请尝试以下操作：
1、尝试按F5进行页面刷新
2、重新键入URL地址进入访问
java.lang.NullPointerException
com.inxedu.os.edu.controller.course.CourseController.couinfo(CourseController.java:236)
sun.reflect.GeneratedMethodAccessor1250.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:220)
org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:134)
org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:116)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738)
org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
javax.servlet.http.HttpServlet.service(HttpServlet.java:489)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
javax.servlet.http.HttpServlet.service(HttpServlet.java:583)
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:212)
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:181)
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156)
com.opensymphony.sitemesh.webapp.SiteMeshFilter.obtainContent(SiteMeshFilter.java:129)
com.opensymphony.sitemesh.webapp.SiteMeshFilter.doFilter(SiteMeshFilter.java:77)
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:181)
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156)
org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:181)
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156)
com.inxedu.os.common.session.MemcachedSessionFilter.doFilter(MemcachedSessionFilter.java:46)
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:181)
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156)
com.inxedu.os.common.session.XssFilter.doFilter(XssFilter.java:17)
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:181)
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156)
com.inxedu.os.common.session.BlackipFilter.doFilter(BlackipFilter.java:36)
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:181)
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156)
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:168)
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:90)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:483)
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:130)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:93)
org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:679)
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:346)
org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:617)
org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63)
org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:934)
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1698)
org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52)
org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:63)
java.lang.Thread.run(Unknown Source)
