java - 必须为元素 "type"异常声明属性 "forward".. 它是关于什么的..？我们必须做出什么改变..？

Question

每当我启动网络应用程序时，我都会收到以下异常.. 我们必须做出什么改变..？我们是否必须将 type 属性添加到 struts-config.xml 的前向标记..？如果是这样，type 属性可能取什么值？

SEVERE: Parse Error at line 23 column 67: Attribute "type" must be declared for element    type "forward".
org.xml.sax.SAXParseException; systemId: jndi:/localhost/TilesStruts/WEB-INF/struts-config.xml; lineNumber: 23; columnNumber: 67; Attribute "type" must be declared for element type "forward".
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.addDTDDefaultAttrsAndValidate(XMLDTDValidator.java:1253)
at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.handleStartElement(XMLDTDValidator.java:1917)
at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.emptyElement(XMLDTDValidator.java:763)
at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement(XMLNSDocumentScannerImpl.java:353)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2715)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:607)
at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:116)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:488)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:835)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:764)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:123)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1210)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:568)
at org.apache.commons.digester.Digester.parse(Digester.java:1827)
at org.apache.struts.action.ActionServlet.parseModuleConfigFile(ActionServlet.java:740)
at org.apache.struts.action.ActionServlet.initModuleConfig(ActionServlet.java:689)
at org.apache.struts.action.ActionServlet.init(ActionServlet.java:356)
at javax.servlet.GenericServlet.init(GenericServlet.java:160)
at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1280)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1193)
at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1088)
at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:5123)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5407)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:633)
at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:656)
at org.apache.catalina.startup.HostConfig$DeployDescriptor.run(HostConfig.java:1635)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
at java.util.concurrent.FutureTask.run(FutureTask.java:166)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:722)

添加了 struts_config.xml 文件

<?xml version="1.0" encoding="UTF-8" ?>

<!DOCTYPE struts-config PUBLIC
      "-//Apache Software Foundation//DTD Struts Configuration 1.3//EN"
      "http://jakarta.apache.org/struts/dtds/struts-config_1_3.dtd">


<struts-config>
<form-beans>
    <form-bean name="EmployeeForm" type="com.myapp.example.EmployeeForm"/>

</form-beans>

<global-exceptions>

</global-exceptions>

<global-forwards>
    <forward name="welcome"  path="/Welcome.do"/>
</global-forwards>

<action-mappings>
    <action input="/testListener.jsp" name="EmployeeForm"
       parameter="method"     path="/EmployeeAction" scope="session" type="com.myapp.example.EmployeeAction">
       <!--parameter is request parameter name-->
        <forward name="success" path="/success.jsp"  />
    <forward name="failure" path="/failure.jsp" />
    </action>
    <action path="/Welcome" forward="/testListener.jsp"/>
</action-mappings>

<controller processorClass="org.apache.struts.tiles.TilesRequestProcessor"/>

<message-resources parameter="com/myapp/struts/ApplicationResource"/>    

<!-- ========================= Tiles plugin ===============================-->
<!--
This plugin initialize Tiles definition factory. This later can takes some
parameters explained here after. The plugin first read parameters from
web.xml, thenoverload them with parameters defined here. All parameters
are optional.
The plugin should be declared in each struts-config file.
- definitions-config: (optional)
Specify configuration file names. There can be several comma
separated file names (default: ?? )
- moduleAware: (optional - struts1.1)
Specify if the Tiles definition factory is module aware. If true
(default), there will be one factory for each Struts module.
If false, there will be one common factory for all module. In this
later case, it is still needed to declare one plugin per module.
The factory will be initialized with parameters found in the first
initialized plugin (generally the one associated with the default
module).
true : One factory per module. (default)
false : one single shared factory for all modules
- definitions-parser-validate: (optional)
Specify if xml parser should validate the Tiles configuration file.
true : validate. DTD should be specified in file header (default)
false : no validation

Paths found in Tiles definitions are relative to the main context.
-->
<plug-in className="org.apache.struts.tiles.TilesPlugin" >
    <set-property property="definitions-config" value="/WEB-INF/tiles-defs.xml" />      
    <set-property property="moduleAware" value="true" />
</plug-in>

<!-- ========================= Validator plugin ================================= -->
<plug-in className="org.apache.struts.validator.ValidatorPlugIn">
    <set-property
        property="pathnames"
        value="/WEB-INF/validator-rules.xml,/WEB-INF/validation.xml"/>
</plug-in>

</struts-config>

Answer 1

在 Struts 2 中，当您返回带有操作结果标记的图 block 时，应提及 type="tiles"，如下所示:

    <action name="sampleAction"
        class="com.struts2.SampleAction">
        <result name="success" type="tiles">tile1</result>
    </action>