Message conversion after retrieving it from activemq topic

Question

I wanted to implement messaging between microservices using ActiveMQ as a broker, but after setting everyting as should be, one thing got me stuck. Before I describe the problem, here is I am approaching messaging:

Producer config:

@Slf4j
@Configuration
@EnableJms
public class JmsConfig {

  public static final String EBAY_TOPIC = "ebay.topic";

  @Bean
  public ActiveMQTopic destinationTopic() {

    return new ActiveMQTopic(EBAY_TOPIC);
  }

  @Bean
  public JmsListenerContainerFactory<?> connectionFactory(ConnectionFactory connectionFactory,
                                                          DefaultJmsListenerContainerFactoryConfigurer configurer) {
    DefaultJmsListenerContainerFactory factory = new DefaultJmsListenerContainerFactory();
    configurer.configure(factory, connectionFactory);
    factory.setPubSubDomain(true);
    return factory;
  }

  @Bean
  public MessageConverter jacksonJmsMessageConverter() {
    MappingJackson2MessageConverter converter = new MappingJackson2MessageConverter();
    converter.setTargetType(MessageType.TEXT);
    converter.setTypeIdPropertyName("_type");
    return converter;
  }

  @Bean
  public JmsTemplate jmsTemplate(ConnectionFactory connectionFactory, MessageConverter messageConverter) {
    JmsTemplate jmsTemplate = new JmsTemplate(connectionFactory);
    jmsTemplate.setDefaultDestinationName(EBAY_TOPIC);
    jmsTemplate.setConnectionFactory(connectionFactory);
    jmsTemplate.setMessageConverter(messageConverter);
    jmsTemplate.setPubSubDomain(true);
    return jmsTemplate;
  }
}

Producer sending message:

@RequiredArgsConstructor
@Slf4j
@RestController
@RequestMapping("/message")
public class IntercommunicationController {

  private final JmsTemplate jmsTemplate;

  @PostMapping("/send")
  public void sendMessageToOtherService(@RequestBody Message message) {
    jmsTemplate.convertAndSend(JmsConfig.EBAY_TOPIC, message);
  }
}

Receiver config:

@Configuration
@EnableJms
public class JmsConfig {

  public static final String EBAY_TOPIC = "ebay.topic";

  @Bean
  public JmsListenerContainerFactory<?> connectionFactory(ConnectionFactory connectionFactory,
                                                          DefaultJmsListenerContainerFactoryConfigurer configurer,
                                                          ErrorHandler errorHandler) {
    DefaultJmsListenerContainerFactory factory = new DefaultJmsListenerContainerFactory();
    configurer.configure(factory, connectionFactory);
    factory.setErrorHandler(errorHandler);
    factory.setPubSubDomain(true);
    return factory;
  }

  @Bean
  public MessageConverter jacksonJmsMessageConverter() {
    MappingJackson2MessageConverter converter = new MappingJackson2MessageConverter();
    converter.setTargetType(MessageType.TEXT);
    converter.setTypeIdPropertyName("_type");
    return converter;
  }
}

Receiver implementation:

@Slf4j
@Component
public class MessageListener {

  @JmsListener(destination = JmsConfig.EBAY_TOPIC, containerFactory = "connectionFactory")
  public void receiveMessage(@Payload Message receivedMessage) {
    log.info("Got message saying {}", receivedMessage);
  }
}

POJO which is being sent:

@NoArgsConstructor
@Data
public class Message {
  String content;
  String from;
}

Problem:

I'm getting error once I try to POST object through json and send it on topic. Once message get to the topic, the consumer can't handle deserialization of the message as in TypeIdPropertyName is different package path of the object which I'm sending to the one I'm trying to receive, they are 1:1 in both applications, but I'm getting:

2018-03-20 16:32:08.601 ERROR 1568 --- [enerContainer-1] c.g.g.s.c.config.MessageErrorHandler     : Listener method 'public void com.gft.graduate2018.sabb.client.listener.MessageListener.receiveMessage(client.domain.Message)' threw exception; nested exception is org.springframework.jms.support.converter.MessageConversionException: Failed to resolve type id [backend.model.dtos.Message]; nested exception is java.lang.ClassNotFoundException: backend.model.dtos.Message

What's the proper way of addressing that problem ? I could end up writing custom parser from string to object but probably that would not be the best solution. Hopefully there is someone who dealt with it before and can help resolve that problem :)

score 1 · Answer 1 · answered Mar 20 '18 at 18:42

See...

/**
 * Specify mappings from type ids to Java classes, if desired.
 * This allows for synthetic ids in the type id message property,
 * instead of transferring Java class names.
 * <p>Default is no custom mappings, i.e. transferring raw Java class names.
 * @param typeIdMappings a Map with type id values as keys and Java classes as values
 */
public void setTypeIdMappings(Map<String, Class<?>> typeIdMappings) {
     ...
}

...on the converter.

Set the mappings on both sides, so the __type header just contains a token that's mapped from the class name on the sending side and to the class name on the receiving side.

Message conversion after retrieving it from activemq topic

1 Answers1