不要再困扰在String与StringBuffer(StringBuilder)的区别上鸟

无论是初学者还是在java这条路上游荡了几年的童鞋都会每每想起String与StringBuffer的区别这个话题！今天再次看见这个话题，该是终结的时候咯！

原文：[url=http://www.iteye.com/topic/142364#422534]http://www.iteye.com/topic/142364#422534[/url]


看原文后我的总结：

java常量池：[url=http://wenku.baidu.com/view/4a2f961c59eef8c75fbfb348.html]http://wenku.baidu.com/view/4a2f961c59eef8c75fbfb348.html[/url]

[color=red]注意为对象在堆中编写的地址变化以及不变化哦[/color]
.
1.将textString定义为局部变量

[img]http://dl.iteye.com/upload/picture/pic/93362/c65a09db-b4e2-3e7a-abd7-4051b0529f4a.jpg[/img]

public class testStringStringBuffer {
   public static void stringReplace (String text) {    
   text = text.replace('j' , 'i');  
   System.out.println (text); 
   }    

   public static void bufferReplace (StringBuffer text) {    
   text = text.append("C");     
   }    

    public static void main (String args[]) {     
    String textString = new String ("java");     
    StringBuffer textBuffer = new StringBuffer ("java");     

    stringReplace (textString);     
    bufferReplace (textBuffer);     

    System.out.println (textString + textBuffer);     
    }     

}

输出结果：
iava 
javajavaC 

2.将textString定义为全局变量

[img]http://dl.iteye.com/upload/picture/pic/93360/cf43f454-d319-332a-a9b7-7beb4215b850.jpg[/img]

/**
 *@source:http://www.iteye.com/topic/142364#422534
 * 
 *@function:
 * 
 * @author ocaicai@yeah.net 2011-6-29
 * 
 */
public class testStringStringBuffer {

	static String textString = null;// 将textString定义为全局变量

	public static void stringReplace(String text) {
		//让textString指向在堆中新产生的对象
		textString = text.replace('j', 'i');
		System.out.println(textString);
	}

	public static void bufferReplace(StringBuffer text) {
		text = text.append("C");
	}

	public static void main(String args[]) {
		textString = new String("java");
		StringBuffer textBuffer = new StringBuffer("java");

		stringReplace(textString);
		bufferReplace(textBuffer);

		System.out.println(textString + textBuffer);
	}

}

输出结果：
iava
iavajavaC

[color=green]上面这个全局的效果等价于：[/color]

package com.cdl.mix;

/**
 *@source:http://www.iteye.com/topic/142364#422534
 * 
 *@function:
 * 
 * @author ocaicai@yeah.net 2011-6-29
 * 
 */
public class testStringStringBuffer {

	//static String textString = null;// 将textString定义为全局变量

//	public static void stringReplace(String text) {
//		//让textString指向在堆中新产生的对象
//		textString = text.replace('j', 'i');
//		System.out.println(textString);
//	}

	public static void bufferReplace(StringBuffer text) {
		text = text.append("C");
	}

	public static void main(String args[]) {
		String textString = new String("java");
		StringBuffer textBuffer = new StringBuffer("java");

		//stringReplace(textString);
		textString=textString.replace('j', 'i');
		System.out.println(textString);
		bufferReplace(textBuffer);

		System.out.println(textString + textBuffer);
	}

}

输出结果：
iava
iavajavaC

[size=xx-large][color=red]区别就是一句话：

String引用改变指向一个新的地址，

StringBuffer引用不变指向自己本身[/color][/size]