Spring integration 使用MappingJackson2MessageConverter进行意外的消息转换

下面的代码段适用于5.0.8.RELASE，但在5.1.0.RELASE中失败

@Bean
public IntegrationFlow flow(RestTemplateBuilder restTemplateBuilder, MessageChannel outputChannel) {
    return f -> f
            .handle(Http.outboundGateway("http://localhost:80/test", restTemplateBuilder.build())
                    .httpMethod(HttpMethod.GET).expectedResponseType(String.class))
            .enrichHeaders(h -> h.header(JsonHeaders.TYPE_ID, Response.class))
            .transform(Transformers.fromJson())
            .filter(Response.class, p -> true)
            .channel(outputChannel);
}

public static class Response {
    private int result;
    public int getResult() { return result; }
    public void setResult(int result) { this.result = result; }
}

完整堆栈跟踪是：

org.springframework.messaging.converter.MessageConversionException: Could not read JSON: Unrecognized token 'org': was expecting ('true', 'false' or 'null')
at [Source: (String)"org.example.Application$Response@2d195ee4"; line: 1, column: 4]; nested exception is com.fasterxml.jackson.core.JsonParseException: Unrecognized token 'org': was expecting ('true', 'false' or 'null')
at [Source: (String)"org.example.Application$Response@2d195ee4"; line: 1, column: 4], failedMessage=GenericMessage [payload=org.example.Application$Response@2d195ee4, headers={id=a621f44f-dc89-19b6-6c80-f372c86e755d, contentType=application/json, http_statusCode=200 OK, timestamp=1542638474438}]
at org.springframework.messaging.converter.MappingJackson2MessageConverter.convertFromInternal(MappingJackson2MessageConverter.java:234)
at org.springframework.messaging.converter.AbstractMessageConverter.fromMessage(AbstractMessageConverter.java:181)
at org.springframework.messaging.converter.AbstractMessageConverter.fromMessage(AbstractMessageConverter.java:172)
at org.springframework.messaging.converter.CompositeMessageConverter.fromMessage(CompositeMessageConverter.java:57)
at org.springframework.integration.handler.LambdaMessageProcessor.processMessage(LambdaMessageProcessor.java:112)
at org.springframework.integration.filter.AbstractMessageProcessingSelector.accept(AbstractMessageProcessingSelector.java:62)
at org.springframework.integration.filter.MessageFilter.doHandleRequestMessage(MessageFilter.java:165)
at org.springframework.integration.handler.AbstractReplyProducingPostProcessingMessageHandler.handleRequestMessage(AbstractReplyProducingPostProcessingMessageHandler.java:46)
at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleMessageInternal(AbstractReplyProducingMessageHandler.java:123)
at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:169)
at org.springframework.integration.dispatcher.AbstractDispatcher.tryOptimizedDispatch(AbstractDispatcher.java:115)
at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:133)
at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:106)
at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:73)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:459)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:400)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:187)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:166)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:47)
at org.springframework.messaging.core.AbstractMessageSendingTemplate.send(AbstractMessageSendingTemplate.java:109)
at org.springframework.integration.handler.AbstractMessageProducingHandler.sendOutput(AbstractMessageProducingHandler.java:415)
at org.springframework.integration.handler.AbstractMessageProducingHandler.produceOutput(AbstractMessageProducingHandler.java:334)
at org.springframework.integration.handler.AbstractMessageProducingHandler.sendOutputs(AbstractMessageProducingHandler.java:225)
at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleMessageInternal(AbstractReplyProducingMessageHandler.java:129)
at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:169)
at org.springframework.integration.dispatcher.AbstractDispatcher.tryOptimizedDispatch(AbstractDispatcher.java:115)
at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:133)
at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:106)
at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:73)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:459)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:400)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:187)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:166)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:47)
at org.springframework.messaging.core.AbstractMessageSendingTemplate.send(AbstractMessageSendingTemplate.java:109)
at org.springframework.integration.handler.AbstractMessageProducingHandler.sendOutput(AbstractMessageProducingHandler.java:415)
at org.springframework.integration.handler.AbstractMessageProducingHandler.produceOutput(AbstractMessageProducingHandler.java:334)
at org.springframework.integration.handler.AbstractMessageProducingHandler.sendOutputs(AbstractMessageProducingHandler.java:225)
at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleMessageInternal(AbstractReplyProducingMessageHandler.java:129)
at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:169)
at org.springframework.integration.dispatcher.AbstractDispatcher.tryOptimizedDispatch(AbstractDispatcher.java:115)
at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:133)
at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:106)
at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:73)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:459)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:400)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:187)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:166)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:47)
at org.springframework.messaging.core.AbstractMessageSendingTemplate.send(AbstractMessageSendingTemplate.java:109)
at org.springframework.integration.handler.AbstractMessageProducingHandler.sendOutput(AbstractMessageProducingHandler.java:415)
at org.springframework.integration.handler.AbstractMessageProducingHandler.produceOutput(AbstractMessageProducingHandler.java:334)
at org.springframework.integration.handler.AbstractMessageProducingHandler.sendOutputs(AbstractMessageProducingHandler.java:225)
at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleMessageInternal(AbstractReplyProducingMessageHandler.java:129)
at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:169)
at org.springframework.integration.dispatcher.AbstractDispatcher.tryOptimizedDispatch(AbstractDispatcher.java:115)
at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:133)
at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:106)
at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:73)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:459)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:400)
at org.example.ApplicationTest.flow(ApplicationTest.java:46)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.springframework.test.context.junit4.statements.RunBeforeTestExecutionCallbacks.evaluate(RunBeforeTestExecutionCallbacks.java:74)
at org.springframework.test.context.junit4.statements.RunAfterTestExecutionCallbacks.evaluate(RunAfterTestExecutionCallbacks.java:84)
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:251)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:538)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:760)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:460)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:206)
Caused by: com.fasterxml.jackson.core.JsonParseException: Unrecognized token 'org': was expecting ('true', 'false' or 'null')
at [Source: (String)"org.example.Application$Response@2d195ee4"; line: 1, column: 4]
at com.fasterxml.jackson.core.JsonParser._constructError(JsonParser.java:1804)
at com.fasterxml.jackson.core.base.ParserMinimalBase._reportError(ParserMinimalBase.java:679)
at com.fasterxml.jackson.core.json.ReaderBasedJsonParser._reportInvalidToken(ReaderBasedJsonParser.java:2839)
at com.fasterxml.jackson.core.json.ReaderBasedJsonParser._handleOddValue(ReaderBasedJsonParser.java:1891)
at com.fasterxml.jackson.core.json.ReaderBasedJsonParser.nextToken(ReaderBasedJsonParser.java:749)
at com.fasterxml.jackson.databind.ObjectMapper._initForReading(ObjectMapper.java:4141)
at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4000)
at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3042)
at org.springframework.messaging.converter.MappingJackson2MessageConverter.convertFromInternal(MappingJackson2MessageConverter.java:229)
... 92 more

但是，如果注释掉了行

.filter（Response.class，p->true）

，它将按预期工作

出于某种原因，

MappingJackson2MessageConverter

被用作过滤器中的转换器，尽管我认为它不应该。事实上，5.1.0.RELEASE中用于过滤器的转换器与5.0.8.RELEASE中使用的转换器没有太多相似之处。在我看来，5.1.0.0版本中转换器的注册过程中出现了一些问题。这是否真的是预期的行为？在这种情况下，应如何调整代码

可以找到一个示例项目。请检查

org.example.FilterAfterJsonTransformation

和

org.example.FilterAfterJsonTransformationTest

。通过切换版本和/或评论前面提到的行，在错误和正确行为之间切换。

这确实是一个bug（很快就会修复）

同时，您应该避免使用带有额外类参数的

filter（）

。如果在filter函数中仍然需要该类型，则需要手动执行显式强制转换

另一个技巧是删除

contentType

头，以避免

MappingJackson2MessageConverter

执行其转换逻辑

更新

---

关于该问题的请求：

我们可以得到关于该问题的整个堆栈跟踪吗？在GitHub上的某个地方有一个简单的项目可以玩也很好。添加

.headerFilter（“contentType”）

确实解决了这个问题。作为旁注，为什么要避免使用带有额外类参数的

filter（）

，应该使用什么？也许像

.filter（p->doSomething（p））

这样的东西更合适？对。这也很好。在您的情况下，我们需要以某种方式避免双重转换。我们只是没有对这件事进行任何测试！