String 和StringBuffer和StringBuilder区别

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1.与StringBuffer的区别:StringBuffer是线程安全的，StringBuider是线程不安全的

2. StringBuider的性能最快StringBuffer较为次之，String最慢。

3.StringBuider和StringBuffer是可变的字符序列

package ch3;public class StringText1 {public static void main(String[] args) {// TODO Auto-generated method stubStringBuffer str =new StringBuffer("你好吗！");str.append("你也好吗？");System.out.println(str);long begin =System.nanoTime();String s = "";for(int i=0; i<=5000;i++){s += i;}long end = System.nanoTime();System.out.println("String time:"+(end-begin));begin = System.nanoTime();StringBuffer sBuffer = new StringBuffer("");for(int i=0; i<=5000;i++){sBuffer.append(i);}end = System.nanoTime();System.out.println("StringBuffer time:"+(end-begin));begin = System.nanoTime();StringBuilder sBuilder= new StringBuilder("");for(int i=0; i<=5000;i++){sBuilder.append(i);}end = System.nanoTime();System.out.println("StringBuilder time:"+(end-begin));}}

结果：你好吗！你也好吗？
String time:52306271
StringBuffer time:836000
StringBuilder time:432754