异常：java.lang.NoClassDefFoundError:com/opensymphony/xwork2/util/TextUtils
原因：jsonplugin-0.34.jar 配合 struts2-core-2.1.8.1.jar使用的情况下报的异常，但以前的项目中jsonplugin-0.34.jar 配合 struts2-core-2.1.6.jar使用不会出现这样的异常
解决方法：去掉jsonplugin-0.34.jar，使用struts2-json-plugin-2.1.8.1.jar 和json-lib-2.1.jar，struts2-junit-plugin-2.1.8.jar三个包
还有在使用json格式传输数据的时候struts.xml配置的extends="struts-default"改成extends="json-default"，因为json-default已经extends了struts-default，此处可参看struts2-json-plugin-2.1.8.1.jar下面的struts-plugin.xml文件。如果此处不改的话会报错
严重: Exception starting filter struts2
Unable to load configuration. - action - file:/D:/Tomcat6.0/webapps/mydangdang/WEB-INF/classes/struts.xml:17:75
atorg.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:428)
atorg.apache.struts2.dispatcher.FilterDispatcher.init(FilterDispatcher.java:190)
atorg.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:275)
atorg.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:397)
atorg.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:108)
atorg.apache.catalina.core.StandardContext.filterStart(StandardContext.java:3693)
atorg.apache.catalina.core.StandardContext.start(StandardContext.java:4342)
atorg.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:761)
atorg.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:741)
atorg.apache.catalina.core.StandardHost.addChild(StandardHost.java:525)
atorg.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:920)
atorg.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:883)
atorg.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:492)
atorg.apache.catalina.startup.HostConfig.start(HostConfig.java:1138)
atorg.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:311)
atorg.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:120)
atorg.apache.catalina.core.ContainerBase.start(ContainerBase.java:1023)
atorg.apache.catalina.core.StandardHost.start(StandardHost.java:719)
atorg.apache.catalina.core.ContainerBase.start(ContainerBase.java:1015)
atorg.apache.catalina.core.StandardEngine.start(StandardEngine.java:443)
atorg.apache.catalina.core.StandardService.start(StandardService.java:448)
atorg.apache.catalina.core.StandardServer.start(StandardServer.java:710)
atorg.apache.catalina.startup.Catalina.start(Catalina.java:552)
atsun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
atsun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
atsun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
atjava.lang.reflect.Method.invoke(Method.java:597)
atorg.apache.catalina.startup.Bootstrap.start(Bootstrap.java:288)
atorg.apache.catalina.startup.Bootstrap.main(Bootstrap.java:413)
Caused by: Unable to load configuration. - action -file:/D:/Tomcat6.0/webapps/mydangdang/WEB-INF/classes/struts.xml:17:75
atcom.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:69)
atorg.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java:371)
atorg.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:415)
... 28 more
Caused by: Error building results for action valid innamespace - action - file:/D:/Tomcat6.0/webapps/mydangdang/WEB-INF/classes/struts.xml:17:75
atcom.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addAction(XmlConfigurationProvider.java:378)
atcom.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addPackage(XmlConfigurationProvider.java:479)
atcom.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadPackages(XmlConfigurationProvider.java:275)
atorg.apache.struts2.config.StrutsXmlConfigurationProvider.loadPackages(StrutsXmlConfigurationProvider.java:111)
atcom.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:204)
atcom.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:66)
... 30 more
Caused by: There is no result type defined for type 'json'mapped with name 'success'. Did you mean 'json'?- result - file:/D:/Tomcat6.0/webapps/mydangdang/WEB-INF/classes/struts.xml:18:42
atcom.opensymphony.xwork2.config.providers.XmlConfigurationProvider.buildResults(XmlConfigurationProvider.java:632)
atcom.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addAction(XmlConfigurationProvider.java:376)
... 35 more
