Question

我将此XML作为有效负载：

<root>
   <entry>
      <key>mobile_phone</key>
      <value>380929993314</value>
   </entry>
   <entry>
      <key>surname</key>
      <value>Dylan</value>
   </entry>
   <entry>
      <key>name</key>
      <value>Bob</value>
   </entry>
   <entry>
      <key>extension</key>
      <value>208</value>
   </entry>
   <entry>
      <key>mobile_extension</key>
      <value>608</value>
   </entry>
   <entry>
      <key>email</key>
      <value>bob@dylan.com</value>
   </entry>
</root>

和此有效载荷的Mule ESB流程：

<message-properties-transformer doc:name="Set Duty Properties" scope="session">
    <add-message-property key="dutyName" value="#[xpath('/root/entry/key[text()=&quot;name&quot;]/../value/text()').getText()]"/>
    <add-message-property key="dutySurname" value="#[xpath('/root/entry/key[text()=&quot;surname&quot;]/../value/text()').getText()]"/>
    <add-message-property key="dutyMobilePhone" value="#[xpath('/root/entry/key[text()=&quot;mobile_phone&quot;]/../value/text()').getText()]"/>
    <add-message-property key="dutyEmail" value="#[xpath('/root/entry/key[text()=&quot;email&quot;]/../value/text()').getText()]"/>
</message-properties-transformer>

这段代码工作原理很好，但有时候我的应用程序会出现这个错误：

ERROR 2013-11-17 15:42:42,712 [[duty-notifications].supportTicket.stage1.02] org.mule.exception.CatchMessagingExceptionStrategy: 
********************************************************************************
Message               : Execution of the expression "xpath('/root/entry/key[text()="mobile_phone"]/../value/text()').getText()" failed. (org.mule.api.expression.ExpressionRuntimeException). Message payload is of type: String
Code                  : MULE_ERROR--2
--------------------------------------------------------------------------------
Exception stack is:
1. [Error: unable to resolve method: java.util.ArrayList.getText() [arglength=0]]
[Near : {... xpath('/root/entry/key[text()= ....}]
             ^
[Line: 1, Column: 1] (org.mvel2.PropertyAccessException)
  org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer:1078 (null)
2. Execution of the expression "xpath('/root/entry/key[text()="mobile_phone"]/../value/text()').getText()" failed. (org.mule.api.expression.ExpressionRuntimeException)
  org.mule.el.mvel.MVELExpressionLanguage:218 (http://www.mulesoft.org/docs/site/current3/apidocs/org/mule/api/expression/ExpressionRuntimeException.html)
3. Execution of the expression "xpath('/root/entry/key[text()="mobile_phone"]/../value/text()').getText()" failed. (org.mule.api.expression.ExpressionRuntimeException). Message payload is of type: String (org.mule.api.transformer.TransformerMessagingException)
  org.mule.transformer.AbstractTransformer:139 (http://www.mulesoft.org/docs/site/current3/apidocs/org/mule/api/transformer/TransformerMessagingException.html)
--------------------------------------------------------------------------------
Root Exception stack trace:
[Error: unable to resolve method: java.util.ArrayList.getText() [arglength=0]]
[Near : {... xpath('/root/entry/key[text()= ....}]
             ^
[Line: 1, Column: 1]
      at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.getMethod(ReflectiveAccessorOptimizer.java:1078)
      at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.getMethod(ReflectiveAccessorOptimizer.java:987)
      at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.compileGetChain(ReflectiveAccessorOptimizer.java:377)
    + 3 more (set debug level logging or '-Dmule.verbose.exceptions=true' for everything)
********************************************************************************

即。由于不明原因，dutyMobilePhone的XPath函数有时会返回ArrayList for＆＃34; 380929993314＆＃34;而不是String（通常）。

请帮帮我。如何防止XPath函数的这种随机行为？

Answer 1

在您的Xpath表达式中，选择包含元素并从MEL获取其文本内容：

value="#[xpath('/root/entry/key[text()=&quot;mobile_phone&quot;]/../value').text]"

Answer 2

通过在XML中添加<?xml version="1.0" encoding="utf-8"?>标头解决。没有这个Mule XPath函数表现得很奇怪。

对于相同的值，Mule ESB XPath函数有时会返回ArrayList而不是String

2 个答案: