Redis, expiration monitoring

Application scenarios, coupon expiration, monitoring

Configuration class

import org.springframework.cache.annotation.CachingConfigurerSupport;
import org.springframework.cache.annotation.EnableCaching;
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
@EnableCaching
public class RedisConfig  extends CachingConfigurerSupport {

    @Bean
    RedisMessageListenerContainer container(RedisConnectionFactory redisConnectionFactory) {
        RedisMessageListenerContainer container = new RedisMessageListenerContainer();
        container.setConnectionFactory(redisConnectionFactory);
        return container;
    }

}

Monitoring class

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.connection.Message;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.listener.KeyExpirationEventMessageListener;
import org.springframework.data.redis.listener.RedisMessageListenerContainer;
import org.springframework.stereotype.Component;

import java.util.concurrent.TimeUnit;

@Component
public class RedisListenerComponent extends KeyExpirationEventMessageListener {

    @Autowired
    private StringRedisTemplate stringRedisTemplate;

    private final String SET_NX = "setnx:";


    public RedisListenerComponent(RedisMessageListenerContainer listenerContainer) {
        super(listenerContainer);
    }
    @Override
    public void onMessage(Message message, byte[] pattern) {
        super.onMessage(message, pattern);
        String expiredKey = message.toString();
        //判定key的前缀,避免消费到自己
        if (!expiredKey.startsWith(SET_NX)){
            // 加锁操作,避免重复消费
            Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(SET_NX + expiredKey, String.valueOf(System.currentTimeMillis()),30, TimeUnit.SECONDS);
            if (flag){
                System.out.println(expiredKey);
                stringRedisTemplate.delete(SET_NX + expiredKey);
                System.out.println("删除锁...");
            }
        }
    }
}