求助一个struts2+tomcat的问题，百思不得其解啊
tomcat信息：
2012-4-11 19:43:58 org.apache.catalina.core.AprLifecycleListener init
信息: An older version 1.1.17 of the APR based Apache Tomcat Native library is installed, while Tomcat recommends version greater than 1.1.22
2012-4-11 19:43:58 org.apache.catalina.core.AprLifecycleListener init
信息: Loaded APR based Apache Tomcat Native library 1.1.17.
2012-4-11 19:43:58 org.apache.catalina.core.AprLifecycleListener init
信息: APR capabilities: IPv6 [true], sendfile [true], accept filters [false], random [true].
2012-4-11 19:43:59 org.apache.coyote.http11.Http11AprProtocol init
信息: Initializing Coyote HTTP/1.1 on http-8080
2012-4-11 19:43:59 org.apache.coyote.ajp.AjpAprProtocol init
信息: Initializing Coyote AJP/1.3 on ajp-8009
2012-4-11 19:43:59 org.apache.catalina.startup.Catalina load
信息: Initialization processed in 1086 ms
2012-4-11 19:43:59 org.apache.catalina.core.StandardService start
信息: Starting service Catalina
2012-4-11 19:43:59 org.apache.catalina.core.StandardEngine start
信息: Starting Servlet Engine: Apache Tomcat/6.0.35
2012-4-11 19:43:59 org.apache.catalina.startup.HostConfig deployDescriptor
信息: Deploying configuration descriptor host-manager.xml
2012-4-11 19:43:59 org.apache.catalina.startup.HostConfig deployDescriptor
信息: Deploying configuration descriptor manager.xml
2012-4-11 19:43:59 org.apache.catalina.startup.HostConfig deployDirectory
信息: Deploying web application directory docs
2012-4-11 19:43:59 org.apache.catalina.startup.HostConfig deployDirectory
信息: Deploying web application directory examples
2012-4-11 19:44:00 org.apache.catalina.core.ApplicationContext log
信息: ContextListener: contextInitialized()
2012-4-11 19:44:00 org.apache.catalina.core.ApplicationContext log
信息: SessionListener: contextInitialized()
2012-4-11 19:44:00 org.apache.catalina.startup.HostConfig deployDirectory
信息: Deploying web application directory ROOT
2012-4-11 19:44:00 org.apache.catalina.startup.HostConfig deployDirectory
信息: Deploying web application directory Test
2012-4-11 19:44:00 org.apache.catalina.core.StandardContext filterStart
严重: Exception starting filter struts2
java.lang.ClassNotFoundException: org.apache.struts2.dispatcher.FilterDispatcher
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1680)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1526)
at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:269)
at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:422)
at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:115)
at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4072)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4726)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:799)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:779)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:601)
at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1079)
at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:1002)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:506)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1317)
at org.apache.catalina.startup.HostConfig.lifecycle