启动Tomcat时老是报这个错，请各位大虾帮帮忙啊！！！！
严重: Exception starting filter struts2
Unable to load configuration. - [unknown location]
at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:431)
at org.apache.struts2.dispatcher.ng.InitOperations.initDispatcher(InitOperations.java:69)
at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.init(StrutsPrepareAndExecuteFilter.java:51)
at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:275)
at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:397)
at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:108)
at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:3696)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4343)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:791)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:771)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:525)
at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:920)
at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:883)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:492)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1138)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:311)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:719)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443)
at org.apache.catalina.core.StandardService.start(StandardService.java:516)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:710)
at org.apache.catalina.startup.Catalina.start(Catalina.java:566)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:288)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:413)
Caused by: Unable to load configuration. - [unknown location]
at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:58)
at org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java:374)
at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:418)
... 29 more
Caused by: Caught exception while loading file struts-default.xml - [unknown location]
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadConfigurationFiles(XmlConfigurationProvider.java:902)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadDocuments(XmlConfigurationProvider.java:143)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.init(XmlConfigurationProvider.java:110)
at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:168)
at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:55)
... 31 more
Caused by: java.lang.ClassCastException: org.apache.xerces.parsers.XML11Configuration cannot be cast to org.apache.xerces.xni.parser.XMLParserConfiguration
at org.apache.xerces.parsers.DOMParser.<init>(Unknown Source)
at org.apache.xerces.parsers.DOMParser.<init>(Unknown Source)
at org.apache.xerces.jaxp.DocumentBuilderImpl.<init>(Unknown Source)
at org.apache.xerces.jaxp.DocumentBuilderFactoryImpl.newDocumentBuilder(Unknown Source)
at com.sun.org.apache.xalan.internal.xsltc.trax.SAX2DOM.<init>(Unknown Source)
at com.sun.org.apache.xalan.internal.xsltc.runtime.output.TransletOutputHandlerFactory.getSerializationHandler(Unknown Source)
at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.getOutputHandler(Unknown Source)
at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerHandlerImpl.setResult(Unknown Source)
at com.opensymphony.xwork2.util.DomHelper$DOMBuilder.setup(DomHelper.java:205)
at com.opensymphony.xwork2.util.DomHelper$DOMBuilder.<init>(DomHelper.java:190)
at com.opensymphony.xwork2.util.DomHelper$DOMBuilder.<init>(DomHelper.java:181)
at com.opensymphony.xwork2.util.DomHelper$DOMBuilder.<init>(DomHelper.java:167)
at com.opensymphony.xwork2.util.DomHelper.parse(DomHelper.java:107)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadConfigurationFiles(XmlConfigurationProvider.java:893)
... 35 more
[解决办法]
不能加载配置文件 jar问题吧 你都导的什么包？
[解决办法]
把项目用的struts2的包换版本试试 移除web项目重新部署 换个tomcat版本等试试
[解决办法]
直接在网上下载一个新的tomcat试试。
[解决办法]
有可能是struts 2版本的问题。。。包倒错啦等情况。。。。。
[解决办法]
里面有两个Caused by你看一下，是不是配置文件的问题。struts 2的jar包有时候会跟其他的jar包冲突
[解决办法]
少了一个jar包 ，你到 struts2的示例war中找，我也忘了叫什么名字啦
[解决办法]
我也遇到这个错误着，是刚刚启动tomcat就报错，后来把javaee的版本从5改到四就好 了
