关于RocketMQ顺序消费的问题

Question

问题如下图所示，RocketMQ小白，希望能得到解答

 

Answer 1

关键就是Broker中还有多个MessageQueue，同一个MessageQueue中的消息才能顺序消费。

官网中，发送消息时，使用了一个MessageQueueSelector

发送端：

SendResult sendResult = defaultMQProducer.send(message, new MessageQueueSelector() {
    @Override
    public MessageQueue select(List<MessageQueue> mqs, Message msg, Object arg) {
        return mqs.get(0);
    }
},i);

消费端： 

@Bean(name = "pushConsumerOrderly", initMethod = "start",destroyMethod = "shutdown")
public DefaultMQPushConsumer pushConsumerOrderly() throws MQClientException {
    DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("pushConsumerOrderly");
    consumer.setNamesrvAddr("192.168.73.130:9876;192.168.73.131:9876;192.168.73.132:9876;");
    consumer.subscribe("broker-a-topic","*");
    consumer.registerMessageListener((MessageListenerConcurrently) (msgs, context) -> {
        Random random = new Random();
        try {
            Thread.sleep(random.nextInt(5) * 1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        for (MessageExt msg : msgs) {
            System.out.println(new String(msg.getBody()));
        }
        return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
    });
    return consumer;
}