Serious: in the context of path for [/StudentManagerWeb], the servlet/LoginServlet servlet. The service () throw exceptions
Java. Lang. NullPointerException
At com. Ischoolbar. Programmer. Servlet. LoginServlet. DoPost (LoginServlet. Java: 42)
The at javax.mail. Servlet. HTTP. HttpServlet. Service (HttpServlet. Java: 652)
The at javax.mail. Servlet. HTTP. HttpServlet. Service (HttpServlet. Java: 733)
The at org. Apache. Catalina. Core. ApplicationFilterChain. InternalDoFilter (ApplicationFilterChain. Java: 231)
The at org. Apache. Catalina. Core. ApplicationFilterChain. DoFilter (ApplicationFilterChain. Java: 166)
At org, apache tomcat, websocket server WsFilter. DoFilter (WsFilter. Java: 52)
The at org. Apache. Catalina. Core. ApplicationFilterChain. InternalDoFilter (ApplicationFilterChain. Java: 193)
The at org. Apache. Catalina. Core. ApplicationFilterChain. DoFilter (ApplicationFilterChain. Java: 166)
The at org. Apache. Catalina. Core. StandardWrapperValve. Invoke (StandardWrapperValve. Java: 199)
The at org. Apache. Catalina. Core. StandardContextValve. Invoke (StandardContextValve. Java: 97)
The at org. Apache. Catalina. The authenticator. AuthenticatorBase. Invoke (AuthenticatorBase. Java: 544)
The at org. Apache. Catalina. Core. StandardHostValve. Invoke (StandardHostValve. Java: 143)
The at org. Apache. Catalina. Valves. ErrorReportValve. Invoke (ErrorReportValve. Java: 81)
The at org. Apache. Catalina. Valves. AbstractAccessLogValve. Invoke (AbstractAccessLogValve. Java: 690)
The at org. Apache. Catalina. Core. StandardEngineValve. Invoke (StandardEngineValve. Java: 78)
At org. Apache. Catalina. Connector. CoyoteAdapter. Service (343) CoyoteAdapter. Java:
At org. Apache. Coyote. Http11. Http11Processor. Service (616) Http11Processor. Java:
The at org. Apache. Coyote. AbstractProcessorLight. Process (AbstractProcessorLight. Java: 65)
The at org. Apache. Coyote. AbstractProtocol $ConnectionHandler. Process (AbstractProtocol. Java: 831)
At org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun NioEndpoint. Java: (1634)
The at org.apache.tomcat.util.net.SocketProcessorBase.run (SocketProcessorBase. Java: 49)
The at Java. Util. Concurrent. ThreadPoolExecutor. RunWorker (ThreadPoolExecutor. Java: 1149)
The at Java. Util. Concurrent. ThreadPoolExecutor $Worker. The run (ThreadPoolExecutor. Java: 624)
At org, apache tomcat. Util. Threads. TaskThread $WrappingRunnable. Run (61) TaskThread. Java:
The at Java. Lang. Thread. The run (Thread. Java: 748)

After the login page can not jump, and then display the error

CodePudding user response:

Prompt information is so accurate, that you put the code to see bai,

Com. Ischoolbar. Programmer. Servlet. LoginServlet. DoPost 42 lines, null pointer exception

This exception information already very clear,

CodePudding user response:

reference 1st floor rumlee response:

prompt information is so accurate, that you put the code to see bai,

Com. Ischoolbar. Programmer. Servlet. LoginServlet. DoPost 42 lines, null pointer exception

This exception information already very clear,

String loginCpacha=request. GetSession (). The getAttribute (" loginCapcha "). The toString ();