请问这个404错误 是什么原因 谢谢

严重: Dispatcher initialization failed
Unable to load configuration. - action - file:/D:/Program%20Files/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/Struts_Study/WEB-INF/classes/struts.xml:9:62
	at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:70)
	at org.apache.struts2.dispatcher.Dispatcher.getContainer(Dispatcher.java:967)
	at org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java:435)
	at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:479)
	at org.apache.struts2.dispatcher.ng.InitOperations.initDispatcher(InitOperations.java:74)
	at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.init(StrutsPrepareAndExecuteFilter.java:57)
	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:4660)
	at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5298)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1407)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1397)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)
Caused by: Action class [action.HelloWorldAction] not found - action - file:/D:/Program%20Files/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/Struts_Study/WEB-INF/classes/struts.xml:9:62
	at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.verifyAction(XmlConfigurationProvider.java:486)
	at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addAction(XmlConfigurationProvider.java:429)
	at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addPackage(XmlConfigurationProvider.java:556)
	at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadPackages(XmlConfigurationProvider.java:295)
	at org.apache.struts2.config.StrutsXmlConfigurationProvider.loadPackages(StrutsXmlConfigurationProvider.java:112)
	at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:264)
	at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:67)
	... 17 more

六月 15, 2016 11:26:28 下午 org.apache.catalina.core.StandardContext filterStart
严重: Exception starting filter struts2
Unable to load configuration. - action - file:/D:/Program%20Files/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/Struts_Study/WEB-INF/classes/struts.xml:9:62
	at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:493)
	at org.apache.struts2.dispatcher.ng.InitOperations.initDispatcher(InitOperations.java:74)
	at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.init(StrutsPrepareAndExecuteFilter.java:57)
	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:4660)
	at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5298)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1407)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1397)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)
Caused by: Unable to load configuration. - action - file:/D:/Program%20Files/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/Struts_Study/WEB-INF/classes/struts.xml:9:62
	at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:70)
	at org.apache.struts2.dispatcher.Dispatcher.getContainer(Dispatcher.java:967)
	at org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java:435)
	at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:479)
	... 14 more
Caused by: Action class [action.HelloWorldAction] not found - action - file:/D:/Program%20Files/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/Struts_Study/WEB-INF/classes/struts.xml:9:62
	at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.verifyAction(XmlConfigurationProvider.java:486)
	at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addAction(XmlConfigurationProvider.java:429)
	at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addPackage(XmlConfigurationProvider.java:556)
	at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadPackages(XmlConfigurationProvider.java:295)
	at org.apache.struts2.config.StrutsXmlConfigurationProvider.loadPackages(StrutsXmlConfigurationProvider.java:112)
	at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:264)
	at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:67)
	... 17 more