StringBuffer类和String类的效率对比

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处理字符串的StringBuffer类和String类时间效率对比。主要用到了System.currentTimeMillis();、append(); 。我的java学习日记，不是技术文档哦。-- gt.liu - 20160321

测试代码如下：

//对比StringBuffer和String 的执行效率import java.util.*;public class Demo032003{    public static void main(String [] args){        //为了明显地看出两者的执行效率，分别将26个字母相加1000次        String aaa = "abcdefghijklmnopqrstuvwxyz";        int count = 1000;//叠加次数        //String        long timestart1 = System.currentTimeMillis();        //System.out.println("timestart1 = " + timestart1 );//test currentTimeMillis();        String str1 = "";        for( int i = 0; i < count; i++ )            str1 += aaa;        long timeend1 = System.currentTimeMillis();        System.out.println( "time1 = " + (timeend1 - timestart1) + "ms" );        //StringBuffer        long timestart2 = System.currentTimeMillis();        StringBuffer str2 = new StringBuffer();        for( int i = 0; i < count; i++ )            str2.append(aaa);        long timeend2 = System.currentTimeMillis();        System.out.println( "time2 = " + (timeend2 - timestart2) + "ms" );    }}

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