Redis事件通知示例

1. redis如同zk一样,提供了事件监听(或者说是回调机制), 下面是redis的配置说明:

############################# EVENT NOTIFICATION ##############################

# Redis can notify Pub/Sub clients about events happening in the key space.
# This feature is documented at http://redis.io/topics/notifications
#
# For instance if keyspace events notification is enabled, and a client
# performs a DEL operation on key "foo" stored in the Database 0, two
# messages will be published via Pub/Sub:
#
# PUBLISH __keyspace@0__:foo del
# PUBLISH __keyevent@0__:del foo
#
# It is possible to select the events that Redis will notify among a set
# of classes. Every class is identified by a single character:
#
# K Keyspace events, published with __keyspace@<db>__ prefix.
# E Keyevent events, published with __keyevent@<db>__ prefix.
# g Generic commands (non-type specific) like DEL, EXPIRE, RENAME, ...
# $ String commands
# l List commands
# s Set commands
# h Hash commands
# z Sorted set commands
# x Expired events (events generated every time a key expires)
# e Evicted events (events generated when a key is evicted for maxmemory)
# A Alias for g$lshzxe, so that the "AKE" string means all the events.
#
# The "notify-keyspace-events" takes as argument a string that is composed
# of zero or multiple characters. The empty string means that notifications
# are disabled.
#
# Example: to enable list and generic events, from the point of view of the
# event name, use:
#
# notify-keyspace-events Elg
#
# Example 2: to get the stream of the expired keys subscribing to channel
# name __keyevent@0__:expired use:
#
# 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" // 本示例做个key ttl通知

上面就是redis提供的事件通知类型,咱们可以*组合,官方也提供了两个事件组合示例。

下面是网上找一段说明,可以参考:

Redis事件通知示例

2. 测试

下面使用spingboot集成redis做个测试,如果一切正常,应该是key过期时,客户端 收到通知

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.1.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>qinfeng.zheng</groupId>
<artifactId>redis</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>redis</name>
<description>Demo project for Spring Boot</description> <properties>
<java.version>1.8</java.version>
</properties> <dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency> <dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies> <build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build> </project>
@SpringBootConfiguration
public class RedisConfig {
@Bean
RedisMessageListenerContainer container(RedisConnectionFactory connectionFactory) {
System.out.println("springboot2 redis 默认连接工厂:" + connectionFactory.getClass());
RedisMessageListenerContainer container = new RedisMessageListenerContainer();
container.setConnectionFactory(connectionFactory);
return container;
} }
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 RedisCallBack extends KeyExpirationEventMessageListener { public RedisCallBack(RedisMessageListenerContainer listenerContainer) {
super(listenerContainer);
} /**
* 针对redis key ttl数据处理(回调)
*
* @param message
* @param pattern
*/
@Override
public void onMessage(Message message, byte[] pattern) {
System.out.println("过期key:"+message.toString());
}
}
spring.redis.host=192.168.79.221
spring.redis.port=6379
spring.redis.password=123456
spring.redis.database=0

启动springboot即可

Redis事件通知示例

Redis事件通知示例

验证成功!

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