end product. You want to write clean readable code, not draw pretty boxes. Using
separator comment lines (a single line of dashes or asterisks) to offset an important comment block can
be useful, but do not take time to create or maintain a full box around the comments.
4.Keep comments simple.Some of the best comments are simple, point-form notes. You do not have to
write a book, you just have to provide enough information so that others can understand your code.
5.Write the documentation before, or as, you write the code.The best way to document code is to
write the comments before you write the code. This gives you an opportunity to think about how the
code will work before you write it and will ensure that the documentation gets written.
Alternatively, you should at least document your code as you write it. Because documentation makes
your code easier to understand you are able to take advantage of this fact while you are developing it.
This of it this way: if you are going to invest the time writing documentation you should at least get
something out of it. If you write a l ong section of code and think ―I’ll come back later and put in
comments‖ –don’t. Write the comments as you go; it will help you understand and think about the
code you are writing.
Comments written later are usually superficial and lack the insight that existed at the time the code was
written. Write them while the ideas behind the logic are fresh in your mind.
Also, be very careful when cut & paste is used in writing documentation comments. Most inaccuracies
occur when comments are pasted, but the writer fails to make the necessary changes to the comments.
6.Document why something is being done, not just what.Fundamentally, a programmer can always
look at a piece of code and figure out what it does. For example, anyone can see from the code below
that a 5% discount is being given on orders of $1,000 dollars or more. Why is this being done? Is there
a business rule that says that large orders get a discount? Is there a limited-time special on large orders
or is it a permanent program? Was the original programmer just being generous? You don’t know
unless it is documented somewhere, either in the source code itself or in an external document.
if ( grandTotal >= 1000.00){
grandTotal = grandTotal * 0.95;
}
2.4 Internationalization
Java has some built in support for internationalization via objects called Resource Bundles. The key to
making any product support internationalization is by not hard-coding strings. Any text that the user may
see or have access to should not be hard-coded, and instead, be routed through a resource bundle. (More will come later here as we gain better understanding on how we plan to use resource bundles).
3 Java Source Files
Java source files contain the following information: package statements, import statements, class
declarations, variables and methods. Optionally, they may contain comments and inner classes.
3.1 Package Naming
In Java, package names must be unique throughout all Java code loaded into a virtual machine. JBuilder
will not allow two packages of the same name to loaded into the editor. However, once a package is
exported to JAR file the project concept does not exist; so if two packages had the same name in different projects, they could not be exported to the same JAR, or even be loaded into the same JVM.
Packages are used in Java to prevent class name collisions between classes created by different developers.
It is designed to allow Java code created anywhere in the world, by any company, to be loaded safely into a JVM and combined with any other Java code without concern about duplicate class names. In the JVM at runtime, all class names are fully qualified with the package name. So if there are two classes with the
same name, but in different packages, the JVM will always be able to identify the correct one.
In order to prevent package name conflicts with Java code written by developers all over the world, it was necessary to use a world-wide naming system that would guarantee uniqueness of package names. Since there is already such a name system in place (the internet domain name system), Sun decided to use that
naming system in package names. The Sun standard specifies that Java package names begin with the
company domain name in reverse order. Package qualifiers beyond the reversed domain name may be
arbitrarily defined by the owner of that domain.
For example, Java packages written by IBM begin with ―com.ibm‖, and are followed by a package naming system developed by IBM to keep their internal Java developers from creating conflicting names within the ―com.ibm‖ space. (Roughly, the convention is ―com.ibm.
In keeping with the Sun standard, all Java package names created by #### Software should begin with the qualifiers ―com.####‖. Subsequent qualifiers should identify t he product or common library name,
followed by any qualifiers desired by the product developers. For example:
com.####.
This identifies a package of Java classes developed by #### Software. It is part of the ―i2k‖ product and ―component‖ common library, and specifically, the DOE component.
3.2 Import Statements
Import statements typically immediately follow the package declaration. Although java enables developers to import entire packages, it is recommended that developers import only the specific classes that are
needed. Exceptions to this are some of the most common packages associated with the JDK, such as
java.util, https://www.doczj.com/doc/8a6357686.html,ng, java.awt, and javax.swing.
An import statement looks like this:
import java.util.*;
import com.####.i2k.pse.SomeClass;
3.3 Comments
Java has several types of comments: Documentation, C-style, single-line, End end-line. These four are
described below.
It is recommended that all source files begin with a c-style comment that lists the class name, change
information, and copyright notice:
/*
* Classname
*
* Change Information
*
* Copyright Notice
*/
Documentation comments are what the javadoc tool recognizes and is able to turn into html documentation.
Any public or protected class, variable, or method should have documentation style comments associated
with it. If we do a good job here, producing our API documentation will be easy! For more information on how to write Javadoc comments, visit http://intranet.####.com:5000/~hodgin/javadoc/howto.html (See
Java Source File Example at the end of this document for an example).
When you comment out code, document when and why the code was commented out so you or other
developers will know why it was commented out.
3.4 Class Guidelines and Naming Conventions
A Class should represent a single entity. There is no recommended guideline on how long a class should be,
however, if a class begins to get very large, it should be closely examined to determine if it should be
broken into multiple classes.
Each class should have coded explicit constructors. If no explicit constructor for a class, exists, a default
(no Param) constructor is ―created‖ for the class. The constructor will have the same visibility as the class
itself. Although this behavior is acceptable at times, there are cases where this could cause problems. It
may lead to other classes being able to instantiate the class that the developer did not intend, or may allow unintentional avoidance of a singleton paradigm. Whatever the case, it is just good programming practice to explicitly define the constructor(s) of a class.
Class names should be nouns, in mixed case, with the first letter of each internal word capitalized. Keep the class names descriptive, yet simple.
Inner classes are classes which are defined inside another class. Their purpose should be to serve its
containing class only and should be private (There may be cases where the inner class should be more
visible). In general, if the inner class serves a class outside the containing class, then it should be broken
out to be a normal class. Inner classes should be defined after the containing class’ declaration and class
variables and just before the constructor(s) of the containing class (See ―5 Code Examples‖ for an example).
3.5 Method Guidelines and Naming Conventions
Methods are where the primary functionality of a class may be found. Methods encapsulate a single unit of work in a class. For this reason, they should remain short and to the point. A good rule to use when writing methods that can be easily read and understood using the ―60 Second Rule.‖
3.5.1 The 60 Second Rule
Another programmer should be able to look at your method and be able to fully understand what it does,
why it does it, and how it does it in less than 60 seconds. If they cannot, then your code is too difficult to
maintain and should be improved. S ixty seconds, that’s it. A good rule of thumb is that if a member
function is more than one screen of source code then it is probably too long. Note that good comments,
formatting, and variable naming all contribute to quick understanding of a member function.
3.5.2 Naming Guidelines
The guidelines provided in section 2.2 What Makes a Good Name apply to methods. Beyond those
guidelines, methods should be verbs describing the action or function they are to perform. Accessor
methods, methods which provide outside access to class variables, should begin with get or set (see section
4.1 Access to Instance and Class Variables for more detail on this topic). Getter functions which return a
boolean value should be prefixed with is (Examples: isVisible(), isEmpty()).
3.5.3 Visibility
The visibility of a class’s member functions should be as restrictive as possible. Much like the principle of data hiding prevents external classes from having data dependencies on the internal class variables, member visibility controls the potential for functional dependencies. It is desirable to reduce the functional
dependency so that how a class performs its functions may be altered without side effects in other classes.
By making methods of class A invisible to external classes, call it B, (i.e. private or protected if subclasses need to inherit it) the external class, B, cannot have dependencies on the internal operation of class A.
less more
visible Private Protected Default Public visible
(Friendly)
3.6 Field (Variable) Guidelines
Fields may be freely named within the general naming guidelines described in What Makes a Good Name
in section 2.2.
For example:
firstName
zipCode
customerList
orderList
Avoid overly long, and overly short field names. Names which are very long (greater than 15-18 characters) make it difficult to format expressions in which the field name is used. Statements which use long field
names tend to run off the right side of the source code window or have to be wrapped onto several physical lines of code. In either case the result is less readable source code.
Also avoid names which are abbreviated for no particular reason other than to save a few keystrokes. For
example, using ―off‖ instead of ―offset‖, ―len‖ instead of ―length‖, etc. Note that this rule may not
apply to variables, which if they are of a limited scope, may be shortened. See in What Makes a Good
Name in section 2.2.
Again, it is recommended that fields which are collections be post-fixed with ―List‖.
It is also recommended that fields be declared private or protected, and that all outside access to the class
variables be done through accessor methods.
3.7 Code formatting
3.7.1 Indentation
Indentation is used to visually express the nesting (―block‖) level of code. It allows the reader to
quickly determine the code structure without examining explicit syntax details, such as where the
curly braces match up. Indentation should always be done with TAB characters rather than
spaces. JBuilder allows the user to set the n umber of spaces that a ―tab‖ represents. The
recommended value is 4. Using the tab key to indent rather that spaces insures that users will see
code indented to their liking all the time. For example, if user A sets his tabbing to 2 spaces and
user B sets his to 4 spaces, as long as they both use the tab key to indent, each will see the others
code indented to their own preference. However, if user A uses the space bar to indent, when user
B loads in A’s code, B will see the code indented with only 2 spaces, whereas he prefers four. This
value can be set in JBuilder by clicking ―Tools‖ ―Editor Options‖ from the menu bar. On the
dialog that appears, set the ―Tab Indent‖ property to the number of spaces you wish your tab
indention to be. Again, the recommended value is 4.
3.7.2 White Space
A few blank lines, called whitespace, added to your Java code can help to make it much more
readable by breaking it up into small, easy-to-digest sections. Use a single blank line to separate
logical groups of code such as control structures, groups of assignment statements, and groups of
variable declarations.
Use 2 blank lines between methods, and between class variable declarations and the methods.
3.7.3 Line Length
Avoid lines longer than 80 characters, since they’re not hand led well by many terminals and
tools.
Note: Examples for use in documentation should have a shorter line length—generally no
more than 70 characters.
3.7.4 Wrapping Lines
When an expression will not fit on a single line, break it according to these general principles: ?Break after a comma.
?Break before an operator.
?Prefer higher-level breaks to lower-level breaks.
?Align the new line with the beginning of the expression at the same level on the previous line.
?If the above rules lead to confusing code or to code t hat’s squished up against the right margin, just indent 8 spaces instead.
Here are some examples of breaking method calls:
someMethod(longExpression1, longExpression2, longExpression3,
longExpression4, longExpression5);
var = someMethod1(longExpression1,
someMethod2(longExpression2,
longExpression3));
Following are two examples of breaking an arithmetic expression. The first is preferred, since the break occurs outside the parenthesized expression, which is at a higher level.
longName1 = longName2 * (longName3 + longName4 - longName5)
+ 4 * longname6; // PREFER
longName1 = longName2 * (longName3 + longName4
- longName5) + 4 * longname6; // AVOID
Following are two examples of indenting method declarations. The first is the conventional
case. The second would shift the second and third lines to the far right if it used conventional indentation, so instead it indents only 8 spaces.
//CONVENTIONAL INDENTATION
someMethod(int anArg, Object anotherArg, String yetAnotherArg,
Object andStillAnother) {
...
}
//INDENT 8 SPACES TO AVOID VERY DEEP INDENTS
private static synchronized horkingLongMethodName(int anArg,
Object anotherArg, String yetAnotherArg,
Object andStillAnother) {
...
}
Line wrapping for if statements should be done like this:
if ((condition1 && condition2)
|| (condition3 && condition4)
||! (condition5 && condition6)) {
doSomethingAboutIt();
}
3.7.5 Control Structure Formatting
if, if-else, if else-if else Statements
The if-else class of statements should have the following form:
if (condition) {
statements;
}
if (condition) {
statements;
} else {
statements;
}
if (condition) {
statements;
} else if (condition) {
statements;
} else {
statements;
}
Note:if statements always use braces {}. Avoid the following error-prone form:
if (condition) //AVOID! THIS OMITS THE BRACES {}!
statement;
for Statements
A for statement should have the following form:
for (initialization; condition; update) {
statements;
}
while Statements
A while statement should have the following form:
while (condition) {
statements;
}
do-while Statements
A do-while statement should have the following form:
do {
statements;
} while (condition);
switch Statements
A switch statement should have the following form:.
switch (condition) {
case ABC:
statements;
/* falls through */
case DEF:
statements;
break;
case XYZ:
statements;
break;
default:
statements;
break;
}
Every time a case falls through (doesn’t include a break statement), add a comment where the
break statement would normally be. This is shown in the preceding code example with the /* falls through */ comment.
Every switch statement should include a default case. The break in the default case is redundant, but it prevents a fall-through error if later another case is added.
try-catch Statements
A try-catch statement should have the following form:
try {
statements;
} catch (ExceptionClass e) {
statements;
}
A try-catch statement may also be followed by finall y,
which executes regardless of whether or not the try block has completed successfully.
try {
statements;
} catch (ExceptionClass e) {
statements;
} finally {
statements;
}
4 Programming Practices
4.1 Access to Instance and Class Variables
Don’t make any instance or class variable public without good reason. Often, instance variables don’t need to be explicitly set or gotten—often that happens as a side effect of method calls.
All access to instance variables from outside the class should be through getter and setter methods. The
format for these methods is to prefix the variable name with get or set. For example:
public class Foo {
private int someValue = 0;
...
public int getSomeValue() {
return someValue;
}
public void setSomeValue(int newValue) {
someValue = newValue;
}
}
One example of appropriate public instance variables is the case where the class is essentially a data
structure, with no behavior. In other words, if you would have used a struct instead of a class (if Java supported struct), then it’s appropriate to make the class’s instance variables public.
4.2 Referring to Static Class Variables and Methods
Avoid using an object to access a class (static) variable or method. Use a class name instead. For example: classMethod(); //OK
AClass.classMethod(); //OK
anObject.classMethod(); //AVOID!
4.3 Local Variables
A local variable is an object or data item that is defined within the scope of a block, often a member
function or an if/then/else code block. (The scope of a variable is the area of code in which the variable can be directly used; each variable’s scope is defined by where the variable is declared and the qualifiers such as public and private). The scope of a local variable (a variable defined in a method, as opposed to a class variable defined in the class header) is the block in which it is defined. The important coding
standards for local variables focus on:
?Naming conventions
?Documentation conventions
?Declarations
4.3.1 Naming Local Variables
Use full English descriptors with the first letter of any non-initial word in uppercase. For the sake
of convenience, however, this naming convention is relaxed for several specific types of local
variables:
?Loop counters
?Exceptions
?Limited Scope Variables
4.3.1.1 Loop Counters
Because loop counters are a very common use for local variables, and because it was acceptable in C/C++, the use of i, j, or k, is acceptable for loop counters. If you use these names for loop
counters, use them consistently. A common alternative is to use names like loopCounter or
simply counter, but the problem with this approach is that you often find names like counter1
and counter2in member functions that require more than one counter. The bottom line is that i, j, k work as counters, they’re quick to type in, and they’re generally accepted.
4.3.1.2 Exception Objects
Because exception handling is also very common in Java coding, the use of the letter ―e” for a
generic exception is considered acceptable. Where multiple nested exceptions are caught,
secondary exception objects can be named e2, e3, etc.
4.3.1.3 Limited Scope Variables
When a variable is declared and used in a very limited scope (e.g. within a scope of maybe 5 or 10 source lines), it is acceptable to shorten the variable name. Since the variable declaration is
visually close to all its usage, there is little loss in clarity by use of a short name. In the following
example, the Client object ―c‖ is in effect a temporary variable used to iterate a list of Client
obj ects. The variable ―c‖ exists only within the scope of the loop which is only a few source code lines long.
For example:
Enumeration list = sharedCosting.getClientList();
int memberCount = 0;
while (list.hasMoreElements()) {
Client c = (Client)list.nextElement();
if (c.isMember()) {
memberCount++;
}
}
The declaration of Client ―c‖ could also be moved outside the loop, so long as the scope
of usage of the variable remains very small:
Enumeration list = sharedCosting.getClientList();
int memberCount = 0;
Client c;
while (list.hasMoreElements()) {
c = (Client)list.nextElement();
if (c.isMember()) {
memberCount++;
}
}
Note there is a risk here that the variable ―c‖ will be used later in this same method, and
thus would not be of limited scope (and should be better named). It is safer to put such
declarations inside the body of the loop where possible.
4.4 Variable Assignments
Avoid assigning several variables to the same value in a single statement. It is hard to read. Example: fooBar.fChar = barFoo.lchar = 'c'; // AVOID!
Do not use the assignment operator in a place where it can be easily confused with the equality operator.
Example:
if (c++ = d++) { // AVOID! (Java disallows)
...
}
should be written as
if ((c++ = d++) != 0) {
...
}
Do not use embedded assignments in an attempt to improve run-time performance. This is the job of the
compiler. Example:
d = (a = b + c) + r; // AVOID!
should be written as
a =
b + c;
d = a + r;
4.5 Multi-function Operators
The use of increment and decrement operators in a larger expression is strongly discouraged. For example:
a = (c / b++) * (d / b);
It is not clear without a detailed understanding of Java semantics, if the variable b is incremented before or after it is used in the division with c, and what is it’s value when it is used in the division with d? These
―order of precedence‖ type issues are best avoided by using such operators only in standalone statements:
b++;
a = (c / b) * (d / b);
In this example, there is no ambi guity with regard to the value of ―b‖ in the calculation of ―a‖. This also follows the ―only do one thing in one line of code‖ guideline.
4.6 Ternary Operator
The if/else statement has a shorthand notation called the ternary operator (?). Avoid the use of this
operator. The ternary operator shortens an if statement as follows:
if (x) {
a = b;
} else { a = x ? b : c;
a = c;
}
Anyone with programming experience can understand the if/else on the left. Only experienced java or
c/c++ programmers will understand the ternary expression on the right.
4.7 Order of Operations / Parentheses
It is generally a good idea to use parentheses liberally in expressions involving mixed operators to avoid operator precedence problems. Even if the operator precedence seems clear to you, it might not be to others—you shouldn’t
assume that other programmers know precedence as well as you do.
if (a == b && c == d) // AVOID!
if ((a == b) && (c == d)) // USE
Write your code so that you are not dependent on the default order of operations.
5 Code Example
The following example shows how to format a Java source file containing a single public class. Interfaces are formatted similarly.
/*
* @(#)Blah.java 1.82 99/03/18
*
* Copyright (c) 1994-1999 Sun Microsystems, Inc.
* 901 San Antonio Road, Palo Alto, California, 94303, U.S.A.
* All Rights Reserved.
*
* This software is the confidential and proprietary information of Sun
* Microsystems, Inc. ("Confidential Information"). You shall not
* disclose such Confidential Information and shall use it only in
* accordance with the terms of the license agreement you entered into
* with Sun.
*/
package java.blah;
import java.blah.blahdy.BlahBlah;
/**
* Class description goes here.
*
* @version 1.82 18 Mar 1999
* @author Firstname Lastname
*/
public class Blah extends SomeClass {
/* A class implementation comment can go here. */
/** classVar1 documentation comment */
public static int classVar1;
/**
* classVar2 documentation comment that happens to be
* more than one line long
*/
private static Object classVar2;
/** instanceVar1 documentation comment */
public Object instanceVar1;
/** instanceVar2 documentation comment */
protected int instanceVar2;
/** instanceVar3 documentation comment */
private Object[] instanceVar3;
/* Inner class comments go here */
private class MyInnerClass {
// the inner class definition
// goes here
}
/**
* ... constructor Blah documentation comment...
*/
public Blah() {
// ...implementation goes here...
}
/**
* ... method doSomething documentation comment...
本科毕业论文（设计） 题目:基于Java的人事管理系统设计与实现系别: 信息工程学院 班级: 2011级计算机科学与技术(软件技术方向) 起讫日期: 2012年10月16日-2013年5月31日
基于Java的人事管理系统设计与实现 三明学院信息工程学院 2011级计算机科学与技术（软件方向） 摘要：随着计算机的逐步发展、复杂度逐渐变强，人工作业已经无法适应现代的管理，随之取代的是计算机科学而开发的人事管理系统，而且一个良好的人事管理系统势在必行。人事管理系统是对工作人员进行统一的管理，可以方便的进行录入、查询、删除、修改等操作。其开发主要包括后台数据库的建立和维护以及前端应用程序的开发两个方面。对于前者要求建立起数据一致和完整性强、数据安全性好的数据库。而对于后者则要求应用程序功能完备，易使用等特点。按照系统的基本功能，系统的开发可以归结为软件开发技术和数据库应用技术。目前主要的软件编程语言有Java、C#、C++等，本系统主要采用Java语言为开发技术。在数据库的选择上，为了用户友好的查询和强大的搜索能力，采用Microsoft公司的Access 作为数据库平台。设计流程从系统的需求分析开始，确定系统的流程与模块的划分，再到数 据库设计，最后开始每个模块的编程。 关键词：人事管理系统；java语言；Access 第一章绪论 (5)
1.1信息化的发展 (5) 1.2课题的研究背景 (5) 1.3课题的研究目的 (6) 1.4系统开发关键技术与开发环境 (6) 1.4．1 JAVA语言简介 (6) 1.4．2 JAVA的优势与特点 (7) 1.5 MyEcpse的特点与开发环境 (7) 1.6运行环境和开发工具 (8) 第二章需求分析 (8) 2.1系统需求分析 (8) 2.2功能分析 (9) 2.3可行性分析 (9) 2.3.1经济可行性 (9) 2.3.2技术可行性 (9) 2.3.3操作可行性 (10) 第三章系统设计 (10) 3.1结构设计 (10) 3.2功能结构图 (10) 3.3功能流程及工作流描述 (11) 第四章数据库设计 (13) 4.1数据库表设计 (13) 4.2数据库E-R图设计 (14) 第五章详细设计 (15) 5.1系统登录界面 (15) 5.2人事管理系统主界面模块 (16) 5.3基础信息管理模块 (16) 5.3.1添加人员信息模块 (17) 5.3.2修改人员信息模块 (18) 5.3.3删除人员信息模块 (18) 5.3.4查询人员信息模块 (19) 5.3.5部门管理模块 (19) 5.4人员调动管理模块 (20) 5.4.1人员调动模块 (20) 5.4.2调动历史查询模块 (21) 5.5人员考核管理模块 (21) 5.5.1调动历史查询模块 (22) 5.5.2调动历史查询模块 (22) 5.6劳资管理模块 (23) 5.6.1劳资分配管理模块 (24) 5.6.2劳资历史查询模块 (24) 第六章系统调试 (25) 6.1程序调试 (25) 6.2程序的测试 (25) 6.2.1测试的重要性和目的 (25)
Java程序课程设计 任务书 钟表的设计与开发 1、主要内容： 创建一个钟表。 借助swing类和接口内部类的实现，在本程序中以实现Runnable接口内部类的形式创建多线程对象。 Runnable接口只定义了一个run（）方法，所以调用start和sleep()方法时，必须创建Thread实例化对象。Interrupt（）方法的作用是中断线程。 其作用方式是：多线程对象.interrupt（）。 2、具体要求（包括技术要求等）： 系统的功能要求： 1.可以记录时间的钟表。 2.熟悉JAVA中swing的组件运用，基本工具的熟练掌握。 学习并掌握以下技术：Java等。 熟练使用以下开发工具：JCreator + JDK 1.6.0_02 等实现系统上述的功能。 3、进度安排： 12月28日~ 12月29日：课程设计选题，查找参考资料 12月29日~ 1月2日：完成程序代码的编写 1月2日~ 1月3日：系统测试与完善 1月4日~ 1月5日：完成课程设计报告，准备答辩 4、主要参考文献 [1]张帆.Java范例开发大全[M].北京:清华大学出版社,2010:0-831. [2]耿祥义,张跃平.Java大学实用教程[M].北京电子工业出版社,2008:213-216
摘要 随着经济全球化的发展，推动生活节奏的加快，也给时间赋予了更重要的意义。基于方便人们更好的掌握时间，我们小组设计出了这个小时钟。 本时钟是一个基于Java语言设计而成的一个小程序，目的是显示时间，并且能调准时钟。整个程序从符合操作简便、界面友好、灵活使用的要求出发，完成调用、调整的全过程。 本课程设计报告介绍了时钟的构成，论述了目标功能模块；给出了时钟设计的步骤，程序主要所用到的Swing组件以及graphics方法。 关键词：时钟，
工厂系列模式的优缺点： 1.让用户的代码和某个特定类的子类的代码解耦 用户不必知道它所使用的对象是怎样创建的，只需知道该对象有哪些方法 2.抽象工厂模式可以为用户创建一系列相关的对象，使用户和创建这些对象的类脱耦 MVC模式是不是一种设计模式？为什么 MVC不是设计模式，应该是框架/架构模式，因为它的定义是抽象的，没有足够的细节描述使你直接去实现，而只能根据MVC的概念和思想，用几个设计模式组合实现。 举出一个生活中使用装饰者模式的例子，用程序实现思路 举个生活中的例子，俗话说“人在衣着马在鞍”，把这就话用装饰者模式的语境翻译一下，“人通过漂亮的衣服装饰后，男人变帅了，女人变漂亮了；”。对应上面的类图，这里人对应于ConcreteComponent,而漂亮衣服则对应于ConcreteDecorator； 设计模式如何分类，每一个类别都有什么特征？ 设计模式分为3类，分别是：创建型模式、行为型模式、结构型模式。 创建型特点：避免用户直接使用new运算符创建对象。 行为型特点：怎样合理的设计对象之间的交互通信，以及怎样合理的为对象分配职 结构型特点：主要用于处理类或对象的组合 Java jdk中使用了哪些设计模式 1.单例 2.静态工厂 3.工厂方法 4.抽象工厂 5.构造者 6.原型 7.适配器8桥接9.组合10.装饰器11.外观12.享元 页脚内容1
14.代理15.迭代器16.观察者17.协调者18.模板方法19.策略20.责任链21.命令22.空对象25.解释器 面向对象的设计原则有哪些？ 开闭原则、面向抽象的原则（依赖倒转原则）、多用组合少用继承原则、高内聚-低耦合原则。 观察者模式的推拉有什么不同？使用场景 推，具体主题将变化后的数据全部交给具体观察者。场景：当具体主题认为具体观察者需要这些变换后的数据时，往往采用推数据方式； 拉，具体主题不将变化后的数据交给具体观察者，而是提供获得这些数据的方法。场景：当具体主题不知道具体观察者是否需要这些变换后的数据时，往往采用拉数据的方式。 策略模式和工厂模式有什么不同？ 策略模式定义了一系列算法，将他们一个个封装，并且他们之间可以相互替换； 工厂模式定义一个创建对象的接口，让子类决定实例化哪一个类 5观察者模式的推拉有什么不同？适用场景 现在要说的分歧在这里： “推”的方式是指，Subject维护一份观察者的列表，每当有更新发生，Subject会把更新消息主动推送到各个Observer去。 “拉”的方式是指，各个Observer维护各自所关心的Subject列表，自行决定在合适的时间去Subject获取相应的更新数据。 “推”的好处包括： 页脚内容2
基于JavaWeb人事管理系统的设计与实现
毕业设计（论文）原创性声明和使用授权说明 原创性声明 本人郑重承诺：所呈交的毕业设计（论文），是我个人在指导教师的指导下进行的研究工作及取得的成果。尽我所知，除文中特别加以标注和致谢的地方外，不包含其他人或组织已经发表或公布过的研究成果，也不包含我为获得及其它教育机构的学位或学历而使用过的材料。对本研究提供过帮助和做出过贡献的个人或集体，均已在文中作了明确的说明并表示了谢意。 作者签名：日期： 指导教师签名：日期： 使用授权说明 本人完全了解大学关于收集、保存、使用毕业设计（论文）的规定，即：按照学校要求提交毕业设计（论文）的印刷本和电子版本；学校有权保存毕业设计（论文）的印刷本和电子版，并提供目录检索与阅览服务；学校可以采用影印、缩印、数字化或其它复制手段保存论文；在不以赢利为目的前提下，学校可以公布论文的部分或全部内容。 作者签名：日期：
学位论文原创性声明 本人郑重声明：所呈交的论文是本人在导师的指导下独立进行研究所取得的研究成果。除了文中特别加以标注引用的内容外，本论文不包含任何其他个人或集体已经发表或撰写的成果作品。对本文的研究做出重要贡献的个人和集体，均已在文中以明确方式标明。本人完全意识到本声明的法律后果由本人承担。 作者签名：日期：年月日 学位论文版权使用授权书 本学位论文作者完全了解学校有关保留、使用学位论文的规定，同意学校保留并向国家有关部门或机构送交论文的复印件和电子版，允许论文被查阅和借阅。本人授权大学可以将本学位论文的全部或部分内容编入有关数据库进行检索，可以采用影印、缩印或扫描等复制手段保存和汇编本学位论文。 涉密论文按学校规定处理。 作者签名：日期：年月日 导师签名：日期：年月日
项目效果图： 源代码： import java.awt.Color; import java.awt.Font; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.geom.Ellipse2D; import java.awt.geom.Line2D; import java.awt.image.BufferedImage; import java.awt.EventQueue; import java.util.Calendar; import java.util.GregorianCalendar; import javax.swing.JFrame; import javax.swing.JPanel; /* author: 蒋冰 */ public class MoveDraw extends JFrame{ private Draw draw = new Draw(); public static void main(String[] args){ EventQueue.invokeLater(new Runnable() { public void run() { try { MoveDraw frame = new MoveDraw(); frame.setVisible(true);
} catch (Exception e) { e.printStackTrace(); } } }); } public MoveDraw(){ super(); setTitle("动画"); setBounds(400,300,400,300); add(draw); Thread thread = new Thread(draw);// 创建线程对象 thread.start();// 启动线程对象 } class Draw extends JPanel implements Runnable{ Calendar calendar = new GregorianCalendar(); int hour = calendar.get(Calendar.HOUR); int minute = calendar.get(Calendar.MINUTE); int second = calendar.get(Calendar.SECOND); int year = calendar.get(Calendar.YEAR); int mouth = calendar.get(Calendar.MONTH); int day = calendar.get(Calendar.DAY_OF_MONTH); int week = calendar.get(Calendar.DAY_OF_WEEK); String date = year+"-"+mouth+"-"+day; String weeks[] = new String[]{"星期天","星期一","星期二","星期三","星期四","星期五","星期六"}; double theta = second * (2 * Math.PI)/60 ; double theta1 = (minute * (2 * Math.PI) + theta)/60; double theta2 = (hour*(2 * Math.PI) + theta1)/12; public void paint(Graphics g){ Graphics2D g2 = (Graphics2D) g; g2.clearRect(0, 0, 400, 300); g2.translate(draw.getWidth()/2, draw.getHeight()/2); g2.setColor(Color.blue); Font font = new Font("楷体",Font.ROMAN_BASELINE ,14); g2.setFont(font); g2.drawString(date, -25, 30); g2.drawString(weeks[week-1]+"", -15, 50); g2.setColor(Color.black); for(int i=1; i<=12; i++){ double theta = i*2*Math.PI/12;
Java设计模式之工厂模式(Factory) 时间：2009-08-04 17:23 来源：未知作者：和水柔石 CSDN IE QQ百度我挖Google POCO Yahoo新浪365Key天极和讯博拉Live奇客鲜果收客饭否叽歪挖客 核心提示：作者：和水柔石一、引子话说十年前，有一个爆发户，他家有三辆汽车（Benz （奔驰）、Bmw （宝马）、Audi （奥迪）看来这人比较爱国，没有日本车），还雇了司机为他开车。不过，爆发户坐车时总是这样：上Benz 车后跟司机说开奔驰车！，坐上Bmw 后他说开 作者：和水柔石 一、引子 话说十年前，有一个爆发户，他家有三辆汽车（Benz （奔驰）、Bmw （宝马）、Audi （奥迪）看来这人比较爱国，没有日本车），还雇了司机为他开车。不过，爆发户坐车时总是这样：上Benz 车后跟司机说" 开奔驰车！" ，坐上Bmw 后他说" 开宝马车！" ，坐上Audi 后他说" 开奥迪车！" 。你一定说：这人有病！直接说开车不就行了？！而当把这个爆发户的行为放到我们程序语言中来，我们发现C 语言一直是通过这种方式来坐车的！幸运的是，这种有病的现象在OO 语言中可以避免了。下面以Java 语言为基础来引入我们本文的主题：工厂模式！！ 二、简介 工厂模式主要是为创建对象提供了接口。工厂模式按照《Java 与模式》中的提法分为三类： 1. 简单工厂模式(Simple Factory) 2. 工厂方法模式(Factory Method) 3. 抽象工厂模式(Abstract Factory) 这三种模式从上到下逐步抽象，并且更具一般性。还有一种分类法，就是将简单工厂模式看为工厂方法模式的一种特例，两个归为一类。下面是使用工厂模式的两种情况： 1. 在编码时不能预见需要创建哪种类的实例。 2. 系统不应依赖于产品类实例如何被创建、组合和表达的细节 三、简单工厂模式 顾名思义，这个模式本身很简单，而且使用在业务较简单的情况下。 它由三种角色组成（关系见下面的类图）： 1、工厂类角色：这是本模式的核心，含有一定的商业逻辑和判断逻辑。在java 中它往往由一个具体类实现。 2、抽象产品角色：它一般是具体产品继承的父类或者实现的接口。在java 中由接口或者抽象类来实现。 3、具体产品角色：工厂类所创建的对象就是此角色的实例。在java 中由一个具体类实现。
学校代码：11517 学号：201011002240 HENAN INSTITUTE OF ENGINEERING 文献综述 题目基于Java 的人事管理系统 的设计与实现 学生姓名许耀辉 专业班级信息与计算科学1042班 学号201011002240 系（部）理学院 指导教师(职称)董西广(讲师) 完成时间2014年3月4日
基于Java的人事管理系统的设计与实现 摘要：随着计算机的发展，科技的发展，现阶段的人事管理系统越来越不能满足企业的需要，特别是对于一些企业仍然采用人工管理的方式，这种方式不仅增加了企业的成本，而且极其容易出错，设计一种基于Java的人事管理系统就应运而生了，人事管理系统基本实现了企业人事管理的基本应用，包括人事信息管理的增、删、改、查，考勤信息管理的增、删、改、查，个人简历信息管理等基本应用，设计的人事管理涉及MySQL数据库的操作，Eclipse以及jdbc数据库的连接等相关知识。 关键词：Java/MySQL/Eclipse/人事管理 1 引言 21世纪最激烈的竞争当属人才的竞争，一个具有多学科知识的复合性人才或许是一个企业发展壮大所不可或缺的重要因素。因此人力资源已逐步成为企业最重要的资源，人力资源管理（Human Resource Management，HRM）也成为现代企业管理工作中的重要内容之一。随着社会的发展，科技的进步，计算机的应用在社会各领域中都得到了普及，越来越多的人都感受到利用计算机进行各类管理的科学和便捷；认识到管理信息系统对于管理工作的重要性[1]。 本次论文创作的主要目的是设计一款简单、易操作的现代人事管理系统，在论文创作的过程中，我借助学校和个人收集的相关资料，利用图书馆和网络等渠道，广泛查阅相关资料，分析前人成果的基础上，明确系统设计思路。 2 人事管理系统的发展 2.1人事管理系统的国外的发展 人事管理系统的发展经过三个阶段的发展。 人事管理系统的发展历史可以追溯到20世纪60年代末期。由于当时计算机技术已经进入实用阶段，同时大型企业用手工来计算和发放薪资既费时费力又容
单片机课程设计报告设计题目：简易电子时钟的设计 院别： 专业班级： 学号：
姓名： 指导教师: 摘要 通过一学期单片机的学习，对其已经有了初步的了解，但是随着社会的不断发展，单片机的应用正在不断地走向深入，它特别适合于与控制有关的系统，越来越广泛地应用于自动控制，智能化仪器，仪表，数据采集，军工产品以及家用电器等各个领域，单片机往往是作为一个核心部件来使用，在根据具体硬件结构，以及针对具体应用对象特点的软件结合，以作完善。我们也借此课程设计的机会，对单片机有更深一步的了解与学习。 本次课程课程设计的目的是设计一个简易的电子时钟，通过一个8位共阴极数码管进行时、分、秒的显示，另外设置7个按键，一个用来调整小时，一个用来调整分钟，一个开关控制是否调整时间。 关键词：AT89C51,数码管，按键，DS1303时钟芯片
1.概述 本设计是锻炼我们的自学能力合作能力，依靠团队的力量去完成一项具体的任务系统的训练了所学知识，设计的过程必将是难忘的，这也将是大学向社会工作过度的一个重要阶段。 本阶段过后要去能够熟练的运用单片机中的计数器、定时器、中断、数码管显示等参考教材或者相关资料，采用C语言实现数字时钟功能，在数码管上实时显示，并运用Protues软件绘制电路原理图，并进行仿真验证和误差分析。 2.系统总体方案设计 2.1系统方案的确定 用6位数码管，可以显示出时、分、秒；用P2端口控制位选，由定时器进行时间的控制（秒）；当总按键按下时可以进行时间调整； 2.2方案分析 2.3系统总框图 图2.1
3.系统硬件系统设计 3.1复位电路 单片机复位电路就好比电脑的重启部分，当电脑在使用中出现死机，按下重启按钮电脑内部的程序从头开始执行。单片机也一样，当单片机系统在运行中，受到环境干扰出现程跑飞的时候，按下复位按钮内部的程序自动从头开始执行。 复位电路的工作原理： 在单片机系统中，系统上电启动的时候复位一次，当按键按下的时候系统再次复位，如果释放后再按下，系统还会复位。所以可以通过按键的断开和闭合在运行的系统中控制其复位。单片机复位电路如下图 图3.1 3.2时钟电路 单片机运行需要时钟支持——就像计算机的CPU一样，如果没有时钟电路来产生时钟驱动单片机，那单片机就不能执行程序。 单片机可以看成是在时钟驱动下的时序逻辑电路。 以5l单片机为例随明：51单片机为l2个时钟周期执行一条指令。也就是说单片机运行一条指令，必须要用r2个时钟周期。没有这个时钟，单片机就跑不起来了，也没有办法定时和进行和时间有关的操作。 时钟电路是微型计算机的心脏，它控制着计算机的二个节奏。CPU就是通过复杂的时序电路完成不同的指令功能的。51的时钟信号可以由两种方式产生：一种是内部方式，利用芯片内部的振荡电路，产生时钟信号：另一种为外部方式，时钟信号由外部引入。
抽象工厂模式是所有形态的工厂模式中最为抽象和最具一般性的一种形态。抽象工厂模式是指当有多个抽象角色时，使用的一种工厂模式。抽象工厂模式可以向客户端提供一个接口，使客户端在不必指定产品的具体的情况下，创建多个产品族中的产品对象。根据LSP原则，任何接受父类型的地方，都应当能够接受子类型。因此，实际上系统所需要的，仅仅是类型与这些抽象产品角色相同的一些实例，而不是这些抽象产品的实例。换言之，也就是这些抽象产品的具体子类的实例。工厂类负责创建抽象产品的具体子类的实例。 当每个抽象产品都有多于一个的具体子类的时候，工厂角色怎么知道实例化哪一个子类呢？比如每个抽象产品角色都有两个具体产品。抽象工厂模式提供两个具体工厂角色，分别对应于这两个具体产品角色，每一个具体工厂角色只负责某一个产品角色的实例化。每一个具体工厂类只负责创建抽象产品的某一个具体子类的实例。 每一个模式都是针对一定问题的解决方案，工厂方法模式针对的是一个产品等级结构；而抽象工厂模式针对的是多个产品等级结果。 下面是一个java抽象工厂的实现实例. 我们以交通工具(Vihicle),食品(Foot),武器(Weapon)为抽象产品类为例: 交通工具(Vihicle) public abstract class Vihicle { public abstract void run(); } 食品(Foot) public abstract class Foot { public abstract void printName(); } 武器(Weapon) public abstract class Weapon { public abstract void shoot(); } 这三种抽象产品类都有两种子类的实现: 交通工具(Vihicle)有实现类Car,Broom public class Car extends Vihicle{ public void run(){ System.out.println("冒着烟奔跑中的Car..."); } } public class Broom extends Vihicle{ public void run(){ System.out.println("一路沙尘暴飞奔而来.."); } } 食品(Foot)有实现类Mushroom,Apple
武汉工程大学邮电信息与工程学院 Java课程综合设计报告 目录 摘要...................................................................................................II Abstract................................................................................................ II 第一章概述.............................................................. .................... (1) 1.1 前言 (1) 1.2 系统功能简介 (2) 第二章设计简介及设计方案论述 (3) 2.1 设计简介....................................................................................... . .3 2.2 设计方案论述 (3) 第三章详细设计 (4) 3.1 算法描述 (4) 3.2 系统功能模块 (7) 第四章设计结果及分析 (8) 4.1 系统实现....................................................................................... . .8 4.2 结果分析 (8) 总结 (9) 致谢 (10) 参考文献 (11) 附录主要程序代码 (12) - I -
JAVA课程项目报告 项目题目：利用JAVA实现一个小时钟的程序 专业班级：10软件工程 利用JAVA实现一个时钟的小程序 1.软件开发的需求分析 在当今的信息时代，时钟已经成为人们生活中必不可少
的应用工具，Java语言是当今流行的网络编程语言，它具有面向对象、与平台无关、安全、多线程等特点。使用Java 语言不仅可以实现大型企业级的分布式应用系统，还能够为小型的、嵌入式设备进行应用程序的开发。面向对象的开发方法是当今世界最流行的开发方法，它不仅具有更贴近自然的语义，而且有利于软件的维护和继承。为了进一步巩固课堂上所学到的知识，深刻把握Java语言的重要概念及其面向对象的特性，锻炼我们熟练的应用面向对象的思想和设计方法解决实际问题的能力，开设了Java程序设计课程设计。 此次课程设计的题目为简单的小时钟程序设计，通过做巩固所学Java语言基本知识，增进Java语言编辑基本功，掌握JDK、JCreator等开发工具的运用，拓宽常用类库的应用。使我们通过该教学环节与手段，把所学课程及相关知识加以融会贯通，全面掌握Java语言的编程思想及面向对象程序设计的方法，为今后从事实际工作打下坚实的基础。 2．具体实现 2.1设计思路 Java是一种简单的，面向对象的，分布式的，解释的，键壮的，安全的，结构中立的，可移植的，性能很优异的，多线程的，动态的语言。Java去掉了C++语言的许多功能，让Java的语言功能很精炼，并增加了一些很有用的功能，如
自动收集碎片。这将减少平常出错的50%。而且，Java很小，整个解释器只需215K的RAM。 因此运用JAVA程序编写小时钟程序，实现简单显示时间的功能。本次课程设计做的是Java简单小时钟，它是图形界面、线程、流与文件等技术的综合应用，其界面主要采用了java.awt包,javax.swing包等。程序实现了小时钟的基本功能。 2.2设计方法 在设计简单小时钟时，需要编写5个Java源文件：Server.java、Objecting.java、LogIn.java、ClientUser.java、Client.java。 小时钟除了需要编写的上述5个Java源文件所给出的类外，还需要Java系统提供的一些重要的类，如JTextField、JTextArea和File类。 2.3 运行环境 CPU：Pentium 2.8GHz以上 内存：256MB以上 硬盘空间：80G以上 操作系统：Windows XP 运行环境：JDK，JCreator 2.4 程序功能图及程序相关说明 2.4.1 主功能框
软件设计模式（Java版）习题 第1章软件设计模式基础 1.1 软件设计模式概述 1.2 UML中的类图 1.3 面向对象的设计原则 一、名词解释 1.一个软件实体应当对扩展开放，对修改关闭，即在不修改源代码的基础上扩展 一个系统的行为。 2.一个对象应该只包含单一的职责，并且该职责被完整地封装在一个类中。 3.在软件中如果能够使用基类对象，那么一定能够使用其子类对象。 4.是一套被反复使用、多数人知晓的、经过分类编目的、代码设计经验的总结， 使用设计模式是为了可重用代码、让代码更容易被他人理解、保证代码可靠性。 二、单选择题 1.( A ) 2.（ A ） 3. ( A ) 4. ( D ) 5. ( D ) 6．( A ) 7. ( D ) 8.（ D ） 9.（ D ） 10.（ E ） 11.( C ) 12．（ C ） 13. ( A ) 三、多选择题 1．( A、B、C、D ) 2. ( A、B ) 3．( A、D ) 4．( A、B、C、D ) 四、填空题 1．依赖倒转、迪米特法则、单一职责 2．模式名字、目的、问题、解决方案、效果、实例代码 3．超类、子类 4．开闭 5．用户 6．依赖倒转 7．组合/聚合 8．结构型、行为型 9.依赖倒转 10.开闭 11.需求收集是否正确、体系结构的构建是否合理、测试是否完全 12．人与人之间的交流 13．接口 14．名称、目的、解决方案 15．对象组合、类继承
16．对象组合 17．对象组合、类继承 18．抽象类的指针 五、简答题 1.答：设计模式按类型分为以下三类： 1）创建型设计模式：以灵活的方式创建对象集合，用于管理对象的创建。 2）结构型设计模式：将己有的代码集成到新的面向对象设计中，用于处理类或对象的组合。 3）行为型设计模式：用于描述对类或对象怎样交互和怎样分配职责。 2.答：设计模式的主要优点如下： 1）设计模式融合了众多专家的经验，并以一种标准的形式供广大开发人员所用，它提供了一套通用的设计词汇和一种通用的语言以方便开发人员之间沟通和交 流，使得设计方案更加通俗易懂。 2）设计模式使人们可以更加简单方便地复用成功的设计和体系结构，将已证实的技术表述成设计模式也会使新系统开发者更加容易理解其设计思路。设计模式使得重用成功的设计更加容易，并避免那些导致不可重用的设计方案。 3）设计模式使得设计方案更加灵活，且易于修改。 4）设计模式的使用将提高软件系统的开发效率和软件质量，且在一定程度上节约设计成本。 5）设计模式有助于初学者更深入地理解面向对象思想，一方面可以帮助初学者更加方便地阅读和学习现有类库与其他系统中的源代码，另一方面还可以提高软件的设计水平和代码质量。 3.答：设计模式一般有如下几个基本要素：模式名称、问题、目的、解决方案、效 果、实例代码和相关设计模式，其中的关键元素包括模式名称、问题、解决方案和效果。 4.答：正确使用设计模式具有以下优点： ⑴可以提高程序员的思维能力、编程能力和设计能力。 ⑵使程序设计更加标准化、代码编制更加工程化，使软件开发效率大大提高，从 而缩短软件的开发周期。 ⑶使设计的代码可重用性高、可读性强、可靠性高、灵活性好、可维护性强。 5.答：根据类与类之间的耦合度从弱到强排列，UML中的类图有以下几种关系：依赖关 系、关联关系、聚合关系、组合关系、泛化关系和实现关系。其中泛化和实现的耦合度相等，它们是最强的。
枣庄学院 信息科学与工程学院 课程设计任务书 题目：java人事管理系统 学号：0153 姓名：XXX 专业：计算机科学与技术 课程：java程序设计 指导教师：XXX 职称：讲师完成时间：2012 年 5 月----2012 年 6 月枣庄学院信息科学与工程学院制
课程设计任务书及成绩评定
目录
第1章概述 前言 1.1.1 背景 随着计算机技术的飞速发展，计算机在企业管理中应用的普及，利用计算机在实现企业人事档案的管理势在必行。当今社会正快速向信息化社会前进，信息自动化的作用也越来越大。从而使我们从繁杂的事务中解放出来，提高了我们的工作效率。目前很多企业的人事管理还处于人工管理的阶段，效率低下，已经远远落后于当今技术的发展。并且人工管理的弊端也愈来愈严重，由于不可避免的人为因素，造成数据的遗漏、误报，而造成企业重大损失的事例层出不穷。计算机信息化管理有着储存信息量大，速度快等许多优点，提供给我们的处理信息及时快捷，同时也提高了我们工作人员的自身素质。因此我们利用计算机提供给我们信息，做出了这个人事信息管理系统。人事管理系统是现在企业管理工作不可缺少的一部分，是适应现在企业制度的要求，是推动企业劳动人事走向科学化、规范化的必要条件。 传统的办公模式主要以纸介质为主，在信息革命的浪潮中，显然已经远远不能满足高效率、快节奏的现代工作和生活的需要。如何实现信息处理的自动化和办公的无纸化逐步得到了人们的重视。如今，随着计算机技术的普及人们开始采用一系列的计算机语言编写程序开发人事管理系统，它实现了办公地自动化，能使企业运行的数据更加准确、及时、全面、详实，同时对各种信息进一步地加工，使企业领导层对生产、经营的决策依据更充分，更具有合理性科学性，并创造出更多的发展机会；另外也进一步加强企业的科学化、合理化、制度化、规范化管理，为企业的管理水平跨上新台阶，为企业持续、健康、稳定的发展打下基础。本文主要介绍一个简单的基于Java的企业人事管理系统的实现，系统开发的总体任务是实现企业人事信息关系的系统化、规范化和自动化。
package com.lw; import java.awt.BorderLayout; import java.awt.EventQueue; import java.awt.Font; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import java.util.Calendar; import java.util.GregorianCalendar; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.SwingConstants; import javax.swing.UIManager; import javax.swing.border.EmptyBorder; public class DigitalClock extends JFrame { /** * */ private static final long serialV ersionUID = 4962111797317773666L; private JPanel contentPane; private JLabel label; /** * Launch the application. */ public static void main(String[] args) { try { UIManager.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel"); } catch (Throwable e) { e.printStackTrace(); } EventQueue.invokeLater(new Runnable() { public void run() { try { DigitalClock frame = new DigitalClock(); frame.setV isible(true); } catch (Exception e) { e.printStackTrace(); }
1. 使用简单工厂模式设计一个可以创建不同几何形状（Shape），如圆形（Circle）、矩形（Rectangle）的绘图工具工厂类，每个几何图形均有绘制draw()和擦除erase()两个方法，要求在绘制不支持的几何图形时，抛出一个UnSupportedShapeException。绘制类图并编程模拟实现。 代码实现 Shape.java Circle.java
Rectangle.java ShapeFactory.java UnSupportedShapeException.java Test.java
如果向工厂类传入参数“circle”，则返回一个Circle对象，如果传入参数“rectangle”，则返回一个Rectangle对象。现需要增加一个新的三角形Triangle类，如果传入参数“triangle”，则返回一个Triangle对象，对代码进行修改并注意工厂类的变化。 添加一个Triangle类 Triangle.java ShapeFactory类的代码，违背了开闭原则。 ShapeFactory.java
Assert.java 2. 现需要设计一个程序来读取多种不同类型的图片格式，针对每一种图片格式都设计一个图片读取器(ImageReader)，如GIF图片读取器(GifReader)用于读取GIF格式的图片、JPG 图片读取器(JpgReader)用于读取JPG格式的图片，所有的图片读取器都有读取图片的方法readImage()。图片读取器对象通过图片读取器工厂ImageReaderFactory来创建，ImageReaderFactory是一个抽象工厂接口，定义了创建图片读取器的工厂方法createImageReader()，其实现类GifReaderFactory用于创建GIF图片读取器(GifReader)对象，
目录 1前言 (2) 1.1信息化的进展 (2) 1.2课题的研究背景 (2) 1.3课题的研究目的 (3) 2需求分析 (3) 2.1 可行性分析 (4) 2.1.1 经济可行性 (4) 2.1.2 技术可行性 (4) 2.1.3 运行可行性 (4) 2.2系统需求 (5) 2.3功能需求 (5) 2.4性能需求 (5) 3概要设计 (6) 3.1系统开发环境 (6) 3.2 JDK 1.6和Tomcat 6.0 服务器配置 (6)
3.3系统结构图 (7) 3.4治理端流程图 (8) 3.5客户端流程图 (9) 3.6数据库设计 (9) 3.6.1数据库E-R图设计 (9) 3.6.2实体图设计 (10) 3.6.3数据库表设计 (13) 4详细设计 (15) 4.1登陆界面设计 (15) 4.2部门治理模块设计 (16) 4.3职工治理模块设计 (17) 4.3.1职工列表模块设计 (17) 4.3.2职工查询模块设计 (18) 4.4事务治理设计 (18) 4.4.1考勤治理模块设计 (18) 4.4.2请假治理模块设计 (19) 4.4.3工资治理模块设计 (20)
4.4.4加班治理模块设计 (20) 4.5帐号治理设计 (21) 4.5.1治理员模块设计 (21) 4.5.2用户模块设计 (21) 5调试与测试 (22) 5.1程序调试 (22) 5.2程序的测试 (22) 5.2.1测试的重要性和目的 (22) 5.2.2测试方法设计 (23) 5.2.3测试的用例设计 (23) 6总结 (24) 参考文献 (25) 致谢 (25)
package pkg110; import java.awt.*; import java.awt.event.*; import java.util.*; import javax.swing.*; import javax.swing.Timer; /** * * @author Administrator */ public class Clock extends JFrame implements ActionListener{ public final int HEIGTH = 200, L0 = 50, T0 = 50,N=8; public final double RAD = Math.PI / 180.0; int x, y, old_X, old_Y, r, x0, y0, w, h, ang; int sdo, mdo, hdo, old_M, old_H, hh, mm, ss; int delay = 1000; Calendar now; String st, alarm, Items1, Items2,str[]; JButton jb; JComboBox jc1, jc2, jc3; JLabel jl1, jl2, jl3, jl4; JTextField jtf1, jtf2, time; JPanel jp1, jp2, jp3; Timer timer; TimeZone tz = TimeZone.getTimeZone("JST"); Toolkit toolkit=Toolkit.getDefaultToolkit(); /** * @param args the command line arguments */ public static void main(String[] args) { // TODO code application logic here Clock cp = new Clock(); cp.setVisible(true); } Clock() { super("闹钟"); setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); setSize(400,550); setVisible(true); Container contentPane = getContentPane(); jp2 = new JPanel(); jl1 = new JLabel("闹铃时间");
学校代码：11517 学号：2 文献综述 题目基于的人事管理系统 的设计与实现 学生姓名许耀辉 专业班级信息与计算科学1042班 学号 2 系（部）理学院 指导教师(职称)董西广(讲师) 完成时间2014年3月4日
基于的人事管理系统的设计与实现 摘要：随着计算机的发展，科技的发展，现阶段的人事管理系统越来越不能满足企业的需要，特别是对于一些企业仍然采用人工管理的方式，这种方式不仅增加了企业的成本，而且极其容易出错，设计一种基于的人事管理系统就应运而生了，人事管理系统基本实现了企业人事管理的基本应用，包括人事信息管理的增、删、改、查，考勤信息管理的增、删、改、查，个人简历信息管理等基本应用，设计的人事管理涉及数据库的操作，以及数据库的连接等相关知识。 关键词：人事管理 1 引言 21世纪最激烈的竞争当属人才的竞争，一个具有多学科知识的复合性人才或许是一个企业发展壮大所不可或缺的重要因素。因此人力资源已逐步成为企业最重要的资源，人力资源管理（，）也成为现代企业管理工作中的重要内容之一。随着社会的发展，科技的进步，计算机的应用在社会各领域中都得到了普及，越来越多的人都感受到利用计算机进行各类管理的科学和便捷；认识到管理信息系统对于管理工作的重要性[1]。 本次论文创作的主要目的是设计一款简单、易操作的现代人事管理系统，在论文创作的过程中，我借助学校和个人收集的相关资料，利用图书馆和网络等渠道，广泛查阅相关资料，分析前人成果的基础上，明确系统设计思路。 2 人事管理系统的发展 2.1人事管理系统的国外的发展 人事管理系统的发展经过三个阶段的发展。 人事管理系统的发展历史可以追溯到20世纪60年代末期。由于当时计算机技术已经进入实用阶段，同时大型企业用手工来计算和发放薪资既费时费力又容易出差错，为了解决这个矛盾，第一代人事管理系统应运而生。 第二代的人事管理系统出现于20世纪70年代末。由于计算机技术的飞速发展，无论是计算机的普及性，还是计算机系统工具和数据库技术的发展，都为的