线程休眠——sleep

package com.pln.state;
import java.text.SimpleDateFormat;
import java.util.Date;
public class TestSleep {
    public static void main(String[] args) throws InterruptedException {
//        tenDown();
        //获取系统时间
        Date startTime = new Date(System.currentTimeMillis());
        while (true){
            Thread.sleep(1000);
            System.out.println(new SimpleDateFormat("HH:mm:ss").format(startTime));
            startTime = new Date(System.currentTimeMillis());//更新时间
        }
    }
    //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;
            }
        }
    }
}