RocketMQ集成Springboot --Chapter3

RocketMQ实现顺序消息

实际开发中如果没有顺序消费的必要需求，不建议使用顺序消费，顺序消费是单线程的效率比较低。

代码示例

-------生产者
生产者主要设置队列选择器在里面写选择队列的逻辑，通过取模进行选取， rocketMQTemplate.sendOneWayOrderly(“orderlyTopicBoot”,msg,String.valueOf(step.getOrderId()));

    /**
     *生产者代码
     * 顺序消费
     */
    @Test
    public void sendOlderlyMsg(){
        //设置队列选择器
        rocketMQTemplate.setMessageQueueSelector(new MessageQueueSelector() {
            @Override
            public MessageQueue select(List<MessageQueue> list, org.apache.rocketmq.common.message.Message message, Object o) {
                String orderIdStr = (String) o;
                long orderId = Long.parseLong(orderIdStr);
                int index = (int) (orderId % list.size());
                return list.get(index);
            }
        });
        List<OrderStep> orderSteps = OrderUtil.buildOrders();
        for (OrderStep step : orderSteps) {
            Message<String> msg = MessageBuilder.withPayload(step.toString()).build();
            rocketMQTemplate.sendOneWayOrderly("orderlyTopicBoot",msg,String.valueOf(step.getOrderId()));
        }
    }

-------消费者
只需要在@RocketMQMessageListener注解中指定一下消费模式为顺序消费即可开启单线程消费consumeMode = ConsumeMode.ORDERLY

    /**
     *
     * 顺序消费
     */
@Component
@RocketMQMessageListener(consumerGroup = "olderConsumerBoot",topic = "orderlyTopicBoot",consumeMode = ConsumeMode.ORDERLY)
public class OlderlyTopicListener implements RocketMQListener<MessageExt> {
    @Override
    public void onMessage(MessageExt messageExt) {
        System.out.println("当前线程："+Thread.currentThread()+"队列ID:"+messageExt.getQueueId()+",消息内容："+new String(messageExt.getBody(), Charset.defaultCharset()));

    }
}