strut2出现这样的错误，就解

Question

检查了，完全没有错误了
説明 The server encountered an internal error () that prevented it from fulfilling this request.例外Unable to instantiate Action, com.gu.action.user.LoginAction,  defined for 'a' in namespace '/user'null
com.opensymphony.xwork2.DefaultActionInvocation.createAction(DefaultActionInvocation.java:307)
com.opensymphony.xwork2.DefaultActionInvocation.init(DefaultActionInvocation.java:388)
com.opensymphony.xwork2.DefaultActionProxy.prepare(DefaultActionProxy.java:187)
org.apache.struts2.impl.StrutsActionProxy.prepare(StrutsActionProxy.java:61)
org.apache.struts2.impl.StrutsActionProxyFactory.createActionProxy(StrutsActionProxyFactory.java:39)
com.opensymphony.xwork2.DefaultActionProxyFactory.createActionProxy(DefaultActionProxyFactory.java:47)
org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:478)
org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91)原因java.lang.NullPointerException
java.lang.Class.forName0(Native Method)
java.lang.Class.forName(Class.java:169)
com.gu.util.Factory.getInstance(Factory.java:12)
com.gu.action.BaseAction.<init>(BaseAction.java:18)
com.gu.action.user.LoginAction.<init>(LoginAction.java:7)
sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
java.lang.reflect.Constructor.newInstance(Constructor.java:513)
java.lang.Class.newInstance0(Class.java:355)
java.lang.Class.newInstance(Class.java:308)
com.opensymphony.xwork2.ObjectFactory.buildBean(ObjectFactory.java:119)
com.opensymphony.xwork2.ObjectFactory.buildBean(ObjectFactory.java:150)
com.opensymphony.xwork2.ObjectFactory.buildBean(ObjectFactory.java:139)
com.opensymphony.xwork2.ObjectFactory.buildAction(ObjectFactory.java:109)
com.opensymphony.xwork2.DefaultActionInvocation.createAction(DefaultActionInvocation.java:288)
com.opensymphony.xwork2.DefaultActionInvocation.init(DefaultActionInvocation.java:388)
com.opensymphony.xwork2.DefaultActionProxy.prepare(DefaultActionProxy.java:187)
org.apache.struts2.impl.StrutsActionProxy.prepare(StrutsActionProxy.java:61)
org.apache.struts2.impl.StrutsActionProxyFactory.createActionProxy(StrutsActionProxyFactory.java:39)
com.opensymphony.xwork2.DefaultActionProxyFactory.createActionProxy(DefaultActionProxyFactory.java:47)
org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:478)
org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91)

Answer 1

1.没有加载struts2-spring-plugin-2.1.8.1.jar2.可能是包冲突，删除asm.jar3.struts或spring 配置文件错误
4.spring配置文件名错误，spring配置文件默认是applicationContext.xml,在web.xml中可能会配成<context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/applicationContext-*.xml,classpath*:applicationContext-*.xml</param-value>
 </context-param>