Redis拓展 - 实现定时消息通知-平芜编程栈

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"; } }

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