SUN JDK6环境,测试String累加测试,以便比较字符串连接的效率问题class StrConcatTest{public static void main(String[] args) {long t1 = System.currentTimeMillis();long i=0;long l=20000;String tmp ="测试字d";String ret = "";StringBuilder sb = new StringBuilder();while(i<l){// 1. ret+=tmp;// 2. ret=ret.concat(tmp);//3. sb.append(tmp);i++;}long t2 = System.currentTimeMillis();System.out.println(ret.length()); // 3. System.out.println(sb.toString().length());System.out.println(t2-t1);}}结果如下:(命令行第二行为执行毫秒数)1.直接用'+'连接字符串2.用String.concat()方法连接字符串3.用StringBuilder类方法追加字符串http://www.txdnet.cn/essay/view.jsp?tid=1270481150604&cid=2

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