MULE：XPath表达式不提取有效载荷值(MULE: xpath expression not e

2019-09-30 08:55发布

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我有一个简单的流程，它需要一个XML消息，它分裂成子元素，现在我试图得到一个值，但得到意想不到的效果。

我的XML看起来是这样的： 

<?xml version="1.0" encoding="UTF-8" ?>
<ns0:RewardOfferDetail xmlns:ns0="http://example.com/schemas/v1_0/RewardOffer">
  <ns0:Offer>
    <ns0:OperationCode>U</ns0:OperationCode>
  </ns0:Offer>
  <ns0:Offer>
    <ns0:OperationCode>A</ns0:OperationCode>
  </ns0:Offer>
</ns0:RewardOfferDetail>

我需要提取<OpeartionCode>从各<Offer>

分割工作正常，当我在拆分后注销的有效载荷，它是一个<Offer>就好了。 但我尝试提取的值<OperationCode>使用此： 

#[xpath('/rewardsns:Offer/rewardns:OperationCode')]

我什么也没得到，只是一个空值，然后我尝试使用更广泛的XPath表达式： 

#[xpath('//rewardns:OperationCode')]

其结果是两个节点，这使我相信，XPath函数不看正确的位置。 但我甚至还试图告诉它到哪里寻找，仍然没有运气。 

#[xpath('//rewardns:OperationCode', message.payload)]
#[xpath('//rewardns:OperationCode', payload)]

还产生了两个节点。

有什么建议么？

流： 

    <flow name="receiveMessageFlow">
    <jms:inbound-endpoint
        queue="#{loyaltySettings.getString('loyalty.queue.receive')}"
        connector-ref="jmsConnector" doc:name="Loyalty Queue" />

    <message-filter doc:name="XSD Validation" onUnaccepted="invalidXmlMessage">
        <filter ref="schemaValidation" />
    </message-filter>

    <splitter expression="#[xpath('/rewardns:RewardOfferDetail/rewardns:Offer')]" doc:name="Split Message" />

    <set-variable variableName="action" value="#[xpath('//rewardns:OperationCode')]" doc:name="Save Action Code"/>

    <logger message="Action is: '#[flowVars.action]'" level="WARN" doc:name="Log Action Code"/>

输出： 

13:53:39,653 DEBUG [org.mule.transport.jms.MultiConsumerJmsMessageReceiver] (TIBCO EMS Session Dispatcher (741)) Message received it is of type: TibjmsTextMessage
13:53:39,653 DEBUG [org.mule.transport.jms.MultiConsumerJmsMessageReceiver] (TIBCO EMS Session Dispatcher (741)) Message received on Queue[M.ESS.ITM.LOYALTY.STARS.ItemMaint] (com.tibco.tibjms.TibjmsQueue)
13:53:39,653 DEBUG [org.mule.transport.jms.MultiConsumerJmsMessageReceiver] (TIBCO EMS Session Dispatcher (741)) Message CorrelationId is: 
13:53:39,653 DEBUG [org.mule.transport.jms.MultiConsumerJmsMessageReceiver] (TIBCO EMS Session Dispatcher (741)) Jms Message Id is: ID:EMS-SERVER.A305502CE7A4:995
13:53:39,653 DEBUG [org.mule.transport.jms.transformers.JMSMessageToObject] (TIBCO EMS Session Dispatcher (741)) Applying transformer JMSMessageToObject#218219976 (org.mule.transport.jms.transformers.JMSMessageToObject)
13:53:39,653 DEBUG [org.mule.transport.jms.transformers.JMSMessageToObject] (TIBCO EMS Session Dispatcher (741)) Object before transform: 
org.mule.DefaultMuleMessage
{
  id=998d2f50-13a0-11e5-b0f9-ac87a31af20c
  payload=com.tibco.tibjms.TibjmsTextMessage
  correlationId=
  correlationGroup=-1
  correlationSeq=-1
  encoding=UTF-8
  exceptionPayload=<not set>

Message properties:
  INVOCATION scoped properties:
  INBOUND scoped properties:
    JMSCorrelationID=
    JMSDeliveryMode=1
    JMSDestination=Queue[M.ESS.ITM.LOYALTY.STARS.ItemMaint]
    JMSExpiration=0
    JMSMessageID=ID:EMS-SERVER.A305502CE7A4:995
    JMSPriority=4
    JMSRedelivered=false
    JMSTimestamp=1426256459016
    JMSType=
    MULE_CORRELATION_ID=
    MULE_MESSAGE_ID=ID:EMS-SERVER.A305502CE7A4:995
  OUTBOUND scoped properties:
    MULE_ENCODING=UTF-8
  SESSION scoped properties:
}
13:53:39,654 DEBUG [org.mule.transport.jms.transformers.JMSMessageToObject] (TIBCO EMS Session Dispatcher (741)) Source object is TibjmsTextMessage
13:53:39,654 DEBUG [org.mule.transport.jms.transformers.JMSMessageToObject] (TIBCO EMS Session Dispatcher (741)) Message type received is: TibjmsTextMessage
13:53:39,654 DEBUG [org.mule.transport.jms.transformers.JMSMessageToObject] (TIBCO EMS Session Dispatcher (741)) Resulting object is String
13:53:39,654 DEBUG [org.mule.transport.jms.transformers.JMSMessageToObject] (TIBCO EMS Session Dispatcher (741)) Object after transform: <?xml version="1.0" encoding="UTF-8" ?>
<ns0:RewardOfferDetail xmlns:ns0="http://example.com/schemas/v1_0/RewardOffer">
  <ns0:Offer>
    <ns0:OperationCode>U</ns0:OperationCode>
  </ns0:Offer>
  <ns0:Offer>
    <ns0:OperationCode>A</ns0:OperationCode>
  </ns0:Offer>
</ns0:RewardOfferDetail>
13:53:39,654 DEBUG [org.mule.transport.jms.transformers.JMSMessageToObject] (TIBCO EMS Session Dispatcher (741)) The transformed object is of expected type. Type is: String
13:53:39,669 DEBUG [org.mule.expression.DefaultExpressionManager] ([loyalty-nebula].receiveMessageFlow.stage1.02) Result of expression: xpath-branch:/rewardns:RewardOfferDetail/rewardns:Offer is: [[ns0:Offer: null], [ns0:Offer: null]]
13:53:39,669 DEBUG [org.mule.processor.chain.DefaultMessageProcessorChain] ([loyalty-nebula].receiveMessageFlow.stage1.02) Invoking DefaultMessageProcessorChain '(inner iterating chain) of 'receiveMessageFlow' processor chain' 
[ 
  AddFlowVariableTransformer{this=589f1380, name='AddFlowVariableTransformer', ignoreBadInput=false, returnClass=SimpleDataType{type=java.lang.Object, mimeType='*/*'}, sourceTypes=[SimpleDataType{type=java.lang.Object, mimeType='*/*'}]}, 
  org.mule.api.processor.LoggerMessageProcessor@be3c4ce, 
  org.mule.routing.requestreply.AsyncReplyToPropertyRequestReplyReplier
] with event MuleEvent: 0-998d2f53-13a0-11e5-b0f9-ac87a31af20c, stop processing=false, jms://M.ESS.ITM.LOYALTY.STARS.ItemMaint
13:53:39,669 DEBUG [org.mule.transformer.simple.AddFlowVariableTransformer] ([loyalty-nebula].receiveMessageFlow.stage1.02) Applying transformer AddFlowVariableTransformer (org.mule.transformer.simple.AddFlowVariableTransformer)
13:53:39,670 DEBUG [org.mule.transformer.simple.AddFlowVariableTransformer] ([loyalty-nebula].receiveMessageFlow.stage1.02) Object before transform: 
org.mule.DefaultMuleMessage
{
  id=998fa050-13a0-11e5-b0f9-ac87a31af20c
  payload=org.apache.xerces.dom.ElementNSImpl
  correlationId=<not set>
  correlationGroup=2
  correlationSeq=1
  encoding=UTF-8
  exceptionPayload=<not set>

Message properties:
  INVOCATION scoped properties:
  INBOUND scoped properties:
  OUTBOUND scoped properties:
    MULE_CORRELATION_GROUP_SIZE=2
    MULE_CORRELATION_SEQUENCE=1
    MULE_ENCODING=UTF-8
  SESSION scoped properties:
}
13:53:39,670 DEBUG [org.mule.expression.DefaultExpressionManager] ([loyalty-nebula].receiveMessageFlow.stage1.02) Result of expression: xpath-branch://rewardns:OperationCode is: [[ns0:OperationCode: null], [ns0:OperationCode: null]]
13:53:39,670 DEBUG [org.mule.transformer.simple.AddFlowVariableTransformer] ([loyalty-nebula].receiveMessageFlow.stage1.02) Object after transform: 
org.mule.DefaultMuleMessage
{
  id=998fa050-13a0-11e5-b0f9-ac87a31af20c
  payload=org.apache.xerces.dom.ElementNSImpl
  correlationId=<not set>
  correlationGroup=2
  correlationSeq=1
  encoding=UTF-8
  exceptionPayload=<not set>

Message properties:
  INVOCATION scoped properties:
    action=[[ns0:OperationCode: null], [ns0:OperationCode: null]]
  INBOUND scoped properties:
  OUTBOUND scoped properties:
    MULE_CORRELATION_GROUP_SIZE=2
    MULE_CORRELATION_SEQUENCE=1
    MULE_ENCODING=UTF-8
  SESSION scoped properties:
}
13:53:39,671 DEBUG [org.mule.transformer.simple.AddFlowVariableTransformer] ([loyalty-nebula].receiveMessageFlow.stage1.02) The transformed object is of expected type. Type is: DefaultMuleMessage
13:53:39,672 WARN  [org.mule.api.processor.LoggerMessageProcessor] ([loyalty-nebula].receiveMessageFlow.stage1.02) Action is: '[[ns0:OperationCode: null], [ns0:OperationCode: null]]'

Answer 1:

该splitter产生具有消息Offer DOM元素作为其有效载荷。

如果使用XPath表达式开始//你正在导航回根元素，这仍然是通航从Offer元（因为分裂不分离的DOM节点）。

所以，你需要立足当前您的XPath Offer与元素： 

#[xpath('rewardns:OperationCode').nodeValue]

请注意，您也可以使用MEL而不是XPath来阅读的内容Offer DOM元素： 

<set-variable variableName="action"
    value="#[message.payload.getElementsByTagNameNS('http://example.com/schemas/v1_0/RewardOffer','OperationCode').nodeValue]"
    doc:name="Save Action Code"/>


Answer 2:

这似乎工作

    xpath('./rewardns:OperationCode')

从什么是@大卫解释似乎XPath的仍然可以在整个文档访问元素。 来解决这个问题的一种方法是使用一个./在表达锚定功能，使用当前节点作为起点。

所以，最后一个部分是这样的： 

    <set-variable variableName="action" value="#[xpath('./rewardns:OperationCode').getFirstChild().getNodeValue()]" doc:name="Save Action Code"/>


文章来源: MULE: xpath expression not extracting values from payload
标签： mule mule-studio mule-el
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