Java实现Redis的消息订阅和发布

1.  首先需要一个消息监听器类

package com.sogou.baike.testimport.testSubscribe;

import redis.clients.jedis.JedisPubSub;

/**
 * Created by denglinjie on 2016/6/29.
 */
public class RedisMsgPubSubListener extends JedisPubSub {
    @Override
    public void unsubscribe() {
        super.unsubscribe();
    }

    @Override
    public void unsubscribe(String... channels) {
        super.unsubscribe(channels);
    }

    @Override
    public void subscribe(String... channels) {
        super.subscribe(channels);
    }

    @Override
    public void psubscribe(String... patterns) {
        super.psubscribe(patterns);
    }

    @Override
    public void punsubscribe() {
        super.punsubscribe();
    }

    @Override
    public void punsubscribe(String... patterns) {
        super.punsubscribe(patterns);
    }

    @Override
    public void onMessage(String channel, String message) {
        System.out.println("channel:" + channel + "receives message :" + message);
        this.unsubscribe();
    }

    @Override
    public void onPMessage(String pattern, String channel, String message) {

    }

    @Override
    public void onSubscribe(String channel, int subscribedChannels) {
        System.out.println("channel:" + channel + "is been subscribed:" + subscribedChannels);
    }

    @Override
    public void onPUnsubscribe(String pattern, int subscribedChannels) {

    }

    @Override
    public void onPSubscribe(String pattern, int subscribedChannels) {

    }

    @Override
    public void onUnsubscribe(String channel, int subscribedChannels) {
        System.out.println("channel:" + channel + "is been unsubscribed:" + subscribedChannels);
    }
}

该类需要继承 JedisPubSub ，并实现其抽象方法，通过方法的名称很清楚的看出来，这个监听器是用来订阅一个频道，在订阅该频道，取消订阅，收到消息等状态会对应调用相关的方法

2.  订阅测试类

public class TestSubscribe {
    @Test
    public void testSubscribe() throws Exception{
        Jedis jedis = new Jedis("localhost");
        RedisMsgPubSubListener listener = new RedisMsgPubSubListener();
        jedis.subscribe(listener, "redisChatTest");
        //other code
    }
}

该类实现对频道redisChatTest的订阅监听，频道的订阅，取消订阅，收到消息都会调用listener对象的对应方法

注意：subscribe是一个阻塞的方法，在取消订阅该频道前，会一直阻塞在这，只有当取消了订阅才会执行下面的other code，参考上面代码，我在onMessage里面收到消息后，调用了this.unsubscribe(); 来取消订阅，这样才会执行后面的other code

3.  发布消息测试类

Public class TestPublish {
    @Test
    public void testPublish() throws Exception{
        Jedis jedis = new Jedis("localhost");
        jedis.publish("redisChatTest", "我是天才");
        Thread.sleep(5000);
        jedis.publish("redisChatTest", "我牛逼");
        Thread.sleep(5000);
        jedis.publish("redisChatTest", "哈哈");
    }
}

这个类向频道redisChatTest发布消息，第二步因为订阅了该频道，所以会收到该消息。