springboot结合redis实现redis订阅发布模式

redis订阅发布模式：

Redis提供了发布订阅功能，可以用于消息的传输，Redis的发布订阅机制包括三个部分，发布者，订阅者和Channel。 

发布者和订阅者都是Redis客户端，Channel则为Redis服务器端，发布者将消息发送到某个的频道，订阅了这个频道的订阅者就能接收到这条消息。Redis的这种发布订阅机制与基于主题的发布订阅类似，Channel相当于主题。

实现功能：

通过网页访问一个网址的时候实现redis在某个频道的的发布，同时订阅了该频道的redis订阅者会做出相应的反应。

要想让redis在web容器开启时就一直处于订阅状态，考虑通过listener来实现：

Listener：

@Configuration
@WebListener
public class MyListenerOnServlet implements ServletContextListener{
    @Override
    public void contextInitialized(ServletContextEvent servletContextEvent) {
        System.out.println("ServletContext容器初始化了。。。");
        Thread threadOnRedis = new TestSubscribe();
        threadOnRedis.start();

    }

    @Override
    public void contextDestroyed(ServletContextEvent servletContextEvent) {
        System.out.println("ServletContext容器销毁了。。。");
    }

}

TestSubScribe线程类：

public class TestSubscribe extends Thread {


    @Override
    public void run() {
        JedisShardInfo jedisShardInfo = new JedisShardInfo("127.0.0.1", 6379);
        jedisShardInfo.setPassword("admin");
        Jedis jedis = new Jedis(jedisShardInfo);
        RedisMsgPubSubListener listener = new RedisMsgPubSubListener();
        jedis.subscribe(listener, "redisChatTest");
        System.out.println("不阻塞");
    }
}

RedisMsgPubSubListener类：

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);
    }


}

通过controller的访问来触发redis的发布：

Controller：

@RequestMapping("/t07")
    public String test07(@RequestParam("msg") String s){
        testService.testRedisForMsg(s);
        return "完成";
    }

Service：

@Service
public class TestService {

    @Autowired
    private JedisPool jedisPool;

    @Autowired
    private UserMapper userMapper;

    

    public void testRedisForMsg(String msg){
        Jedis jedis = jedisPool.getResource();
        try{
            jedis.publish("redisChatTest", msg);
        }catch (Exception e){
            System.out.println("发布出错："+e.toString());
        }finally {
            if(jedis!=null){
                jedis.close();
            }
        }
    }



}

jedispool配置就不解释了。差不多就是这样，在浏览器访问触发redis发布的时候，本例的响应是在控制台输出发布信息。

输出信息：

channel:redisChatTestreceives message :lvelvelve

相应可以自己决定，感觉又学到了好玩的东西。