package com.liu.demo1;
//验证StringBuilder效率比String高
public class Demo2 {
    public static void main(String[] args) {
        long start =System.currentTimeMillis();//开始时间
        //String string ="";
       // for (int i = 0; i < 10000; i++) {
       //     string+=i;//字符串拼接不是计算
       // }
       // System.out.println(string);  用时230毫秒

        StringBuilder sb =new StringBuilder();
        for (int i = 0; i < 10000; i++) {
            sb.append(i);
        }
        System.out.println(sb.toString());
        long end = System.currentTimeMillis(); //0毫秒
        System.out.println(end-start);
    }
}