成功解决SSH框架java.lang.NullPointerException报空指针

本文主要是介绍成功解决SSH框架java.lang.NullPointerException报空指针，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

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前言

仅作为学习笔记，供大家参考
总结的不错的话，记得点赞收藏关注哦！

今天用SSH框架遇到一个低级的错误浪费了很长时间，特此记录一下！

java.lang.NullPointerExceptionat cn.bdqn.service.impl.StuServcieImpl.selectAll(StuServcieImpl.java:25)at cn.bdqn.action.stuAction.selectAll(stuAction.java:26)at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)at java.lang.reflect.Method.invoke(Unknown Source)at com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:450)at com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:289)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:252)at org.apache.struts2.interceptor.DeprecationInterceptor.intercept(DeprecationInterceptor.java:41)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:256)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:167)at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:265)at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:138)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:254)at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:254)at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:191)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)at org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:73)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:91)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)at org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:252)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:145)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)at com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:171)at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)at com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:139)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)at com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:193)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:189)at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54)at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:562)at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:99)at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:503)at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:314)at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)at java.lang.Thread.run(Unknown Source)