String 和StringBuilder字符串操作快慢的举例比较

System.currentTimeMillis();
//当前时间与1970年1月1日午夜UTC之间的毫秒差。

public class HelloWorld {public static void main(String[] args) {String s1 = "";StringBuilder s2 = new StringBuilder("");long time = System.currentTimeMillis();long spendTime;int n = 100000;for (int i = 0; i < n; i++) {s1 += "abc";}spendTime = System.currentTimeMillis()-time;System.out.println(spendTime/1000.0 + "s");//String操作花费的时间time = System.currentTimeMillis();for (int i = 0; i < n; i++) {s2.append("abc");}spendTime = System.currentTimeMillis()-time;System.out.println(spendTime/1000.0 + "s");//StringBuilder操作花费的时间}
}

StringBuilder明显快于String。