struts中使用json，報錯There is no result type defined for type 'json' mapped with name 'success'.

Unable to load configuration. - action - file:/E:/eclipseCode/.metadata/.plugins/org.eclipse.wst.server.core/tmp2/wtpwebapps/ZXBServer12.13/WEB-INF/classes/config/struts_invoiceInfo.xml:24:23
	at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:450)
	at org.apache.struts2.dispatcher.ng.InitOperations.initDispatcher(InitOperations.java:74)
	at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.init(StrutsPrepareAndExecuteFilter.java:51)
	at com.sykj.filter.StrutsFilter.init(StrutsFilter.java:40)
	at org.apache.catalina.core.ApplicationFilterConfig.initFilter(ApplicationFilterConfig.java:279)
	at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:260)
	at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:105)
	at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4908)
	at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5602)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1572)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1562)
	at java.util.concurrent.FutureTask.run(FutureTask.java:262)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:745)
Caused by: Unable to load configuration. - action - file:/E:/eclipseCode/.metadata/.plugins/org.eclipse.wst.server.core/tmp2/wtpwebapps/ZXBServer12.13/WEB-INF/classes/config/struts_invoiceInfo.xml:24:23
	at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:69)
	at org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java:390)
	at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:437)
	... 15 more
Caused by: Error building results for action deleteInv in namespace /invoice - action - file:/E:/eclipseCode/.metadata/.plugins/org.eclipse.wst.server.core/tmp2/wtpwebapps/ZXBServer12.13/WEB-INF/classes/config/struts_invoiceInfo.xml:24:23
	at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addAction(XmlConfigurationProvider.java:389)
	at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addPackage(XmlConfigurationProvider.java:495)
	at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadPackages(XmlConfigurationProvider.java:286)
	at org.apache.struts2.config.StrutsXmlConfigurationProvider.loadPackages(StrutsXmlConfigurationProvider.java:112)
	at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:234)
	at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:66)
	... 17 more
Caused by: There is no result type defined for type 'json' mapped with name 'success'.  Did you mean 'json'? - result - file:/E:/eclipseCode/.metadata/.plugins/org.eclipse.wst.server.core/tmp2/wtpwebapps/ZXBServer12.13/WEB-INF/classes/config/struts_invoiceInfo.xml:25:39
	at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.buildResults(XmlConfigurationProvider.java:653)
	at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addAction(XmlConfigurationProvider.java:387)
	... 22 more

這個錯誤是json初學者很容易遇到的錯誤：現在把本人學習過程中遇到的問題跟大家分享一下，歡迎拍磚

1、首先查看Jar有沒有少

commons-beanutils-1.7.0.jar
commons-collections-3.2.jar
commons-lang-2.3.jar
commons-logging-1.1.jar
ezmorph-1.0.4.jar
json-lib-2.2.3-jdk15.jar
jsonplugin-0.33.jar
另外struts2-json-plugin-2.2.1.1.jar 和 jsonplugin-0.33.jar會衝突不能同時存在

2、看Struts配置文件的繼承部分對不對，

 <package name="reg" namespace="/reg" extends="struts-default,json-default">

json-default是必須的