struts2.0配置问题

        初次使用Struts2.0，做登录的例子，一切准备工作做好之后启动服务器，总是报如下错误

 

Caused by: Document is invalid: no grammar found. - file:/C:/apache-tomcat-6.0.14/webapps/struts2.0/WEB-INF/classes/struts.xml:3:8
 at com.opensymphony.xwork2.util.DomHelper.parse(DomHelper.java:123)
 at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadConfigurationFiles(XmlConfigurationProvider.java:830)
 ... 34 more
Caused by: org.xml.sax.SAXParseException: Document is invalid: no grammar found.
 at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:236)
 at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.error(ErrorHandlerWrapper.java:172)
 at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:382)
 at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:316)
 at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement(XMLNSDocumentScannerImpl.java:177)
 at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl$NSContentDispatcher.scanRootElementHook(XMLNSDocumentScannerImpl.java:779)
 at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(XMLDocumentFragmentScannerImpl.java:1794)
 at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:368)
 at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:834)
 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:148)
 at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1242)
 at javax.xml.parsers.SAXParser.parse(SAXParser.java:375)
 at com.opensymphony.xwork2.util.DomHelper.parse(DomHelper.java:121)
 ... 35 more

 

折腾半天之后，发现Struts.xml这个文件没有

<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
    "http://struts.apache.org/dtds/struts-2.0.dtd">

格式定义

 

看来Struts2对配置文件格式要求很严格，都是没有经验惹的麻烦