Redis发布订阅PUB/SUB

Redis发布订阅PUB/SUB是一种消息通信模式，发送者PUB发送消息，订阅者SUB接收消息。Redis客户端可以订阅任意数量的频道，一个通道CHANNEL可以被多个客户端订阅，当一条消息发送到CHANNEL中去后所有订阅的客户端都会接收到此消息。

一、Redis客户端命令

• 订阅一个或多个频道

SUBSCRIBE channel[channel ...] 

• 取消客户端对一个或多个频道的订阅

UNSUBSCRIBE [channel [channel ...]]

• 订阅一个或多个符合给定模式的频道

PSUBSCRIBE pattern [pattern ...]

• 取消一个或多个符合给定模式的频道的订阅

PUNSUBSCRIBE [pattern [pattern ...]]

• 向通道中发送消息

PUBLISH channel message

• 查询活跃channel列表

PUBSUB CHANNELS [pattern]

• 查询已订阅模式的数量

PUBSUB NUMPAT 

二、springboot发布订阅频道

• 定义Receiver实体类

public class Receiver {
    private static final Logger LOGGER = LoggerFactory.getLogger(Receiver.class);

    private AtomicInteger counter = new AtomicInteger();

    public void receiveMessage(String message) {
        LOGGER.info("Received <" + message + ">");
        counter.incrementAndGet();
    }

    public int getCount() {
        return counter.get();
    }
}

• 定义订阅消息通道配置类

@Configuration
public class RedisConfig {

    @Bean
    public String register(RedisMessageListenerContainer factory, MessageListenerAdapter messageListenerAdapter) {
        factory.addMessageListener(messageListenerAdapter, PatternTopic.of("test"));
        factory.addMessageListener(messageListenerAdapter, ChannelTopic.of("test1"));
        return "success";
    }

    @Bean
    public String register1(@Qualifier("test1RedisMessageListenerContainer") RedisMessageListenerContainer factory, MessageListenerAdapter messageListenerAdapter) {
        factory.addMessageListener(messageListenerAdapter, PatternTopic.of("test"));
        factory.addMessageListener(messageListenerAdapter, PatternTopic.of("test1"));
        return "success";
    }

    @Bean
    public MessageListenerAdapter messageListenerAdapter() {
        return new MessageListenerAdapter(new Receiver(), "receiveMessage");
    }
}

上述是基于自定义redis sdk，支持多个RedisMessageListenerContainer

• 向频道中发送消息

    @GetMapping("send")
    public void send() {
        RedisDbFactory.getStringRedisTemplate().convertAndSend("test", "测试消息");
        RedisDbFactory.getStringRedisTemplate("test1").convertAndSend("test1", "测试消息1");
    }

开源SDK：https://github.com/mingyang66/spring-parent