首先，项目的基础代码是没有错误的！绝对没错，任何代码都保证没有错误，XML配置也没有问题，但是跑起来一直报http 500
1HTTP Status 500 - 2 3type Exception report 4 5message 6 7description The server encountered an internal error that prevented it from fulfilling this request. 8 9exception 10 11java.lang.NullPointerException 12 com.opensymphony.xwork2.ognl.SecurityMemberAccess.isPackageExcluded(SecurityMemberAccess.java:114) 13 com.opensymphony.xwork2.ognl.SecurityMemberAccess.isAccessible(SecurityMemberAccess.java:63) 14 ognl.OgnlRuntime.isMethodAccessible(OgnlRuntime.java:1880) 15 ognl.OgnlRuntime.callAppropriateMethod(OgnlRuntime.java:1225) 16 ognl.ObjectMethodAccessor.callMethod(ObjectMethodAccessor.java:68) 17 com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethodWithDebugInfo(XWorkMethodAccessor.java:117) 18 com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethod(XWorkMethodAccessor.java:108) 19 ognl.OgnlRuntime.callMethod(OgnlRuntime.java:1369) 20 ognl.ASTMethod.getValueBody(ASTMethod.java:90) 21 ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:212) 22 ognl.SimpleNode.getValue(SimpleNode.java:258) 23 ognl.Ognl.getValue(Ognl.java:494) 24 ognl.Ognl.getValue(Ognl.java:458) 25 com.opensymphony.xwork2.ognl.OgnlUtil$2.execute(OgnlUtil.java:309) 26 com.opensymphony.xwork2.ognl.OgnlUtil.compileAndExecute(OgnlUtil.java:340) 27 com.opensymphony.xwork2.ognl.OgnlUtil.getValue(OgnlUtil.java:307) 28 com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:423) 29 com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:287) 30 com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:250) 31 org.apache.struts2.interceptor.DeprecationInterceptor.intercept(DeprecationInterceptor.java:41) 32 com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) 33 org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:256) 34 com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) 35 com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:167) 36 com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) 37 com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) 38 com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:265) 39 org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:76) 40 com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) 41 com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) 42 com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:138) 43 com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) 44 com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:229) 45 com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) 46 com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) 47 com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:229) 48 com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) 49 com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) 50 com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:191) 51 com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) 52 org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:73) 53 com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) 54 org.apache.struts2.interceptor.DateTextFieldInterceptor.intercept(DateTextFieldInterceptor.java:125) 55 com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) 56 org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:91) 57 com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) 58 org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:253) 59 com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) 60 com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100) 61 com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) 62 com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141) 63 com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) 64 com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:145) 65 com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) 66 com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:171) 67 com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) 68 com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) 69 com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:139) 70 com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) 71 org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164) 72 com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) 73 com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:193) 74 com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) 75 com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:189) 76 com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) 77 org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54) 78 org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:564) 79 org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:81) 80 org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:99) 81note The full stack trace of the root cause is available in the Apache Tomcat/8.0.38 logs. 82 83Apache Tomcat/8.0.38
然后更种调试各种修改！ 后来终于找到问题的所在！那就是：
Action类放到了默认的根目录下！
###Action类放到了默认的根目录下！ ###Action类放到了默认的根目录下！ 如下图 
解决方法： 随便建一个包，把Action类放到自定义包里，就解决了！估计是struts2无法加载默认包里的Action类吧！！