Jedis实现Redis操作事件通知

「爱情、让人受尽委屈。」 2022-06-13 13:21 200阅读 0赞

Redis的Java客户端Jedis可以通过订阅/发布(Pub/Sub)机制，接收那些以某种方式改变了Redis数据空间的事件通知。  
Redis官网理论介绍地址：[https://redis.io/topics/notifications][https_redis.io_topics_notifications]

**实现步骤：**  
1.修改配置：键空间通知功能耗费CPU，默认关闭，需要修改配置文件redis.conf或 操作CONFIG SET命令，设置notify-keyspace-events选项，来启用或关闭该功能。  
2.对Redis实例进行发布订阅，指定监听类和监听事件类型；  
3.监听类继承JedisPubSub，实现相应操作；  
4.客户端进行操作，以触发订阅事件发生。

**下面为代码实现**  
1.判断修改配置、发布订阅类

import java.util.List;
    import redis.clients.jedis.Jedis;
    import redis.clients.jedis.JedisPool;
    import redis.clients.jedis.JedisPoolConfig;
    import redis.clients.jedis.JedisPubSub;
    
    public class Subscriber { 
    
        public static void main(String[] args) {
            JedisPool pool = new JedisPool(new JedisPoolConfig(), "192.168.44.53");
    
            Jedis jedis = pool.getResource();
            config(jedis);
    
            jedis.psubscribe(new KeyExpiredListener(), "__key*__:*");
        }
        private static void config(Jedis jedis){
            String parameter = "notify-keyspace-events";
            List<String> notify = jedis.configGet(parameter);
    
            if(notify.get(1).equals("")){
                jedis.configSet(parameter, "KEA");
            }
        }
    }
    class KeyExpiredListener extends JedisPubSub {
    
        @Override
        public void onPSubscribe(String pattern, int subscribedChannels) {
            System.out.println("onPSubscribe " + pattern + " " + subscribedChannels);
        }
    
        @Override
        public void onPMessage(String pattern, String channel, String message) {
    
            System.out.println("onPMessage pattern " + pattern + " " + channel + " " + message);
        }
    //add other Unimplemented methods
    }

2.测试类：

import redis.clients.jedis.Jedis;
    import redis.clients.jedis.JedisPool;
    import redis.clients.jedis.JedisPoolConfig;
    
    public class TestJedis { 
    
        public static void main(String[] args) {
            JedisPool pool = new JedisPool(new JedisPoolConfig(), "192.168.44.53");
    
            Jedis jedis = pool.getResource();
            jedis.set("notify", "umq");
            jedis.expire("notify", 10);
    
        }
    }

[https_redis.io_topics_notifications]: https://redis.io/topics/notifications