Java 从AMQP到RESTful端点的驼峰路由

我是骆驼队的新手，到目前为止，我一直玩得很开心。但是，我现在在尝试从AMQP读取消息并使用消息中的参数调用REST端点时遇到了一个问题

这个想法是AMQP消息包含一个POJO，我正在读取它以获取邮政编码和门牌号值。然后，这些值将用于填充URL中的动态字段。 我正在使用HTTP4执行对REST端点的调用，每次我点击该行时，我都会收到：

Message History
---------------------------------------------------------------------------------------------------------------------------------------
RouteId              ProcessorId          Processor                                                                        Elapsed (ms)
[route1            ] [route1            ] [spring-amqp://myExchange:getAddress:camel.getAddress?autodelete=false&durable=] [        46]
[route1            ] [log1              ] [log                                                                           ] [        13]
[route1            ] [setHeader1        ] [setHeader[CamelHttpUrl]                                                       ] [         0]
[route1            ] [setExchangePattern] [setExchangePattern[InOut]                                                     ] [         0]
[route1            ] [setHeader2        ] [setHeader[postcode]                                                           ] [        18]
[route1            ] [setHeader3        ] [setHeader[houseNumber]                                                        ] [         1]
[route1            ] [log2              ] [log                                                                           ] [         0]
[route1            ] [recipientList1    ] [recipientList[simple{Simple: https4:{{addressmicroservice.address.url}}/${head] [        13]

Stacktrace
---------------------------------------------------------------------------------------------------------------------------------------
org.apache.camel.InvalidPayloadException: No body available of type: java.io.InputStream but has value: Address [houseNumber=null, postcode=DY10 4TW, line1=null, line2=null, line3=null, line4=null, locality=null, town=null, county=null] of type: uk.gov.insolvency.microservices.pojos.Address on: Message[ID-Andrews-MacBook-Pro-local-56293-1472721966485-0-3]. Caused by: No type converter available to convert from type: uk.gov.insolvency.microservices.pojos.Address to the required type: java.io.InputStream with value Address [houseNumber=null, postcode=DY10 4TW, line1=null, line2=null, line3=null, line4=null, locality=null, town=null, county=null]. Exchange[ID-Andrews-MacBook-Pro-local-56293-1472721966485-0-4]. Caused by: [org.apache.camel.NoTypeConversionAvailableException - No type converter available to convert from type: uk.gov.insolvency.microservices.pojos.Address to the required type: java.io.InputStream with value Address [houseNumber=null, postcode=DY10 4TW, line1=null, line2=null, line3=null, line4=null, locality=null, town=null, county=null]]
at org.apache.camel.impl.MessageSupport.getMandatoryBody(MessageSupport.java:107)
at org.apache.camel.component.http4.HttpProducer.createRequestEntity(HttpProducer.java:523)
at org.apache.camel.component.http4.HttpProducer.createMethod(HttpProducer.java:422)
at org.apache.camel.component.http4.HttpProducer.process(HttpProducer.java:110)
at org.apache.camel.util.AsyncProcessorConverterHelper$ProcessorToAsyncProcessorBridge.process(AsyncProcessorConverterHelper.java:61)
at org.apache.camel.processor.RedeliveryErrorHandler.process(RedeliveryErrorHandler.java:468)
at org.apache.camel.processor.CamelInternalProcessor.process(CamelInternalProcessor.java:190)
at org.apache.camel.processor.MulticastProcessor.doProcessSequential(MulticastProcessor.java:681)
at org.apache.camel.processor.MulticastProcessor.doProcessSequential(MulticastProcessor.java:609)
at org.apache.camel.processor.MulticastProcessor.process(MulticastProcessor.java:238)
at org.apache.camel.processor.RecipientList.sendToRecipientList(RecipientList.java:170)
at org.apache.camel.processor.RecipientList.process(RecipientList.java:131)
at org.apache.camel.processor.Pipeline.process(Pipeline.java:121)
at org.apache.camel.processor.Pipeline.process(Pipeline.java:83)
at org.apache.camel.management.InstrumentationProcessor.process(InstrumentationProcessor.java:77)
at org.apache.camel.processor.RedeliveryErrorHandler.process(RedeliveryErrorHandler.java:468)
at org.apache.camel.processor.CamelInternalProcessor.process(CamelInternalProcessor.java:190)
at org.apache.camel.processor.Pipeline.process(Pipeline.java:121)
at org.apache.camel.processor.Pipeline.process(Pipeline.java:83)
at org.apache.camel.processor.CamelInternalProcessor.process(CamelInternalProcessor.java:190)
at org.apache.camel.util.AsyncProcessorHelper.process(AsyncProcessorHelper.java:109)
at org.apache.camel.processor.DelegateAsyncProcessor.process(DelegateAsyncProcessor.java:91)
at amqp.spring.camel.component.SpringAMQPConsumer$RabbitMQMessageListener.onMessage(SpringAMQPConsumer.java:201)
at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.doInvokeListener(AbstractMessageListenerContainer.java:757)
at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.invokeListener(AbstractMessageListenerContainer.java:680)
at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.access$001(SimpleMessageListenerContainer.java:93)
at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer$1.invokeListener(SimpleMessageListenerContainer.java:183)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:302)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
at org.springframework.retry.interceptor.StatefulRetryOperationsInterceptor$MethodInvocationRetryCallback.doWithRetry(StatefulRetryOperationsInterceptor.java:162)
at org.springframework.retry.support.RetryTemplate.doExecute(RetryTemplate.java:276)
at org.springframework.retry.support.RetryTemplate.execute(RetryTemplate.java:201)
at org.springframework.retry.interceptor.StatefulRetryOperationsInterceptor.invoke(StatefulRetryOperationsInterceptor.java:137)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:208)
at com.sun.proxy.$Proxy50.invokeListener(Unknown Source)
at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.invokeListener(SimpleMessageListenerContainer.java:1358)
at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.executeListener(AbstractMessageListenerContainer.java:661)
at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.doReceiveAndExecute(SimpleMessageListenerContainer.java:1102)
at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.receiveAndExecute(SimpleMessageListenerContainer.java:1086)
at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.access$1100(SimpleMessageListenerContainer.java:93)
at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer$AsyncMessageProcessingConsumer.run(SimpleMessageListenerContainer.java:1203)
at amqp.spring.camel.component.SpringAMQPConsumer$SpringAMQPExecutorTask.run(SpringAMQPConsumer.java:316)
at amqp.spring.camel.component.SpringAMQPConsumer$SpringAMQPExecutorTask.run(SpringAMQPConsumer.java:316)
at java.lang.Thread.run(Thread.java:745)
Caused by: org.apache.camel.NoTypeConversionAvailableException: No type converter available to convert from type: uk.gov.insolvency.microservices.pojos.Address to the required type: java.io.InputStream with value Address [houseNumber=null, postcode=DY10 4TW, line1=null, line2=null, line3=null, line4=null, locality=null, town=null, county=null]
at org.apache.camel.impl.converter.BaseTypeConverterRegistry.mandatoryConvertTo(BaseTypeConverterRegistry.java:198)
at org.apache.camel.impl.MessageSupport.getMandatoryBody(MessageSupport.java:105)
... 49 common frames omitted

我尝试创建的路由是：

from("spring-amqp:myExchange:getAddress:camel.getAddress?type=topic&durable=true&autodelete=false")
    .log("${body}")
    .setHeader(Exchange.HTTP_URL,
              constant("https://api.getAddress.io"))
    .setExchangePattern(ExchangePattern.InOut)
    .setHeader("postcode",
              simple("${body.postcode}"))
    .setHeader("houseNumber",
              simple("${body.houseNumber}"))
    .log("${headers}")
    .recipientList(simple("https4:{{addressmicroservice.address.url}}/${header.postcode}/${header.houseNumber}?{{addressmicroservice.address.key}}={{addressmicroservice.address.password}}&throwExceptionOnFailure=false&bridgeEndpoint=true"))
    .process(processor)
    .log("${body}");

---

使用Camel 2.17.2和Java 8。

从错误日志中，您需要在端点之间交换消息时转换消息，您可以参考这一点，或者您可以将消息封送/解封为xml/json以备选择

使用camel，您只需调用marshal（）即可添加封送json功能，如

尝试编组：

from("spring-amqp:myExchange:getAddress:camel.getAddress?type=topic&durable=true&autodelete=false")
    .log("${body}")
    .setHeader(Exchange.HTTP_URL,
              constant("https://api.getAddress.io"))
    .setExchangePattern(ExchangePattern.InOut)
    .setHeader("postcode",
              simple("${body.postcode}"))
    .setHeader("houseNumber",
              simple("${body.houseNumber}"))
    .log("${headers}")
    .marshal().json(Gson).convertBodyTo(String.class)
    .recipientList(simple("https4:{{addressmicroservice.address.url}}/${header.postcode}/${header.houseNumber}?{{addressmicroservice.address.key}}={{addressmicroservice.address.password}}&throwExceptionOnFailure=false&bridgeEndpoint=true"))
    .process(processor)
    .log("${body}");

请记住，您需要camel gson来实现这一点。供渐变使用：

 compile('org.apache.camel:camel-gson:2.17.1')

---

并根据您的驼峰版本进行调整。

是正确的，您需要将您的身体整理成适当的格式。我只有一个额外的评论-你可以使用

toD（“uri”）

，而不是使用

recipientList（simple（“uri”）

，更简短、更简洁：）@MilošMilivojević我之前尝试过toD，但在其他地方读到recipientList（simple（“uri”）是动态url的更好的方式。不管怎样，我同意toD更短、更干净，并且已经将它改回来了（虽然不是在示例中）。好吧，recipientList肯定更强大，但我更喜欢在大多数情况下更简单的方法。^^这帮助我找到了我想要的答案。我还添加了一个TypeConverter来将对象转换为InputStream，并在camel TypeConverter文件中添加了它来列出它。

 compile('org.apache.camel:camel-gson:2.17.1')