倒计时关机案例

package com.hp.demo05;

import java.util.Date;

public class Demo02 {
    public static void main(String[] args) throws Exception{
        int s = 60;

        //60秒后的时间
        Date mb = new Date();
        mb.setMinutes(mb.getMinutes()+1);//原有分钟+1900
        long a = mb.getTime();

        while (true) {
            Date now = new Date();//当前时间
            long b = now.getTime();//
             long c = a-b;
             if (c==0){
                 System.out.println("时间到了,开始关机...");
                 Runtime runtime = Runtime.getRuntime();
                 runtime.exec("shutdown -s -t 60 -f");
                 break;
            }
                System.out.println("剩余"+c/1000+"秒关机");
             Thread.sleep(1000);
        }

    }
}