Let’s Spring Boot the RabbitMQ. We’ll create a producer and consumer communicating via default exchange and messages being routed to a single queue according to the routing key.

Configuring Maven: pom.xml

1. Create a Spring Boot project.
2. Use spring-boot-starter-amqp dependency.

3. Add javax.el as a support dependency for Spring AMQP.

   4.0.0 sk.upjs.ics.novotnyr spring-boot-amqp-demo 0.0.1-SNAPSHOT

   <parent>
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-starter-parent</artifactId>
       <version>1.2.4.RELEASE</version>
   </parent>
   
   <dependencies>
       <dependency>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-starter-amqp</artifactId>
       </dependency>
       <dependency>
           <groupId>org.glassfish</groupId>
           <artifactId>javax.el</artifactId>
           <version>3.0.0</version>
           <scope>runtime</scope>
       </dependency>
   </dependencies>
   

Producer

AMQP starter for Spring Boot enables the following features:

• preconfigured RabbitTemplate
• preconfigured CachingConnectionFactory
• preconfigured AmqpAdmin

In the following code, a message is sent to the default exchange with demo routing key. Essentially, this will route the message to the demo queue that may be created in the client.

@Configuration
@SpringBootApplication
public class AmpqApplicationContext implements CommandLineRunner {
    private static final Logger logger = LoggerFactory.getLogger(AmpqApplicationContext.class);

    @Autowired
    private RabbitTemplate rabbitTemplate;

    @Override
    public void run(String... strings) throws Exception {
        ScheduledExecutorService scheduledExecutorService = Executors.newScheduledThreadPool(1);
        Runnable task = new Runnable() {
            @Override
            public void run() {
                logger.info("Sending an event...");

                rabbitTemplate.convertAndSend("demo", "Hello World");
            }
        };
        scheduledExecutorService.scheduleAtFixedRate(task, 0, 2, TimeUnit.SECONDS);
    }

    public static void main(String[] args) {
        SpringApplication.run(AmpqApplicationContext.class, args);
    }
}

Consumer

The consumer declares a queue named demo.

@Configuration
@SpringBootApplication
public class AmqpClientApplicationContext {
    private static final Logger logger = LoggerFactory.getLogger(AmqpClientApplicationContext.class);

    @Bean
    public org.springframework.amqp.core.Queue demoQueue() {
        return new Queue("demo");
    }

    public static void main(String[] args) {
        SpringApplication.run(AmqpClientApplicationContext.class, args);
    }
}

The actual listener is declared as a separate Spring @Component. Beside that, a listening method is annotated via @RabbitListener that will process the received messages.

@Component
public class Listener {
    @RabbitListener(queues = "demo")
    public void onMessage(String data) {
        logger.info(data);
    }
}