今天做了一个struts2的登录小例子，在tomcat启动的时候报了下面错误
严重: Exception starting filter struts2
javax.xml.transform.TransformerFactoryConfigurationError: Provider org.apache.xalan.processor.TransformerFactoryImpl not found
at javax.xml.transform.TransformerFactory.newInstance(TransformerFactory.java:108)
at com.opensymphony.xwork2.util.DomHelper$DOMBuilder.(DomHelper.java:159)
at com.opensymphony.xwork2.util.DomHelper.parse(DomHelper.java:107)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadConfigurationFiles(XmlConfigurationProvider.java:904)
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)
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.FilterDispatcher.init(FilterDispatcher.java:190)
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.(ApplicationFilterConfig.java:108)
at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:3709)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4363)
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:926)
at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:889)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:492)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1149)
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:578)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:288)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:413)
2011-3-18 16:37:10 org.apache.catalina.core.StandardContext start
严重: Error filterStart
2011-3-18 16:37:10 org.apache.catalina.core.StandardContext start
严重: Context [/struts2Demo] startup failed due to previous errors
2011-3-18 16:37:10 org.apache.coyote.http11.Http11Protocol start
信息: Starting Coyote HTTP/1.1 on http-8080
2011-3-18 16:37:10 org.apache.jk.common.ChannelSocket init
信息: JK: ajp13 listening on /0.0.0.0:8009
2011-3-18 16:37:10 org.apache.jk.server.JkMain start
信息: Jk running ID=0 time=0/40 config=null
2011-3-18 16:37:10 org.apache.catalina.startup.Catalina start
信息: Server startup in 29318 ms
搜索了相关解决方法，添加了xalan.jar，可是重新启动tomcat还是报这个错误。
我的环境是tomcat6.0+jdk1.6。
麻烦大家帮忙解决下~~谢谢~~
