利用DelayQueue实现延时消息队列（简易版MQ）

1.上文

关于阻塞队列的介绍：http://blog.csdn.net/caicongyang/article/details/50649897

2.需求

 延迟消息队列：

1)2个小时后给用户发送短信。
2)15分钟后关闭网络连接。
3)2分钟后再次尝试回调。

3.案例demo

Message.java

package com.ccy.concurrent;

import java.util.concurrent.Delayed;
import java.util.concurrent.TimeUnit;

/**
 * 
 
 * Title: Message.java 
 * Package com.ccy.concurrent 
 * 
 * 

 * Description: 延迟执行的消息
 * 

 * @author Tom.Cai
 * @created 2016-2-10 下午7:39:48 
 * @version V1.0 
 *
 */
public class Message implements Delayed{
		private String id;
		private String name;
		private long activeTime;//执行时间   
		
		public Message(){
			
		}
		
		public Message(String id, String name,long activeTime) {
			super();
			this.id = id;
			this.name = name;
			this.activeTime = TimeUnit.NANOSECONDS.convert(activeTime, TimeUnit.MILLISECONDS) + System.nanoTime();
		}
		public String getId() {
			return id;
		}
		public void setId(String id) {
			this.id = id;
		}
		public String getName() {
			return name;
		}
		public void setName(String name) {
			this.name = name;
		}

		@Override
		public int compareTo(Delayed delayed) {
			Message msg = (Message)delayed;
			return Integer.valueOf(this.id)>Integer.valueOf(msg.id)?1:( Integer.valueOf(this.id)

Producer.javaProducer

package com.ccy.concurrent;

import java.util.concurrent.DelayQueue;

public class Producer implements Runnable{
	private DelayQueue queue;
	
	public Producer(DelayQueue queue){
		this.queue = queue;
	}

	@Override
	public void run() {
		//5秒后发送消息
		Message m2 = new Message("2","Tom",5000);
		queue.offer(m2);
		System.out.println("消息生产者往消息队列放置消息："+m2.getId()+":"+m2.getName());
		//3秒后发送消息
		Message m1 = new Message("1","Tom",3000);
		queue.offer(m1);
		System.out.println("消息生产者往消息队列放置消息："+m1.getId()+":"+m1.getName());
		
	}
	

}

Consumer.java

package com.ccy.concurrent;

import java.util.concurrent.DelayQueue;

public class Consumer implements Runnable{
	private DelayQueue queue;
	
	public Consumer(DelayQueue queue){
		this.queue = queue;
	}
	
	@Override
	public void run() {
		while(true){
			try {
				Message take = queue.take();
				System.out.println("消息需求者获取消息："+take.getId()+":"+take.getName());
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
	}

}

DelayQueueTest.java

package com.ccy.concurrent;

import java.util.concurrent.DelayQueue;


public class DelayQueueTest {
	public static void main(String[] args) {
		DelayQueue queue = new DelayQueue();
		new Thread(new Producer(queue)).start();
		new Thread(new Consumer(queue)).start();
	}
}

4.效果

5.其他学习资源

http://zhangyp.net/rabbitmq-delayqueue/

...

6.后记

作者将学习Apache的ActiveMQ消息总线，其可以支持定时、延迟投递、重复投递和Cron调度。

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