/*** StringBuilder 和 String拼接10万个字符串的速度测试差别太大了* String耗时毫秒: 32693* StringBuilder耗时毫秒: 16*/
public class Demo7 {public static void main(String[] args) {long lsg = getString();System.out.println("String耗时毫秒: " + lsg);long sb = getSb();System.out.println("StringBuilder耗时毫秒: " + sb);System.out.println("String 比 StringBuilder多用耗时:" + (lsg - sb));}/*** StringBuilder 拼接十万个字符串的耗时* @return*/private static long getSb() {//起始时间long start = System.currentTimeMillis();StringBuilder sb = new StringBuilder();for (int i = 0; i <= 100000; i++) {sb.append(i);}//结束时间long end = System.currentTimeMillis();//返回共用耗时毫秒return end - start;}/*** string 拼接十万个字符串的耗时* @return 返回共用耗时毫秒*/private static long getString() {//起始时间long start = System.currentTimeMillis();String str = "";for (int i = 0; i <= 100000; i++) {str += i;}//结束时间long end = System.currentTimeMillis();//返回共用耗时毫秒return end - start;}
}