redis之mq實現發佈訂閱模式

  • 2019 年 10 月 3 日
  • 筆記

概述

Redis不僅可作為緩存服務器,還可用作消息隊列,本示例演示如何使用redis實現發佈/訂閱消息隊列。

  • 在Redis中,發佈者沒有將消息發送給特定訂閱者的程序。相反,發佈的消息被描述為通道,而不知道(如果有的話)可能有哪些訂閱者。
  • 訂閱者表示對一個或多個主題感興趣,只接收感興趣的消息,而不知道(如果有的話)發佈者是什麼。
  • 發佈者和訂閱者的這種解耦可以實現更大的可伸縮性和更動態的網絡拓撲。

代碼實現

redis實現mq的存儲方式很多,可以使用list,zset及stream,這些數據的存儲結構決定了怎麼消費問題(消息是一次使用、允許多次使用、允許多端消息等),比如使用list,我們可以使用leftPush插入消息,使用rightPop消費消息,實現一條消息一次消息,可以參考與以示例代碼:

    @Test      public void testMq() {          for (int i = 0; i < 10; i++) {              redisTemplate.opsForList().leftPush("task-queue", "data" + i);              log.info("插入了一個新的任務==>{}", "data" + i);          }          String taskId = redisTemplate.opsForList().rightPop("task-queue").toString();          log.info("處理成功,清除任務==>{}", taskId);      }

1.配置代碼RedisConfig.java

package demo.data.mqRedis.config;    import org.springframework.beans.factory.annotation.Autowired;  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.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.listener.adapter.MessageListenerAdapter;  import org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer;  import org.springframework.data.redis.serializer.StringRedisSerializer;    @Configuration  @EnableCaching  public class RedisConfig extends CachingConfigurerSupport {        @Autowired      private RedisTemplate redisTemplate;        /**       * redisTemplate 序列化使用的jdkSerializeable, 存儲二進制位元組碼, 所以自定義序列化類,方便調試redis       *       * @param redisConnectionFactory       * @return       */      @Bean      public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory) {            RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();            //使用Jackson2JsonRedisSerializer來序列化和反序列化redis的value值          redisTemplate.setValueSerializer(new GenericJackson2JsonRedisSerializer());          redisTemplate.setHashValueSerializer(new GenericJackson2JsonRedisSerializer());            //使用StringRedisSerializer來序列化和反序列化redis的ke          redisTemplate.setKeySerializer(new StringRedisSerializer());          redisTemplate.setHashKeySerializer(new StringRedisSerializer());            //開啟事務          redisTemplate.setEnableTransactionSupport(true);            redisTemplate.setConnectionFactory(redisConnectionFactory);            return redisTemplate;      }        @Bean      MessageListenerAdapter messageListener() {          return new MessageListenerAdapter(new RedisMessageSubscriber());      }        @Bean      RedisMessageListenerContainer container(RedisConnectionFactory connectionFactory,                                              MessageListenerAdapter listenerAdapter) {            RedisMessageListenerContainer container = new RedisMessageListenerContainer();          container.setConnectionFactory(connectionFactory);          container.addMessageListener(listenerAdapter, topic());            return container;      }        @Bean      MessagePublisher redisPublisher() {          return new RedisMessagePublisher(redisTemplate, topic());      }        @Bean      ChannelTopic topic() {          return new ChannelTopic("messageQueue");      }  }  

2.定義消息發佈接口MessagePublisher.java

package demo.data.mqRedis.config;    public interface MessagePublisher {      void publish(String message);  }

3.發佈方實現RedisMessagePublisher.java

package demo.data.mqRedis.config;    import org.springframework.beans.factory.annotation.Autowired;  import org.springframework.data.redis.core.RedisTemplate;  import org.springframework.data.redis.listener.ChannelTopic;    /**   * 消息發佈方   */  public class RedisMessagePublisher implements MessagePublisher {        @Autowired      private RedisTemplate<String, Object> redisTemplate;        @Autowired      private ChannelTopic topic;        public RedisMessagePublisher(              RedisTemplate<String, Object> redisTemplate, ChannelTopic topic) {          this.redisTemplate = redisTemplate;          this.topic = topic;      }        public void publish(String message) {          redisTemplate.convertAndSend(topic.getTopic(), message);      }  }

4.消息接收方RedisMessageSubscriber.java

package demo.data.mqRedis.config;    import lombok.extern.slf4j.Slf4j;  import org.springframework.data.redis.connection.Message;  import org.springframework.data.redis.connection.MessageListener;  import org.springframework.stereotype.Service;    import java.util.ArrayList;  import java.util.List;    /**   * 消息訂閱方   */  @Service  @Slf4j  public class RedisMessageSubscriber implements MessageListener {        public static List<String> messageList = new ArrayList<>();        public void onMessage(Message message, byte[] pattern) {          messageList.add(message.toString());          log.info("訂閱方接收到了消息==>{}", message.toString());      }  }

5.最後貼上application.yml配置

spring:    redis:      host: 127.0.0.1      port: 6379      password:

查看運行結果

1.編寫測試用例試發佈消息TestRedisMQ.java

package demo.data.mqRedis;    import demo.data.mqRedis.config.RedisMessagePublisher;  import lombok.extern.slf4j.Slf4j;  import org.junit.Test;  import org.junit.runner.RunWith;  import org.springframework.beans.factory.annotation.Autowired;  import org.springframework.boot.test.context.SpringBootTest;  import org.springframework.test.context.junit4.SpringRunner;    import java.util.UUID;    @RunWith(SpringRunner.class)  @SpringBootTest  @Slf4j  public class TestRedisMQ {        @Autowired      RedisMessagePublisher redisMessagePublisher;        @Test      public void testMq() {          String message = "Message " + UUID.randomUUID();          redisMessagePublisher.publish(message);      }  }

2.運行結果

2019-09-05 15:51:33.931  INFO 10772 --- [    container-2] d.d.m.config.RedisMessageSubscriber      : 訂閱方接收到了消息==>"Message c95959bf-6c30-4801-bc80-0e1e3c9f81bc"

訂閱方成功接收到消息了

資料