Java中的定时器以及自己实现定时器

Java中的定时器

代码实现

package 使用Java中定时器;

import java.util.Timer;
import java.util.TimerTask;

public class TimeOutDemo {
    
    
    public static void main(String[] args) throws InterruptedException {
    
    
        //TimerTask:让定时器去运行任务
        //Timer:定时器

        TimerTask task = new TimerTask() {
    
    
            @Override
            public void run() {
    
    
                System.out.println("时间到了，该起床了");
            }
        };

        Timer timer = new Timer();
        //timer.schedule(task,5000);//5秒之后去执行任务
        timer.scheduleAtFixedRate(task,5000,3000);//5秒之后闹钟第一次响，然后之后就是每三秒响

        while (true){
    
    
            System.out.println("我是主线程，我在睡觉");
            Thread.sleep(5000);
        }
    }
}

2.自己实现定时器

package 定时器实现的最简单版本;

public class MyTimer {
    
    
    static abstract class TimerTask{
    
    
        public abstract void run();
    }
    static class Timer{
    
    
        public void schedule(TimerTask task,long delay){
    
    
            Thread thread = new Thread(){
    
    
                @Override
                public void run() {
    
    
                    try {
    
    
                        Thread.sleep(delay);
                        task.run();
                    } catch (InterruptedException e) {
    
    
                        e.printStackTrace();
                    }
                }
            };
            thread.start();
        }
    }

    public static void main(String[] args) throws InterruptedException {
    
    
        Timer timer = new Timer();
        timer.schedule(new TimerTask(){
    
    
            @Override
            public void run() {
    
    
                System.out.println("时间到了，干活!");
            }
        },5000);

        while (true){
    
    
            System.out.println("我是主线程");
            Thread.sleep(5000);
        }
    }
}