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javajacksonspring-messaging

Pushing my custom object data to a message queue using @sendto

I am using spring-messaging with websockets. Currently I have a @MessageMapping controller to get data from websocket client.

@MessageMapping("/path1")
@SendTo("/queue/path1-data")
public BrokerPacket myController(String message) throws Exception {

    return new BrokerPacket(message, "1234", "5677");
}

My BrokerPacket looks like:

public class BrokerPacket {

    private String data;
    private String value1;
    private String value2;

    public BrokerPacket(String data, String value1, String value2) {
        this.data = data;
        this.value1 = value1;
        this.value2 = value2;
    }
}

This gives me a MessageConversionException

org.springframework.messaging.converter.MessageConversionException: Unable to convert payload with type='com.company.dto.BrokerPacket', contentType='null', converter=[CompositeMessageConverter[converters=[org.springframework.messaging.converter.StringMessageConverter@2f9f7783, org.springframework.messaging.converter.ByteArrayMessageConverter@312048e, org.springframework.messaging.converter.MappingJackson2MessageConverter@7764e617]]]
    at org.springframework.messaging.core.AbstractMessageSendingTemplate.doConvert(AbstractMessageSendingTemplate.java:186) ~[spring-messaging-5.0.6.RELEASE.jar:5.0.6.RELEASE]
    at org.springframework.messaging.core.AbstractMessageSendingTemplate.convertAndSend(AbstractMessageSendingTemplate.java:149) ~[spring-messaging-5.0.6.RELEASE.jar:5.0.6.RELEASE]
    at org.springframework.messaging.core.AbstractMessageSendingTemplate.convertAndSend(AbstractMessageSendingTemplate.java:128) ~[spring-messaging-5.0.6.RELEASE.jar:5.0.6.RELEASE]
    at org.springframework.messaging.simp.annotation.support.SendToMethodReturnValueHandler.handleReturnValue(SendToMethodReturnValueHandler.java:188) ~[spring-messaging-5.0.6.RELEASE.jar:5.0.6.RELEASE]
    at org.springframework.messaging.handler.invocation.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:107) ~[spring-messaging-5.0.6.RELEASE.jar:5.0.6.RELEASE]
    at org.springframework.messaging.handler.invocation.AbstractMethodMessageHandler.handleMatch(AbstractMethodMessageHandler.java:527) [spring-messaging-5.0.6.RELEASE.jar:5.0.6.RELEASE]
    at org.springframework.messaging.simp.annotation.support.SimpAnnotationMethodMessageHandler.handleMatch(SimpAnnotationMethodMessageHandler.java:495) [spring-messaging-5.0.6.RELEASE.jar:5.0.6.RELEASE]
    at org.springframework.messaging.simp.annotation.support.SimpAnnotationMethodMessageHandler.handleMatch(SimpAnnotationMethodMessageHandler.java:88) [spring-messaging-5.0.6.RELEASE.jar:5.0.6.RELEASE]
    at org.springframework.messaging.handler.invocation.AbstractMethodMessageHandler.handleMessageInternal(AbstractMethodMessageHandler.java:473) [spring-messaging-5.0.6.RELEASE.jar:5.0.6.RELEASE]
    at org.springframework.messaging.handler.invocation.AbstractMethodMessageHandler.handleMessage(AbstractMethodMessageHandler.java:409) [spring-messaging-5.0.6.RELEASE.jar:5.0.6.RELEASE]
    at org.springframework.messaging.support.ExecutorSubscribableChannel$SendTask.run(ExecutorSubscribableChannel.java:138) [spring-messaging-5.0.6.RELEASE.jar:5.0.6.RELEASE]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_05]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_05]
    at java.lang.Thread.run(Thread.java:745) [na:1.8.0_05]
Solution

  • For now, I ended up using a GSON parser to stringify the custom object and return String.

    @MessageMapping("/path1")
@SendTo("/queue/path1-data")
public String myController(String message) throws Exception {
    Gson gson = new Gson();
    return gson.toJson(new BrokerPacket(message, "sdf", "asdf"));
}