如何在 Struts 2 中声明“未知处理程序”？

Question

我一直在研究如何使用 Spring 和 Struts2 解决 Java Enterprise 中的错误 404 和 NoSuchMethodException 昨天我读到，unknownhandlers 可以帮助我解决这些问题。

我已将其放入我的 struts.xml：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
  <bean name="unknownhandler" type="com.opensymphony.xwork2.UnknownHandler" class="UnknownActionHandler"/>

  <unknown-handler-stack>
    <unknown-handler-ref name="unknownhandler"/>
    <!--<unknown-handler-ref name="error" />-->
  </unknown-handler-stack>

  <constant name="struts.ui.theme" value="simple"/>
  <constant name="struts.objectFactory.spring.autoWire" value="name"/>
  <constant name="struts.locale" value="es_MX" />
  <constant name="struts.i18n.encoding" value="UTF-8" />    
  <constant name="struts.custom.i18n.resources" value="org.aporta.model.resources.etiquetas, org.aporta.bss.resources.CodesBss"/> 
  <constant name="struts.devMode" value="true" />
  <constant name="struts.configuration.xml.reload" value="true"/>
  <constant name="struts.enable.DynamicMethodInvocation" value="true" />

  ...more code

</struts>

当我运行项目时，我得到了这个错误：

org.xml.sax.SAXParseException; systemId: file:/home/paulfelix/Documents/workingit/portal/src/java/portal.xml; lineNumber: 33; columnNumber: 26; Element type "unknown-handler-stack" must be declared.
at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:198)
at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.error(ErrorHandlerWrapper.java:134)
at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:437)
at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:368)
at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:325)
at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.handleStartElement(XMLDTDValidator.java:1906)
at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.startElement(XMLDTDValidator.java:742)
at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement(XMLNSDocumentScannerImpl.java:378)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2770)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:606)
at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:117)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:510)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:848)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:777)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1213)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:649)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl.parse(SAXParserImpl.java:333)
at com.opensymphony.xwork2.util.DomHelper.parse(DomHelper.java:117)

...more code below.

在哪里可以声明未知的处理程序堆栈？

谁能给我一个如何实现未知处理程序的清晰示例？

Answer 1

DTD 通常是你的朋友；知道如何阅读可以节省大量时间：

<!ELEMENT struts ((package|include|bean|constant)*, unknown-handler-stack?)>

即在配置文件的末尾。

请注意，它们仅在 ~2.1 之后可用。