RabbitMQ 与 Spring-AMQP 事务及消息限流机制详解

配置队列

@Configuration
public class RabbitMQConfig {
    @Bean("transQueue")
    public Queue transQueue() {
        return QueueBuilder.durable(Constants.TRANS_QUEUE).build();
    }
}

2. 消息限流

消息限流 (Flow Control) 是 RabbitMQ 防止生产者发送消息速度超过消费者处理能力，导致消息积压和系统崩溃的保护机制。

发送消息

@RestController
@RequestMapping("/producer")
public class ProducerController {
    @Resource(name = "rabbitTemplate")
    private RabbitTemplate rabbitTemplate;

    @RequestMapping("/qos")
    public String qos() {
        for (int i = 0; i < 20; i++) {
            rabbitTemplate.convertAndSend(Constants.QOS_EXCHANGE, "qos", "qos test:" + i);
        }
        return "发送成功";
    }
}

配置消费者

@Component
@Slf4j
public class QosListener {
    @RabbitListener(queues = Constants.QOS_QUEUE)
    public void handMessage(Message message, Channel channel) throws IOException {
        long deliveryTag = message.getMessageProperties().getDeliveryTag();
        try {
            log.info("接收到消息:{},deliveryTag:{}", new String(message.getBody(), StandardCharsets.UTF_8), deliveryTag);
            log.info("处理成功");
            // channel.basicAck(deliveryTag, true); // 消费者不确认消息
        } catch (Exception e) {
            channel.basicNack(deliveryTag, true, true);
        }
    }
}

限制每个消费者未确认的最大消息数

spring:
  rabbitmq:
    listener:
      simple:
        acknowledge-mode: manual # 消费者确认机制
        prefetch: 5

声明和配置交换器、队列和绑定关系

@Configuration
public class RabbitMQConfig {
    @Bean("qosQueue")
    public Queue qosQueue() {
        return QueueBuilder.durable(Constants.QOS_QUEUE).build();
    }

    @Bean("qosExchange")
    public DirectExchange qosExchange() {
        return ExchangeBuilder.directExchange(Constants.QOS_EXCHANGE).build();
    }

    @Bean("qosBinding")
    public Binding qosBinding(@Qualifier("qosExchange") DirectExchange directExchange,
                              @Qualifier("qosQueue") Queue queue) {
        return BindingBuilder.bind(queue).to(directExchange).with("qos");
    }
}