SpringBoot listens to Redis key expiration callback

Scenes

Spring bootImplementing monitoring Redis keyfailure events can deal with certain scenarios, such as: processing order expiration and automatic cancellation, user membership expiration...

Enable Redis key expiration callback notification

RedisBy default, the key expiration monitoring function is not enabled, and it needs to be manually modified in the configuration file.

• Linuxoperating system
  • Modify the configuration file redisin the installation directory redis.conf, and then find notify-keyspace-events Exthis line of code, which is commented out by default, just uncomment it (that is, delete the # in front).
  • There is also a situation where there is no such line, in this case just add this line directly.
  • Then reboot redis.
• Windowsoperating system
  • redis.windows.confFind and two files in the installation directory redis.windows-service.conf, then modify the fields in these two files respectively notify-keyspace-events Ex, and uncomment them.
  • Then restart redis, Windowsthe restart command is redis-server.exe --service-start.

Java code implements monitoring callback

Add Redis key expiration monitoring configuration

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.listener.RedisMessageListenerContainer;

@Configuration
public class RedisListenerConfig {
    
    
   
   @Bean
   RedisMessageListenerContainer container(RedisConnectionFactory connectionFactory) {
    
    
       RedisMessageListenerContainer container = new RedisMessageListenerContainer();
       container.setConnectionFactory(connectionFactory);
       return container;
   }
   
}

Create a listener class

import org.springframework.data.redis.connection.Message;
import org.springframework.data.redis.listener.KeyExpirationEventMessageListener;
import org.springframework.data.redis.listener.RedisMessageListenerContainer;
import org.springframework.stereotype.Component;

@Component
public class KeyExpiredListener extends KeyExpirationEventMessageListener {
    
    

    public KeyExpiredListener(RedisMessageListenerContainer listenerContainer) {
    
    
        super(listenerContainer);
    }

    /**
     * 使用该方法监听，当Redis的key失效的时候执行该方法
     * @param message message must not be {@literal null}.
     * @param pattern pattern matching the channel (if specified) - can be {@literal null}.
     */
    @Override
    public void onMessage(Message message, byte[] pattern) {
    
    
        // 过期的Key
        String expiraKey = message.toString();
        System.out.println("该Key已失效："+expiraKey);
    }

}

The specified settingRedis value and its expiration timekey

Redis SetexThe command keysets . If keyalready exists, SETEXthe command will replace the old value.