JAVA值传递与引用传递

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package com.bobo;

/**
* Created by IntelliJ IDEA.
* User:<a href="mailto:[e-mail]">波波</a>
* QQ:15221860
* Date: 2006-12-17
* Time: 0:03:52
*/
public class User {
private int age;

public int getAge() {
return age;
}

public void setAge(int age) {
this.age = age;
}
}

package com.bobo;

/**
* Created by IntelliJ IDEA.
* User:<a href="mailto:[e-mail]">波波</a>
* QQ:15221860
* Date: 2006-12-16
* Time: 23:51:14
*/
public class Value {

public static void main(String[] args) {
int testValue = 0;
changeValueFalse(testValue);
System.out.println(testValue);

String testValue1 = "0";
changeValueTrue(testValue1);
System.out.println(testValue1);

User user = new User();
user.setAge(0);
changeValueReference(user);
System.out.println(user.getAge());

}

public static void changeValueFalse(int value) {
value = 100;
}

public static void changeValueTrue(String value) {
value = "100";
}

public static void changeValueReference(User user) {
user.setAge(user.getAge() + 100);
}

}

IDEA运行结果是：

D:\ProgramJava\Java\jdk1.5.0_09\bin\java -Didea.launcher.port=7534 "-Didea.launcher.bin.path=D:\ProgramJava\JetBrains\IntelliJ IDEA 6.0\bin" -Dfile.encoding=UTF-8 -classpath "D:\ProgramJava\Java\jdk1.5.0_09\jre\lib\charsets.jar;D:\ProgramJava\Java\jdk1.5.0_09\jre\lib\deploy.jar;D:\ProgramJava\Java\jdk1.5.0_09\jre\lib\javaws.jar;D:\ProgramJava\Java\jdk1.5.0_09\jre\lib\jce.jar;D:\ProgramJava\Java\jdk1.5.0_09\jre\lib\jsse.jar;D:\ProgramJava\Java\jdk1.5.0_09\jre\lib\plugin.jar;D:\ProgramJava\Java\jdk1.5.0_09\jre\lib\rt.jar;D:\ProgramJava\Java\jdk1.5.0_09\jre\lib\ext\dnsns.jar;D:\ProgramJava\Java\jdk1.5.0_09\jre\lib\ext\localedata.jar;D:\ProgramJava\Java\jdk1.5.0_09\jre\lib\ext\sunjce_provider.jar;D:\ProgramJava\Java\jdk1.5.0_09\jre\lib\ext\sunpkcs11.jar;C:\Documents and Settings\bobo\IdeaProjects\untitled1\classes\test\untitled1;C:\Documents and Settings\bobo\IdeaProjects\untitled1\classes\production\untitled1;D:\ProgramJava\JetBrains\IntelliJ IDEA 6.0\lib\idea_rt.jar" com.intellij.rt.execution.application.AppMain com.bobo.Value

0
0
100

Process finished with exit code 0

所以可以看出：

changeValueFalse(testValue);

changeValueTrue(testValue1);
调用以后传入的值没有改变依旧啊0，”0“
changeValueReference(user);
传入前user对象的年龄是0执行以后是100，改变了

通过这三个希望大家理解：

JAVA基本类型

String类

以及其他类的方法调用的实质

其实与C语言类似，基本类型是值拷贝所以修改的是方法内部的值在方法结束以后拷贝的值虽然变化但是没有回带，所以原来值依旧

而User是引用传递其实可以理解是指针或者地址传递，修改的是指向，所以变化

String大家是怎么理解，希望大家思考啊，提示JAVA的String有点特殊哦