Spring AMQP: bug with annotation triggered listener endpoints
I'm trying to set up a simple Spring AMQP script, but I get the following error:
Could not resolve method parameter at index 0 in method:
public void handleMessage(HelloMessage),
with 1 error(s): [Error in object 'msg': codes []; arguments [];
default message [@Payload param is required]]
I don't understand the error message, I was impressed, I can use any POJO to send and receive a message as per the documentation here .
This is a very simple setup:
Main
public class Program {
private static ConfigurableApplicationContext applicationContext;
public static void main(String[] args) {
try {
startApp();
System.out.println("Running...");
System.in.read();
applicationContext.close();
System.out.println("Shutting down...");
}
catch (Throwable e) {
e.printStackTrace();
}
}
private static void startApp() {
applicationContext = new ClassPathXmlApplicationContext("/application-context.xml");
applicationContext.refresh();
MessageSender messageSender = applicationContext.getBean(MessageSender.class);
messageSender.sendMessage("hello", 1);
}
context.xml applications
<context:component-scan base-package="org.abiri.amqpTest" />
<rabbit:connection-factory id="connectionFactory"
host="localhost" port="5672"
username="guest" password="guest"/>
<rabbit:template id="amqpTemplate" connection-factory="connectionFactory"/>
<rabbit:admin connection-factory="connectionFactory"/>
<rabbit:queue name="hello"/>
<bean id="rabbitListenerContainerFactory"
class="org.springframework.amqp.rabbit.config.SimpleRabbitListenerContainerFactory">
<property name="connectionFactory" ref="connectionFactory"/>
<property name="concurrentConsumers" value="3"/>
<property name="maxConcurrentConsumers" value="10"/>
</bean>
<rabbit:annotation-driven container-factory="rabbitListenerContainerFactory"/>
<rabbit:listener-container connection-factory="connectionFactory" />
MessageSender
@Service
public class MessageSender {
@Autowired
private AmqpTemplate amqpTemplate;
// Accessors...
public void sendMessage(String message, Integer sillyNumber) {
amqpTemplate.convertAndSend("hello",
new HelloMessage(message, sillyNumber));
}
}
MessageListener
@Component
public class MessageListener {
@RabbitListener(queues = "hello")
public void handleMessage(HelloMessage msg) {
out.println(format("Received message: %s with silly number: %d",
msg.getMessage(), msg.getSillyNumber()));
}
}
HelloMessage
public class HelloMessage {
private String message;
private Integer sillyNumber;
// Empty constructor, full constructor and accessors
}
I can verify that the message is indeed sent and is in the queue:
Default RabbitMQ installation via homebrew.
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Your problem is very simple!
To send any Java object through RabbitMQ with a default SimpleMessageConverter
, you must mark your class as Serializable
:
public class HelloMessage implements Serializable {
....
}
Of course, an application listener
must have the same class in its CLASSPATH in order to be able deserialize
byte[]
from payload
(AMQP message body) to the appropriate object HelloMessage
.
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