我遇到了Mule Dataweave Transformer的问题
INFO 2017-08-10 15:05:52,787 [amqpReceiver.02] org.mule.api.processor.LoggerMessageProcessor: Authorisation Changed Event received. authorisation id: 1
INFO 2017-08-10 15:05:57,844 [amqpReceiver.02] org.mule.api.processor.LoggerMessageProcessor: type before class com.mulesoft.weave.reader.ByteArraySeekableStream
INFO 2017-08-10 15:06:02,058 [amqpReceiver.02] org.mule.api.processor.LoggerMessageProcessor: type after: class com.mulesoft.weave.reader.ByteArraySeekableStream
INFO 2017-08-10 15:06:13,309 [amqpReceiver.02] org.mule.api.processor.LoggerMessageProcessor: Org Name :- Id:- Org Name 3
ERROR 2017-08-10 15:06:15,520 [amqpReceiver.02] org.mule.exception.RollbackMessagingExceptionStrategy:
********************************************************************************
Message : Exception while executing:
{
^
Unexpected end-of-input at index 0 (line 1, position 1), expected JSON Value
Payload : com.mulesoft.weave.reader.ByteArraySeekableStream@a622be8
Element : /subscribe-to-changeFlow/processors/8 @ voa-009-mule-authorisation-search-api:test.xml:60 (Final Transform Message)
Element XML : <dw:transform-message doc:name="Final Transform Message" metadata:id="fa7e7663-50bb-4675-a8c8-e8cb311946a9">
<dw:input-payload mimeType="application/json"></dw:input-payload>
<dw:set-payload resource="classpath:dwl/owner-authorisation-enrichment.dwl"></dw:set-payload>
</dw:transform-message>
--------------------------------------------------------------------------------
Root Exception stack trace:
com.mulesoft.weave.reader.json.JsonReaderException: Unexpected end-of-input at index 0 (line 1, position 1), expected JSON Value
at com.mulesoft.weave.reader.json.JsonTokenizer.fail(JsonTokenizer.scala:193)
at com.mulesoft.weave.reader.json.JsonTokenizer.readValue(JsonTokenizer.scala:49)
at com.mulesoft.weave.reader.json.JsonTokenizer.tokens(JsonTokenizer.scala:16)
at com.mulesoft.weave.reader.json.JsonReader.root(JsonReader.scala:17)
at com.mulesoft.weave.mule.reader.ReusableReader.root(ReusableReader.scala:12)
at com.mulesoft.weave.engine.EvaluationContext$InternalExecutionContext$$anonfun$3.apply(EvaluationContext.scala:106)
为了从JSON中提取一些值，我使用的是json：json-to-object-transformer，但是我把它放在一个以flowVar为目标的richver中，允许转换为map并保留原始值有效载荷完整
<enricher target="#[flowVars.ownerAuthorisationJsonMap]" doc:name="Copy to JSON map">
<json:json-to-object-transformer returnClass="java.util.HashMap" doc:name="JSON to Object"/>
</enricher>
然后，我调用子流程以获得更多日期以便稍后进行充实。子流仅将更丰富的结果存储在另一个flowVar
第二个Dataweave Transformer（获取异常）从第一个Dataweave Transformer获取JSON模式输出，并使用子流查找的数据来丰富一些缺失值（示例显示了一个，但Map中会有很多）。这是例外。
但是如果我用嵌套的 json-to-object-transformer
注释掉 richher <enricher target="#[flowVars.ownerAuthorisationJsonMap]" doc:name="Copy to JSON map">
<json:json-to-object-transformer returnClass="java.util.HashMap" doc:name="JSON to Object"/>
</enricher>
第二个数据网络正常（但我无法访问JSON中的数据）。似乎json-to-object-transformer让事情变得更糟，但如果我调试有效负载类型并且java对象id始终保持不变。
我只使用json-to-object-transformer来允许MEL访问JSON，因为似乎建议不要使用JSON-path。
<?xml version="1.0" encoding="UTF-8"?>
<amqp:endpoint name="authorisationChangeQueueDef"
queueName="authorisation-change-queue" queueDurable="true"
exchangeName="authorisation-exchange" exchangeType="direct" exchangeDurable="true"
connector-ref="AMQP_Connector"
routingKey="authorisation-change-queue-routing-key" doc:name="authorisationChangeQueueDef">
<properties>
<spring:entry key="amqp-queue.x-dead-letter-exchange" value="authorisation-exchange" />
<spring:entry key="amqp-queue.x-dead-letter-routing-key" value="authorisation-change-queue-dead-routing-key" />
</properties>
</amqp:endpoint>
<flow name="subscribe-to-changeFlow" processingStrategy="synchronous">
<amqp:inbound-endpoint ref="authorisationChangeQueueDef" responseTimeout="10000" doc:name="authorisation-change-consumer" />
<set-variable variableName="authorisationId" value="#[message.payloadAs(java.lang.String)]" doc:name="set authorisation id"/>
<logger message="#['Authorisation Changed Event received. authorisation id: ' + flowVars.authorisationId]" level="INFO" doc:name="Logger"/>
<http:request config-ref="Mule_Authorisation_Management_API_HTTP_Request_Configuration" path="#['/authorisation/' + flowVars.authorisationId]" method="GET" doc:name="HTTP REST call to Authorisation API"/>
<dw:transform-message doc:name="Transform to basic owner-authorisation" metadata:id="1bdd6f7e-6b4b-415b-819d-e88b9ff7f92b">
<dw:input-payload mimeType="application/json"/>
<dw:set-payload resource="dwl/owner-authorisation-skeleton.dwl"/>
</dw:transform-message>
<logger message="#['type before ' + message.dataType.type]" level="INFO" doc:name="Logger"/>
<!-- Enricher targeting flowVar to keep original payload type intact -->
<enricher target="#[flowVars.ownerAuthorisationJsonMap]" doc:name="Copy to JSON map">
<json:json-to-object-transformer returnClass="java.util.HashMap" doc:name="JSON to Object"/>
</enricher>
<logger message="#['type after: ' + message.dataType.type]" level="INFO" doc:name="Logger"/>
<!-- subflow that uses flowVars.ownerAuthorisationJsonMap and MEL -->
<flow-ref name="enrich-Sub_Flow" doc:name="enrich-Sub_Flow"/>
<dw:transform-message doc:name="Final Transform Message" metadata:id="fa7e7663-50bb-4675-a8c8-e8cb311946a9">
<dw:input-payload mimeType="application/json"/>
<dw:set-payload resource="classpath:dwl/owner-authorisation-enrichment.dwl"/>
</dw:transform-message>
<logger level="INFO" doc:name="Logger all "/>
<!-- Does a manual ACK to RabbitMQ, only do once we know all the processing is complete -->
<amqp:acknowledge-message doc:name="AMQP-0-9 Acknowledge Message"/>
<rollback-exception-strategy maxRedeliveryAttempts="3" doc:name="Rollback Exception Strategy">
<logger message="#['REQUESTING RETRY OF REQUEST... delivery-tag : ' + message.inboundProperties['delivery-tag']]" level="INFO" doc:name="Logger"/>
<!-- re-queue message for re-tries -->
<amqp:reject-message requeue="true" doc:name="AMQP-0-9 Reject Message" />
<on-redelivery-attempts-exceeded>
<logger message="REDELIVERY EXHAUSTED" level="ERROR" doc:name="Logger"/>
<amqp:reject-message doc:name="AMQP-0-9 Reject Message" />
</on-redelivery-attempts-exceeded>
</rollback-exception-strategy>
</flow>
<sub-flow name="enrich-Sub_Flow">
<set-variable variableName="organisationId" value="#[ownerAuthorisationJsonMap.organisationId]" doc:name="Extract Organisation Id" encoding="UTF-8" mimeType="application/json"/>
<enricher target="#[flowVars.organisationName]" source="#[payload.organisationLatestDetail.organisationName]" doc:name="Message Enricher">
<processor-chain doc:name="Processor Chain">
<flow-ref name="get-organisation-details-SubFlow" doc:name="get-organisation-details-Sub_Flow" />
<json:json-to-object-transformer returnClass="java.util.HashMap" doc:name="JSON to Object"/>
<logger level="INFO" message="Org Name :- Id:- #[payload.organisationLatestDetail.organisationName]" doc:name="Logger"/>
</processor-chain>
</enricher>
</sub-flow>
<sub-flow name="get-organisation-details-SubFlow">
<http:request config-ref="VOA_Mule_Customer_Management_API_HTTP_Request_Configuration" path="#['/organisation?organisationId='+ flowVars.organisationId]" method="GET"
doc:name="HTTP - Get Customer details">
</http:request>
</sub-flow>
Dataweave 1
%dw 1.0
%output application/json
---
{
authorisationId: payload.id,
uarn: payload.uarn,
authorisedParties: payload.parties map ((party , indexOfParty) -> {
organisationId: party.authorisedPartyOrganisationId,
status: party.authorisedPartyStatus,
startDate: party.startDate
}),
endDate: payload.endDate,
organisationId: payload.authorisationOwnerOrganisationId,
propertyLinkSubmissionId: payload.submissionId,
startDate: payload.startDate,
status: payload.authorisationStatus
}
Dataweave 2（这也将从Java Map进一步映射）
%dw 1.0
%output application/json
---
{
authorisationId: payload.authorisationId,
authorisedParties: payload.authorisedParties map ((authorisedParty , indexOfAuthorisedParty) -> {
organisationId: authorisedParty.organisationId,
startDate: authorisedParty.startDate,
status: authorisedParty.status
}),
endDate: payload.endDate,
organisationId: payload.organisationId,
organisationName: flowVars.organisationName,
propertyLinkSubmissionId: payload.propertyLinkSubmissionId,
startDate: payload.startDate,
status: payload.status,
uarn: payload.uarn
}
日志
INFO 2017-08-10 15:05:52,787 [amqpReceiver.02] org.mule.api.processor.LoggerMessageProcessor: Authorisation Changed Event received. authorisation id: 1
INFO 2017-08-10 15:05:57,844 [amqpReceiver.02] org.mule.api.processor.LoggerMessageProcessor: type before class com.mulesoft.weave.reader.ByteArraySeekableStream
INFO 2017-08-10 15:06:02,058 [amqpReceiver.02] org.mule.api.processor.LoggerMessageProcessor: type after: class com.mulesoft.weave.reader.ByteArraySeekableStream
INFO 2017-08-10 15:06:13,309 [amqpReceiver.02] org.mule.api.processor.LoggerMessageProcessor: Org Name :- Id:- Org Name 3
答案 0 :(得分：1)
问题是由json到对象转换器消耗的json有效负载流引起的，并且没有被重置，尽管它在消息丰富中。 请参阅此问题 - https://www.mulesoft.org/jira/browse/MULE-10623。
最简单的解决方案是在消息丰富后重置流：
...
<enricher target="#[flowVars.myMar]" doc:name="Message Enricher">
<json:json-to-object-transformer doc:name="JSON to Object"/>
</enricher>
<expression-component doc:name="Expression">
<![CDATA[payload.seek(0);]]>
</expression-component>
...
或在使用消息扩充器之前将有效负载转换为字符串：
...
<object-to-string-transformer doc:name="Object to String"/>
<enricher target="#[flowVars.myMar]" doc:name="Message Enricher">
...
仅供参考，我用这个简单的流程重复了这个问题：
<flow name="flow">
<dw:transform-message doc:name="Transform Message">
<dw:set-payload>
<![CDATA[%dw 1.0
%output application/json
---
{
foo:0
}]]>
</dw:set-payload>
</dw:transform-message>
<enricher target="#[flowVars.myVar]" doc:name="Message Enricher">
<json:json-to-object-transformer doc:name="JSON to Object"/>
</enricher>
<dw:transform-message doc:name="Transform Message">
<dw:set-payload>
<![CDATA[%dw 1.0
%output application/json
---
payload
]]>
</dw:set-payload>
</dw:transform-message>
</flow>