java.lang.NoClassDefFoundError orgapachecommonslangStringUtils

java.lang.NoClassDefFoundError: org/apache/commons/lang/StringUtils

at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.register(XmlConfigurationProvider.java:198)

at org.apache.struts2.config.StrutsXmlConfigurationProvider.register(StrutsXmlConfigurationProvider.java:101)

at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:180)

at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:66)

at org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java:380)

at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:424)

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:295)

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.lifecycleEvent(HostConfig.java:324)

at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:142)

at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1065)

at org.apache.catalina.core.StandardHost.start(StandardHost.java:840)

at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1057)

at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:463)

at org.apache.catalina.core.StandardService.start(StandardService.java:525)

at org.apache.catalina.core.StandardServer.start(StandardServer.java:754)

at org.apache.catalina.startup.Catalina.start(Catalina.java:595)

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:289)

at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414)
Caused by:
java.lang.ClassNotFoundException: org.apache.commons.lang.StringUtils

at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1680)

at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1526)

... 35 more

解决方案：
问题前：