使用 @sendto 将我的自定义对象数据推送到消息队列

Question

我正在使用带有websockets的spring消息传递。目前我有一个@MessageMapping控制器来从 websocket 客户端获取数据。

@MessageMapping("/path1")
@SendTo("/queue/path1-data")
public BrokerPacket myController(String message) throws Exception {
    return new BrokerPacket(message, "1234", "5677");
}

我的代理数据包如下所示：

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;
    }
}

这给了我一个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]

Answer 1

现在，我最终使用 GSON 解析器来字符串化自定义对象并返回 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"));
}