Camel将String发送到JMS队列，但检索字节数组

Question

I have a question related to Camel and JMS message.

My system contains a JMS topic and a JMS queue, say, TopicInput and QueueInput. A process of mine listens to QueueInput and process the message send into this queue. The result is then passed to another Topic, say, TopicOutput.

The process that processes the message uses Java and Apache Camel. The response my Camel route send out is a String. Therefore the String is sent to TopicOutput.

My problem is that when I send my message to the QueueInput directly, everything is fine, I get a String response from TopicOutput. However, if I send the request message to the TopicInput, which internally bridges to QueueInput anyway, the result I get from TopicOutput will be a byte array representation of the String.

Does anyone know how this could happen? I am not even sure whether this is the Camel's problem or JMS problem.

Any suggestions or hints will be helpful.

Many thanks.

Answer 1

Not quite sure what's going on exactly in your logic.

JMS has BytesMessage and TextMessage. To get a string directly, the message has to be TextMessage, otherwise a String must be constructed from a byte array, which you can retrieve from the message.

When sending messages using Camel, Camel tries to map the payload to the best JMS message type. Check this table out .

To be sure to always produce a TextMessage (that parses to String), convert the payload to String before sending it with a JMS producer. Make sure you are aware of what the message type and payload is in every step of your flow, then you should easily solve your issue.