StackByArray/src/com/example/ArrayList/currentTime.java

package com.example.ArrayList;


import java.util.ArrayList;
import java.util.Random;

public class currentTime{
    /*
     * 
     * 测试时间戳类
     */
    public static void main(String[] args) {
        ArrayList<Integer> arrayList = new ArrayList<>();
        long start = System.currentTimeMillis(); 
        System.out.println("开始时间："+start);
        try {
            Thread.sleep(5000); 
            Random random = new Random();
            for (int i = 0; i <= 20; i++) {
                // 循环，生成随机数
                arrayList.add(random.nextInt(20) + 1);
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        long end = System.currentTimeMillis(); 
        System.out.println(end - start+"毫秒"); 
    }

}