package com.test;

import java.util.Date;

public class Main {
    public static void main(String[] args) {
        long now = new Date().getTime();
        String s1 = "";
        int n = 100000;
        StringBuilder s2 = new StringBuilder();
        StringBuffer s3 = new StringBuffer();
        for (int i = 0; i < n; i++) {
            s1 += "."+i;
        }
        System.out.println("String使用的時間"+(System.currentTimeMillis()-now)/1000.0+"s");
        long time1 = System.currentTimeMillis();
        for (int i = 0; i < n; i++) {
            s2.append("."+i);
        }
        System.out.println("StringBuilder使用的時間"+(System.currentTimeMillis()-time1)/1000.0+"s");
        long time2 = System.currentTimeMillis();
        for (int i = 0; i < n; i++) {
            s3.append("."+i);
        }
        System.out.println("StringBuffer使用的時間"+(System.currentTimeMillis()-time2)/1000.0+"s");
    }
}

 

說實話有點被震驚到了，當迴圈次數到十萬的時候，String不是慢了一點罷點。