Java多线程中的定时器（java.util.Timer）有定时执行任务的功能，通过设定定时器的间隔时间，会自动在此间隔后执行预先安排好的任务（java.util.TimerTask）。
timer.schedule(TimerTask,delay,interval time)
第一个参数是需要执行的任务。此类的类型为java.util.TimerTask。第二个参数是执行任务前等待时间，第三个参数是间隔时间（单位为毫秒）

package timer;

import java.util.concurrent.PriorityBlockingQueue;

public class MyTimer {
PriorityBlockingQueue<MyTimerTask> queue = new PriorityBlockingQueue<>();
Worker worker;

private static class Worker extends Thread { PriorityBlockingQueue<MyTimerTask> queue; Worker(PriorityBlockingQueue<MyTimerTask> queue) { this.queue = queue; } @Override public void run() { while (true) { try { MyTimerTask task = queue.take(); long current = System.currentTimeMillis(); if (task.delay <= current) { task.target.run(); } else { queue.put(task); Thread.sleep(task.delay - current); } } catch (InterruptedException e) { e.printStackTrace(); } } }}MyTimer() { worker = new Worker(queue); worker.start();}void execute(Runnable target, long delay) { queue.put(new MyTimerTask(target, delay));}public static void main(String[] args) { MyTimer timer = new MyTimer(); timer.execute(new Runnable() { @Override public void run() { System.out.println("该起床了"); } }, 2000); System.out.println("另一个人");}

}
package timer;

public class MyTimerTask implements Comparable<MyTimerTask> {
Runnable target;
long delay;

MyTimerTask(Runnable target, long delay) { this.target = target; this.delay = System.currentTimeMillis() + delay;//延时后的时刻}@Overridepublic int compareTo(MyTimerTask o) { if (delay == o.delay) {//延时后的时刻 return 0; } else if (delay < o.delay) { return -1; } else { return 1; }}

}