/***  compareTo 方法必须提供与 getDelay 方法一致的排序*/
class MyDelayedTask implements Delayed{private String name ;private long start = System.currentTimeMillis();private long time ;public MyDelayedTask(String name,long time) {this.name = name;this.time = time;}/*** 需要实现的接口，获得延迟时间   用过期时间-当前时间* @param unit* @return*/@Overridepublic long getDelay(TimeUnit unit) {return unit.convert((start+time) - System.currentTimeMillis(),TimeUnit.MILLISECONDS);}/*** 用于延迟队列内部比较排序   当前时间的延迟时间 - 比较对象的延迟时间* @param o* @return*/@Overridepublic int compareTo(Delayed o) {MyDelayedTask o1 = (MyDelayedTask) o;return (int) (this.getDelay(TimeUnit.MILLISECONDS) - o.getDelay(TimeUnit.MILLISECONDS));}@Overridepublic String toString() {return "MyDelayedTask{" +"name='" + name + '\'' +", time=" + time +'}';}
}

private static DelayQueue delayQueue  = new DelayQueue();public static void main(String[] args) throws InterruptedException {new Thread(new Runnable() {@Overridepublic void run() {delayQueue.offer(new MyDelayedTask("task1",10000));delayQueue.offer(new MyDelayedTask("task2",3900));delayQueue.offer(new MyDelayedTask("task3",1900));delayQueue.offer(new MyDelayedTask("task4",5900));delayQueue.offer(new MyDelayedTask("task5",6900));delayQueue.offer(new MyDelayedTask("task6",7900));delayQueue.offer(new MyDelayedTask("task7",4900));}}).start();while (true) {Delayed take = delayQueue.take();System.out.println(take);}}

MyDelayedTask{name='task3', time=1900}
MyDelayedTask{name='task2', time=3900}
MyDelayedTask{name='task7', time=4900}
MyDelayedTask{name='task4', time=5900}
MyDelayedTask{name='task5', time=6900}
MyDelayedTask{name='task6', time=7900}
MyDelayedTask{name='task1', time=10000}

static class Task implements Delayed{@Override//比较延时，队列里元素的排序依据public int compareTo(Delayed o) {return 0；}@Override//获取剩余时间public long getDelay(TimeUnit unit) {return 0；}}

import java.sql.Time;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.DelayQueue;
import java.util.concurrent.Delayed;
import java.util.concurrent.TimeUnit;public class Delayquue {public static void main(String[] args) throws Exception {BlockingQueue<Task> delayqueue = new DelayQueue<>();long now = System.currentTimeMillis();delayqueue.put(new Task(now+3000));delayqueue.put(new Task(now+4000));delayqueue.put(new Task(now+6000));delayqueue.put(new Task(now+1000));System.out.println(delayqueue);for(int i=0; i<4; i++) {System.out.println(delayqueue.take());}}static class Task implements Delayed{long time = System.currentTimeMillis();public Task(long time) {this.time = time;}@Overridepublic int compareTo(Delayed o) {if(this.getDelay(TimeUnit.MILLISECONDS) < o.getDelay(TimeUnit.MILLISECONDS))return -1;else if(this.getDelay(TimeUnit.MILLISECONDS) > o.getDelay(TimeUnit.MILLISECONDS)) return 1;else return 0;}@Overridepublic long getDelay(TimeUnit unit) {return unit.convert(time - System.currentTimeMillis(),TimeUnit.MILLISECONDS);}@Overridepublic String toString() {return "" + time;}}
} 

offer方法

1. 执行加锁操作
2. 吧元素添加到优先级队列中
3. 查看元素是否为队首
4. 如果是队首的话，设置leader为空，唤醒所有等待的队列
5. 释放锁

代码如下：