简介

发布订阅（Pub/Sub）：目前广泛使用的通信模型，它采用事件作为基本的通信机制，提供大规模系统所要求的松散耦合的交互模式：订阅者(如客户端)以事件订阅的方式表达出它有兴趣接收的一个事件或一类事件；发布者(如服务器)可将订阅者感兴趣的事件随时通知相关订阅者------是不是与设计模式里面的观察者模式一个妈妈生的？

最经典的应用场景就是微博和公众号，任何粉丝只要关注（订阅）了某一个人的微博或者公众号，该微博或者公众号只有有状态更新，都会将消息推送（发布）到粉丝..

命令实现发布订阅

redis订阅 msg 频道

redis向msg频道发送消息

springboot整合发布订阅

导入依赖

<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-redis</artifactId></dependency>

Redis消息订阅配置类

@Configuration
public class RedisConfig {@BeanRedisMessageListenerContainer container (RedisConnectionFactory redisConnectionFactory, MessageListenerAdapter listenerAdapter){RedisMessageListenerContainer container = new RedisMessageListenerContainer();container.setConnectionFactory(redisConnectionFactory);// 可以添加多个 messageListener，配置不同的交换机container.addMessageListener(listenerAdapter,new PatternTopic("msg"));return  container;}//消息监听器适配器，绑定消息处理器，利用反射技术调用消息处理器的业务方法@BeanMessageListenerAdapter listenerAdapter(RedisReceiver  receiver) {return new MessageListenerAdapter(receiver, "receiveMessage");}@Beanpublic RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory) throws UnknownHostException {RedisTemplate<String, Object> template = new RedisTemplate();//连接工厂template.setConnectionFactory(redisConnectionFactory);//序列化配置Jackson2JsonRedisSerializer objectJackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);ObjectMapper objectMapper = new ObjectMapper();objectMapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);objectMapper.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);objectJackson2JsonRedisSerializer.setObjectMapper(objectMapper);StringRedisSerializer stringRedisSerializer = new StringRedisSerializer();//配置具体序列化//key采用string的序列化方式template.setKeySerializer(stringRedisSerializer);//hash的key采用string的序列化方式template.setHashKeySerializer(stringRedisSerializer);//value序列化采用jacksontemplate.setValueSerializer(objectJackson2JsonRedisSerializer);//hash的value序列化采用jacksontemplate.setHashValueSerializer(objectJackson2JsonRedisSerializer);template.afterPropertiesSet();return template;}}

消息监听类

@Component
public class RedisReceiver {public void receiveMessage(String message) {System.out.println("=====================>"+message);}}

测试接口

@Component
public class MessageSend {@Autowiredprivate RedisTemplate redisTemplate;@Scheduled(fixedRate = 2000)public void sendMessage(){redisTemplate.convertAndSend("msg",String.valueOf(Math.random()));}
}