Redis拓展之定时消息通知实现详解

1. Redis实现定时消息通知

简单定时任务通知: 利用redis的keyspace notifications(即:键过期后事件通知机制)

开启方法

修改server.conf文件，找到notify-keyspace-events , 修改为“Ex”
使用cli命令: redis-cli config set notify-keyspace-events Ex

redis 配置参考

2. 例子

创建springboot项目

修改pom.xml 和 yml

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>2.6.9</version> <!– 这个版本其实还是挺重要的，如果是2.7.3版本的话，大概会无法成功自动装载 RedisConnectionFactory –>
<relativePath/> <!– lookup parent from repository –>
</parent>
<groupId>cn.lazyfennec</groupId>
<artifactId>redisdemo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>redisdemo</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.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<configuration>
<excludes>
<exclude>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</exclude>
</excludes>
</configuration>
</plugin>
</plugins>
</build>
</project>

application.yml

spring:
redis:
database: 0
host: 192.168.1.7
port: 6379
jedis:
pool:
max-active: 8
max-idle: 8
min-idle: 0
max-wait: 1

创建RedisConfig

package cn.lazyfennec.redisdemo.config;
import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
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.connection.jedis.JedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.RedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;
/**
* @Author: Neco
* @Description:
* @Date: create in 2022/9/20 23:19
*/
@Configuration
@EnableCaching
public class RedisConfig {
@Bean
public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory) {
// 设置序列化
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);
// 配置redisTemplate
RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();
redisTemplate.setConnectionFactory(redisConnectionFactory);
RedisSerializer stringSerializer = new StringRedisSerializer();
redisTemplate.setKeySerializer(stringSerializer); // key 序列化
redisTemplate.setValueSerializer(jackson2JsonRedisSerializer); // value 序列化
redisTemplate.setHashKeySerializer(stringSerializer); // Hash key 序列化
redisTemplate.setHashValueSerializer(jackson2JsonRedisSerializer); // Hash value 序列化
redisTemplate.afterPropertiesSet();
return redisTemplate;
}
}

创建RedisListenerConfiguration

package cn.lazyfennec.redisdemo.config;
import org.springframework.beans.factory.annotation.Autowired;
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;
/**
* @Author: Neco
* @Description:
* @Date: create in 2022/9/21 11:02
*/
@Configuration
public class RedisListenerConfiguration {
@Autowired
private RedisConnectionFactory factory;
@Bean
public RedisMessageListenerContainer redisMessageListenerContainer() {
RedisMessageListenerContainer redisMessageListenerContainer = new RedisMessageListenerContainer();
redisMessageListenerContainer.setConnectionFactory(factory);
return redisMessageListenerContainer;
}
}

事件监听事件 RedisTask

package cn.lazyfennec.redisdemo.task;
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;
import java.nio.charset.StandardCharsets;
/**
* @Author: Neco
* @Description:
* @Date: create in 2022/9/21 11:05
*/
@Component
public class RedisTask extends KeyExpirationEventMessageListener {
public RedisTask(RedisMessageListenerContainer listenerContainer) {
super(listenerContainer);
}
@Override
public void onMessage(Message message, byte[] pattern) {
// 接收到事件后回调
String channel = new String(message.getChannel(), StandardCharsets.UTF_8);
String key = new String(message.getBody(), StandardCharsets.UTF_8);
System.out.println(\”key:\” + key + \”, channel:\” + channel);
}
}

发布 RedisPublisher

package cn.lazyfennec.redisdemo.publisher;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;
import java.util.Random;
import java.util.concurrent.TimeUnit;
/**
* @Author: Neco
* @Description:
* @Date: create in 2022/9/21 16:34
*/
@Component
public class RedisPublisher {
@Autowired
RedisTemplate<String, Object> redisTemplate;
// 发布
public void publish(String key) {
redisTemplate.opsForValue().set(key, new Random().nextInt(200), 10, TimeUnit.SECONDS);
}
// 循环指定时间触发
@Scheduled(cron = \”0/15 * * * * ?\”)
public void scheduledPublish() {
System.out.println(\”scheduledPublish\”);
redisTemplate.opsForValue().set(\”str1\”, new Random().nextInt(200), 10, TimeUnit.SECONDS);
}
}

要实现Scheduled需要在启动类上加上注解

@SpringBootApplication
@EnableScheduling // 要加上这个，用以启动
public class RedisdemoApplication {

修改TestController

package cn.lazyfennec.redisdemo.controller;
import cn.lazyfennec.redisdemo.publisher.RedisPublisher;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
/**
* @Author: Neco
* @Description:
* @Date: create in 2022/9/21 16:32
*/
@RestController
public class TestController {
@Autowired
RedisPublisher redisPublisher;
@GetMapping(\”/redis/{key}\”)
public String publishEvent(@PathVariable String key) {
// 发布事件
redisPublisher.publish(key);
return \”OK\”;
}
}