redis过期时间是0秒 redis过期触发事件_redis



redis默认关闭，不建议开启。本文提供参考。键空间通知通常是不启用的，因为这个过程会产生额外消耗。



1、开启redis配置

#
#  notify-keyspace-events Ex
#
#  By default all notifications are disabled because most users don't need
#  this feature and the feature has some overhead. Note that if you don't
#  specify at least one of K or E, no events will be delivered.
notify-keyspace-events "Ex"

字符

发送通知

K

键空间通知，所有通知以 keyspace@ 为前缀，针对Key

E

键事件通知，所有通知以 keyevent@ 为前缀，针对event

g

DEL 、 EXPIRE 、 RENAME 等类型无关的通用命令的通知

$

字符串命令的通知

l

列表命令的通知

s

集合命令的通知

h

哈希命令的通知

z

有序集合命令的通知

x

过期事件：每当有过期键被删除时发送

e

驱逐(evict)事件：每当有键因为 maxmemory 政策而被删除时发送

A

参数 g$lshzxe 的别名，相当于是All

    输入的参数中至少要有一个 K 或者 E ， 否则的话， 不管其余的参数是什么， 都不会有任何通知被分发。上表中斜体的部分为通用的操作或者事件，而黑体则表示特定数据类型的操作。例如，“Kx”表示想监控某个Key的失效事件。



2、java实现



2.1 pom配置

    spring boot2的配置

<dependencies>
	<!-- spring boot -->
	<dependency>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-web</artifactId>
	</dependency>
	<!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-data-redis -->
	<dependency>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-data-redis</artifactId>
	</dependency>
	<!--spring2.0集成redis所需common-pool2 -->
	<dependency>
		<groupId>org.apache.commons</groupId>
		<artifactId>commons-pool2</artifactId>
	</dependency>
</dependencies>



2.2 配置

import java.lang.reflect.Method;

import javax.annotation.Resource;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.CacheManager;
import org.springframework.cache.annotation.CachingConfigurerSupport;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.cache.interceptor.KeyGenerator;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.cache.RedisCacheManager;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.listener.ChannelTopic;
import org.springframework.data.redis.listener.RedisMessageListenerContainer;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;

import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.spring.pro.constant.ChannelConstant;
import com.spring.pro.listener.KeyExpiredListener;
import com.spring.pro.listener.UserMsgListener;

/**
 * 缓存管理（注解用）
 * @ClassName: CacheService
 * @Description:
 * @author ybw
 * @date 2017年4月20日 下午5:44:52
 */
@Configuration
@EnableCaching // 启动缓存
public class CacheConfig extends CachingConfigurerSupport {

	/**
	 * 生成key的策略
	 * @return
	 */
	@Bean
	public KeyGenerator keyGenerator() {
		return new KeyGenerator() {
			@Override
			public Object generate(Object target, Method method, Object... params) {
				StringBuilder sb = new StringBuilder();
				sb.append(target.getClass().getName());
				sb.append(method.getName());
				for (Object obj : params) {
					sb.append(obj.toString());
				}
				return sb.toString();
			}
		};
	}

	/**
	 * 管理缓存
	 * @param redisTemplate
	 * @return
	 */
	@Bean
	public CacheManager cacheManager(RedisConnectionFactory redisConnectionFactory) {
		RedisCacheManager.RedisCacheManagerBuilder builder = RedisCacheManager.RedisCacheManagerBuilder
				.fromConnectionFactory(redisConnectionFactory);
		return builder.build();
	}

	/**
	 * RedisTemplate配置
	 * @param factory
	 * @return
	 */
	@Bean
	public RedisTemplate<String, String> redisTemplate(RedisConnectionFactory factory) {
		StringRedisTemplate template = new StringRedisTemplate(factory);
		// 使用Jackson库将对象序列化为JSON字符串
		Jackson2JsonRedisSerializer<Object> jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer<Object>(
				Object.class);
		ObjectMapper om = new ObjectMapper();
		om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
		om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
		jackson2JsonRedisSerializer.setObjectMapper(om);
		template.setValueSerializer(jackson2JsonRedisSerializer);
		template.afterPropertiesSet();
		return template;
	}

	// --------------------------pub/sub-----------------------------------------
	@Resource
	private KeyExpiredListener keyExpiredListener;

		
	@Bean
	public ChannelTopic expiredTopic() {
		return new ChannelTopic(ChannelConstant.expired);
	}

	@Bean
	public RedisMessageListenerContainer redisMessageListenerContainer(
			@Autowired RedisConnectionFactory redisConnectionFactory) {
		RedisMessageListenerContainer redisMessageListenerContainer = new RedisMessageListenerContainer();
		redisMessageListenerContainer.setConnectionFactory(redisConnectionFactory);
		redisMessageListenerContainer.addMessageListener(keyExpiredListener, expiredTopic());
		return redisMessageListenerContainer;
	}
	// --------------------------pub/sub end------------------------------------------
}



3、监听

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.connection.Message;
import org.springframework.data.redis.connection.MessageListener;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Component;

/**
 * @Title: KeyExpiredListener.java
 * @Package com.spring.pro.listener
 * @Description:
 * @author ybwei
 * @date 2018年8月13日 下午3:54:41
 * @version V1.0
 */
@Component
public class KeyExpiredListener implements MessageListener {

	private final static Logger LOG = LoggerFactory.getLogger(UserMsgListener.class);
	@Autowired
	private RedisTemplate<?, ?> redisTemplate;

	@Override
	public void onMessage(Message message, byte[] pattern) {
		System.out.println("onPMessage pattern " + pattern + " " + " " + message);
		String channel = new String(message.getChannel());
		String str = (String) redisTemplate.getValueSerializer().deserialize(message.getBody());
		LOG.info("received message channel {}, body is {}.", channel, str);
	}

}



4、测试

set aa bb
expire aa 2 #设置失效时间2秒

    aa失效后，即可得到通知。