SSH框架中点击登录出现的错误：java.lang.reflect.InvocationTargetException

做了个SSH框架的web项目，点击登录后网页中出现了下面的错误：HTTP Status 500 

直接上错误代码：

java.lang.reflect.InvocationTargetExceptionsun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)java.lang.reflect.Method.invoke(Method.java:597)com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:440)com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:279)com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242)com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:163)com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:249)org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:122)com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:148)com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:93)com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:235)com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:89)com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:128)com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)org.apache.struts2.interceptor.ProfilingActivationInterceptor.intercept(ProfilingActivationInterceptor.java:104)com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:267)com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:126)com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:138)com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:148)com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:128)com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:176)com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:52)org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:468)org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:76)

在网上找了好多解决方法，有的说是配置文件有错，反正千奇百怪的说法都有，最终我在网上找到了我这个问题的症结所在，原来是我的AdminServiceImpl文件中的loginAdmin方法里面错了，写成了return this.loginAdmin(admin); 其实应该为：return this.adminDAO.loginAdmin(admin);

一定要注意上面一行红色的字，就是少了adminDAO这个对象调用loginAdmin，才出现了上面的错误。