springMVC+mybatis页面跳转为空，后台报错，这是什么问题？

Question

Caused by: 

java.lang.NullPointerException

at org.apache.jsp.WEB_002dINF.views.error._500_jsp._jspService(_500_jsp.java:132)

at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)

at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:438)

at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)

at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)

at org.eclipse.jetty.jsp.JettyJspServlet.service(JettyJspServlet.java:107)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)

at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:812)

at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:587)

at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)

at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:595)

at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:223)

at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1127)

at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:515)

at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185)

at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1061)

at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)

at org.eclipse.jetty.server.Dispatcher.forward(Dispatcher.java:191)

at org.eclipse.jetty.server.Dispatcher.error(Dispatcher.java:77)

at org.eclipse.jetty.server.handler.ErrorHandler.handle(ErrorHandler.java:92)

at org.eclipse.jetty.server.Response.sendError(Response.java:597)

at javax.servlet.http.HttpServletResponseWrapper.sendError(HttpServletResponseWrapper.java:158)

at org.sitemesh.webapp.contentfilter.HttpServletResponseBuffer.sendError(HttpServletResponseBuffer.java:261)

at org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver.handleMissingPathVariable(DefaultHandlerExceptionResolver.java:277)

at org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver.doResolveException(DefaultHandlerExceptionResolver.java:125)

at org.springframework.web.servlet.handler.AbstractHandlerExceptionResolver.resolveException(AbstractHandlerExceptionResolver.java:137)

at org.springframework.web.servlet.DispatcherServlet.processHandlerException(DispatcherServlet.java:1185)

at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1022)

at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:973)

at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:895)

at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:967)

at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:858)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:687)

at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:843)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)

at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:812)

at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1669)

at org.sitemesh.webapp.contentfilter.ContentBufferingFilter.bufferAndPostProcess(ContentBufferingFilter.java:169)

at org.sitemesh.webapp.contentfilter.ContentBufferingFilter.doFilter(ContentBufferingFilter.java:126)

at org.sitemesh.webapp.SiteMeshFilter.doFilter(SiteMeshFilter.java:120)

at org.sitemesh.config.ConfigurableSiteMeshFilter.doFilter(ConfigurableSiteMeshFilter.java:163)

at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)

at org.apache.shiro.web.servlet.AbstractShiroFilter.executeChain(AbstractShiroFilter.java:449)

at org.apache.shiro.web.servlet.AbstractShiroFilter$1.call(AbstractShiroFilter.java:365)

at org.apache.shiro.subject.support.SubjectCallable.doCall(SubjectCallable.java:90)

at org.apache.shiro.subject.support.SubjectCallable.call(SubjectCallable.java:83)

at org.apache.shiro.subject.support.DelegatingSubject.execute(DelegatingSubject.java:383)

at org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:362)

at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)

at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)

at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:262)

at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)

at org.springframework.orm.jpa.support.OpenEntityManagerInViewFilter.doFilterInternal(OpenEntityManagerInViewFilter.java:178)

at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)

at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)

at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:121)

at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)

at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)

at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:585)

at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)

at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:577)

at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:223)

at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1127)

at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:515)

at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185)

at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1061)

at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)

at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:215)

at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:110)

at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:97)

at org.eclipse.jetty.server.Server.handle(Server.java:499)

at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:311)

at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:257)

at org.eclipse.jetty.io.AbstractConnection$2.run(AbstractConnection.java:544)

at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:635)

at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:555)

at java.lang.Thread.run(Thread.java:745)

Answer 1

报了空指针异常，建议用debug模式跑一下，看看什么是空，然后做修改。