这个问题真是奇怪呀，都来看看

先说在什么情况下出现这个错误。当我重启Tomcat服务器时都不报这个错，但是当我重新发布项目的时候就报这个错，错误信息如下：
17:07:31,585 ERROR Dispatcher:38 - Dispatcher initialization failed
Unable to load configuration. - [unknown location]
at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:69)
at org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java:371)
at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:415)
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:3800)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4450)
at org.apache.catalina.startup.HostConfig.checkResources(HostConfig.java:1173)
at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1271)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:296)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1337)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1601)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1610)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1590)
at java.lang.Thread.run(Thread.java:619)
Caused by: Caught exception while loading file struts-default.xml - [unknown location]
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadConfigurationFiles(XmlConfigurationProvider.java:913)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadDocuments(XmlConfigurationProvider.java:154)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.init(XmlConfigurationProvider.java:121)
at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:179)
at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:66)
... 18 more
Caused by: java.lang.ClassCastException: org.apache.xerces.parsers.XML11Configuration cannot be cast to org.apache.xerces.xni.parser.XMLParserConfiguration
at org.apache.xerces.parsers.DOMParser.<init>(Unknown Source)
at org.apache.xerces.parsers.DOMParser.<init>(Unknown Source)
at org.apache.xerces.jaxp.DocumentBuilderImpl.<init>(Unknown Source)
at org.apache.xerces.jaxp.DocumentBuilderFactoryImpl.newDocumentBuilder(Unknown Source)
at com.sun.org.apache.xalan.internal.xsltc.trax.SAX2DOM.<init>(SAX2DOM.java:69)
at com.sun.org.apache.xalan.internal.xsltc.runtime.output.TransletOutputHandlerFactory.getSerializationHandler(TransletOutputHandlerFactory.java:187)
at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.getOutputHandler(TransformerImpl.java:392)
at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerHandlerImpl.setResult(TransformerHandlerImpl.java:137)
at com.opensymphony.xwork2.util.DomHelper$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$DOMBuilder.<init>(DomHelper.java:167)
at com.opensymphony.xwork2.util.DomHelper.parse(DomHelper.java:107)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadConfigurationFiles(XmlConfigurationProvider.java:904)
... 22 more
2012-11-30 17:07:31 org.apache.catalina.core.StandardContext filterStart
严重: Exception starting filter struts2
Unable to load configuration. - [unknown location]
at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:428)
at org.apache.struts2.dispatcher.ng.InitOperations.initDispatcher(InitOperations.java:69)
at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.init(StrutsPrepareAndExecuteFilter.java:51)
at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:275)
at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:397)
at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:108)
at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:3800)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4450)
at org.apache.catalina.startup.HostConfig.checkResources(HostConfig.java:1173)
at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1271)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:296)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1337)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1601)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1610)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1590)
at java.lang.Thread.run(Thread.java:619)
Caused by: Unable to load configuration. - [unknown location]
at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:69)
at org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java:371)
at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:415)
... 16 more
Caused by: Caught exception while loading file struts-default.xml - [unknown location]
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadConfigurationFiles(XmlConfigurationProvider.java:913)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadDocuments(XmlConfigurationProvider.java:154)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.init(XmlConfigurationProvider.java:121)
at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:179)
at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:66)
... 18 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>(SAX2DOM.java:69)
at com.sun.org.apache.xalan.internal.xsltc.runtime.output.TransletOutputHandlerFactory.getSerializationHandler(TransletOutputHandlerFactory.java:187)
at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.getOutputHandler(TransformerImpl.java:392)
at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerHandlerImpl.setResult(TransformerHandlerImpl.java:137)
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:904)
... 22 more