将 Json 对象序列化为 Spring 的 Rabbit Listener 中的 Java 对象会引发异常

Question

I want to listen for messages coming into Rabbit queue with Spring's rabbit listener. My class looks very basic like this:

    @Component
public class MailMessageRabbitListener {
    private MailRepository mailRepository;
    private MailService mailService;

    @Autowired
    public MailMessageRabbitListener(MailRepository mailRepository, MailService mailService) {
        this.mailRepository = mailRepository;
        this.mailService = mailService;
    }

    @Bean
    public MessageConverter messageConverter() {
        return new Jackson2JsonMessageConverter();
    }

    @RabbitListener(queues = "msmail.queue")
    public void receiveMailMessage(JsonMailMessage jsonMailMessage) throws Exception {
        System.out.println(jsonMailMessage);
    }
}

My mapping class JsonMailMessage looks like this:

@Data
@NoArgsConstructor
@RequiredArgsConstructor
public class JsonMailMessage {
    @NonNull
    private String userToken;
    @NonNull
    private String sendTo;
    @NonNull
    private String subject;
    @NonNull
    private String content;
    @NonNull
    private String[] files;

}

Now I'm able to successfully listen to a queue, the problem is when I send message such as this within Rabbit queue:

Json array is filled with base64 encoded files, which should be basic String expressions, so the Jackson2JsonMessageConverter should be able to convert the files.

I'm however getting this kind of exception:

Bean [---------messaging.MailMessageRabbitListener@35ff072c]
    at org.springframework.amqp.rabbit.listener.adapter.MessagingMessageListenerAdapter.invokeHandler(MessagingMessageListenerAdapter.java:185) ~[spring-rabbit-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.amqp.rabbit.listener.adapter.MessagingMessageListenerAdapter.onMessage(MessagingMessageListenerAdapter.java:120) ~[spring-rabbit-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.doInvokeListener(AbstractMessageListenerContainer.java:1414) ~[spring-rabbit-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.actualInvokeListener(AbstractMessageListenerContainer.java:1337) ~[spring-rabbit-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.invokeListener(AbstractMessageListenerContainer.java:1324) ~[spring-rabbit-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.executeListener(AbstractMessageListenerContainer.java:1303) ~[spring-rabbit-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.doReceiveAndExecute(SimpleMessageListenerContainer.java:785) [spring-rabbit-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.receiveAndExecute(SimpleMessageListenerContainer.java:769) [spring-rabbit-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.access$700(SimpleMessageListenerContainer.java:77) [spring-rabbit-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer$AsyncMessageProcessingConsumer.run(SimpleMessageListenerContainer.java:1010) [spring-rabbit-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at java.lang.Thread.run(Thread.java:748) [na:1.8.0_171]
Caused by: org.springframework.messaging.converter.MessageConversionException: Cannot convert from [[B] to [-----dto.JsonMailMessage] for GenericMessage [payload=byte[118], headers={amqp_receivedDeliveryMode=NON_PERSISTENT, amqp_receivedRoutingKey=msmail.queue, amqp_deliveryTag=1, amqp_consumerQueue=msmail.queue, amqp_redelivered=false, id=b997e8cb-3424-df90-5370-aa4cf79175be, amqp_consumerTag=amq.ctag-lL9Y6R67fJc6DyCHAiWQRA, Content-Type=application/json, timestamp=1538554985476}]
    at org.springframework.messaging.handler.annotation.support.PayloadArgumentResolver.resolveArgument(PayloadArgumentResolver.java:144) ~[spring-messaging-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.messaging.handler.invocation.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:116) ~[spring-messaging-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.messaging.handler.invocation.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:137) ~[spring-messaging-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.messaging.handler.invocation.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:109) ~[spring-messaging-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.amqp.rabbit.listener.adapter.HandlerAdapter.invoke(HandlerAdapter.java:51) ~[spring-rabbit-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.amqp.rabbit.listener.adapter.MessagingMessageListenerAdapter.invokeHandler(MessagingMessageListenerAdapter.java:182) ~[spring-rabbit-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    ... 10 common frames omitted

Update

It's working, the message is getting converted to Java object. The problem starts when I want to return the object directly from Listener method.

 @RabbitListener(queues = "msmail.queue")
public JsonMailMessage receiveMailMessage(JsonMailMessage jsonMailMessage){
  return jsonMailMessage;
}

It throws different exception:

Caused by: org.springframework.amqp.AmqpException: Cannot determine ReplyTo message property value: Request message does not contain reply-to property, and no default response Exchange was set.
    at org.springframework.amqp.rabbit.listener.adapter.AbstractAdaptableMessageListener.getReplyToAddress(AbstractAdaptableMessageListener.java:398) ~[spring-rabbit-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.amqp.rabbit.listener.adapter.AbstractAdaptableMessageListener.handleResult(AbstractAdaptableMessageListener.java:307) ~[spring-rabbit-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    ... 10 common frames omitte

Answer 1

The content_type is a well-known property not and arbitrary header; add it to Properties: instead.

Click the ? in the UI to see the well-known properties.

Since there is no content type, the converter simply returns the byte[] unchanged.

Answer 2

Remove the MessageConverter Bean and try.

I also faced the same problem, after removing MessageConverter Bean, it works fine.