Master RocketMQ: Core Concepts and Spring Boot Integration Guide

Environment: springboot2.3.9 + RocketMQ4.8.0

RocketMQ Architecture and Concepts

1. Message Model

2. Producer

3. Consumer

4. Topic

5. Broker Server

6. Name Server

7. Pull Consumer

8. Push Consumer

9. Producer Group

10. Consumer Group

11. Clustering Consumption

12. Broadcasting Consumption

13. Normal Ordered Message

14. Strictly Ordered Message

15. Message

16. Tag

RocketMQ consists of three core components: Producer (creates messages), Broker (stores and forwards messages), and Consumer (receives messages). Each Broker runs on a server and can host multiple Topics, which are divided into Message Queues. Consumers belong to ConsumerGroups, enabling load balancing and fault tolerance.

RocketMQ Service Setup

1. Download RocketMQ

2. Configure environment variables

3. Start Name Server

4. Start Broker

5. Send & receive messages via command line

Set environment variable:

C:\Users\MSI-NB>set NAMESRV_ADDR=localhost:9876

Send message:

C:\Users\MSI-NB>tools org.apache.rocketmq.example.quickstart.Producer

Receive message:

Spring Boot Integration with RocketMQ

Dependency:

<dependency>
  <groupId>org.apache.rocketmq</groupId>
  <artifactId>rocketmq-spring-boot-starter</artifactId>
  <version>2.2.0</version>
</dependency>

Configuration (application.yml):

rocketmq:
  nameServer: localhost:9876
  producer:
    group: demo-mq

Producer service:

@Service
public class ProducerService {

    @Resource
    private RocketMQTemplate rocketMQTemplate ;

    public void send(String message) {
        rocketMQTemplate.convertAndSend("test-topic", message);
    }

}

Consumer listener:

@RocketMQMessageListener(topic = "test-topic", consumerGroup = "consumer01-group")
@Component
public class ConsumerListener implements RocketMQListener<String> {

    @Override
    public void onMessage(String message) {
        System.out.println("Received message: " + message);
    }

}

REST controller to trigger sending:

@RestController
@RequestMapping("/messages")
public class MessageController {

    @Resource
    private ProducerService ps ;

    @GetMapping("")
    public Object send(String message) {
        ps.send(message) ;
        return "send success" ;
    }

}

Sending messages with specific tags:

rocketMQTemplate.convertAndSend("test-topic:tag1", message);

Receiving messages with tag filter:

@RocketMQMessageListener(topic = "test-topic", consumerGroup = "consumer01-group", selectorExpression = "tag1")

The selectorExpression defaults to "*"; specifying "tag1" ensures only messages with that tag are consumed. The topic and tag are separated by a colon, and the tag is the second element of the split array.