今天練習Struts2，遇到了以下問題：
嚴重: Exception starting filter struts2
Unable to load configuration. - bean - jar:file:/E:/Program%20Files/Tomcat%206.0/webapps/struts2Test/WEB-INF/lib/struts2-core-2.2.3.1.jar!/struts-default.xml:29:72
at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:58)
at org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java:360)
at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:403)
at org.apache.struts2.dispatcher.ng.InitOperations.initDispatcher(InitOperations.java:69)
at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.init(StrutsPrepareAndExecuteFilter.java:48)
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:3709)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4363)
at org.apache.catalina.startup.HostConfig.checkResources(HostConfig.java:1116)
at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1214)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:293)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
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 bean: type: class:com.opensymphony.xwork2.ObjectFactory - bean - jar:file:/E:/Program%20Files/Tomcat%206.0/webapps/struts2Test/WEB-INF/lib/struts2-core-2.2.3.1.jar!/struts-default.xml:29:72
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.register(XmlConfigurationProvider.java:222)
at org.apache.struts2.config.StrutsXmlConfigurationProvider.register(StrutsXmlConfigurationProvider.java:101)
at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:165)
at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:55)
... 18 more
Caused by: Bean type class com.opensymphony.xwork2.ObjectFactory with the name xwork has already been loaded by bean - jar:file:/E:/Program%20Files/Tomcat%206.0/webapps/struts2Test/WEB-INF/lib/struts2-core-2.1.6.jar!/struts-default.xml:29:72 - bean - jar:file:/E:/Program%20Files/Tomcat%206.0/webapps/struts2Test/WEB-INF/lib/struts2-core-2.2.3.1.jar!/struts-default.xml:29:72
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.register(XmlConfigurationProvider.java:206)
... 21 more
2011-9-29 15:18:53 org.apache.catalina.core.StandardContext start
嚴重: Error filterStart
2011-9-29 15:18:53 org.apache.catalina.core.StandardContext start
嚴重: Context [/struts2Test] startup failed due to previous errors
解決方法：
1. 導入commons-io-1.3.2.jar和commons-fileupload-1.2.1.jar;
2. 導入Struts-spring-plugin-2.2.1.jar
3.改標籤屬性：<package name="default" extends="struts-default">修改成：<package name="login" extends="struts-default">
4. 導入Struts-spring-plugin-2.2.1.jar(是否使用Spring，沒用的話不導)
4.
5. 導入commons-io-1.3.2.jar和commons-fileupload-1.2.1.jar
6. 導入javassist-3.11.0.GA.jar
如果還解決不了，請用兩大神器：baidu,google.