线程sleep休眠的应用

package com.Java;

import java.text.SimpleDateFormat;
import java.util.Date;

//每个对象都有一个锁 sleep不会释放锁
public class TestSleep {
    public static void main(String[] args) {
        try {
//            tendown();
            date();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    //10秒倒计时
    public static void tendown() throws InterruptedException {
        int num = 10;
        while (true) {
            Thread.sleep(1000);
            System.out.println(num--);
            if (num <= 0) {
                break;
            }
        }
    }

    //每秒更新时间
    public static void date() throws InterruptedException {
        Date date = new Date(System.currentTimeMillis());   //获取系统当前时间
        while (true) {
            Thread.sleep(1000);
            System.out.println(new SimpleDateFormat("HH:mm:ss").format(date));  //打印格式
            date = new Date(System.currentTimeMillis());    //更新当前时间
        }
    }
}