javaweb程序一登陆就出错，无法跳转到另一个页面

Question

全是错误报告，不知道哪里出来问题，登陆之后应该跳转到下一个页面的结果也没有跳转，刚学要写课设，级求大神解决

严重: Servlet.service() for servlet jsp threw exception
java.lang.NullPointerException
at org.apache.jsp.admin_jsp._jspService(admin_jsp.java:156)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
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 javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at filter.EncodingFilter2.doFilter(EncodingFilter2.java:39)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:716)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:466)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:391)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:318)
at servlet.Login.doGet(Login.java:36)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at filter.EncodingFilter2.doFilter(EncodingFilter2.java:39)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:94)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:620)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:502)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1132)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:684)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2527)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2516)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
org.apache.jasper.JasperException: An exception occurred processing JSP page /admin.jsp at line 35

32: %>
33: <br> 34: function confirmapply(){<br> 35: document.getElementById(&quot;showFrame&quot;).src=&quot;confirm.jsp?dno=&lt;%=worker.getDno()%&gt;&amp;eno=&lt;%=worker.getEno()%&gt;&quot;;<br> 36: }<br> 37: function dnoworker(){<br> 38: document.getElementById(&quot;showFrame&quot;).src=&quot;dnoworkers.jsp?dno=&lt;%=worker.getDno()%&gt;&quot;;</p> <p>Stacktrace:<br> at org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:579)<br> at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:476)<br> at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)<br> at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)<br> at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)<br> at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292)<br> at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)<br> at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)<br> at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)<br> at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)<br> at filter.EncodingFilter2.doFilter(EncodingFilter2.java:39)<br> at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)<br> at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)<br> at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:716)<br> at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:466)<br> at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:391)<br> at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:318)<br> at servlet.Login.doGet(Login.java:36)<br> at javax.servlet.http.HttpServlet.service(HttpServlet.java:622)<br> at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)<br> at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292)<br> at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)<br> at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)<br> at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)<br> at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)<br> at filter.EncodingFilter2.doFilter(EncodingFilter2.java:39)<br> at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)<br> at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)<br> at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)<br> at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:94)<br> at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504)<br> at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)<br> at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)<br> at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:620)<br> at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)<br> at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:502)<br> at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1132)<br> at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:684)<br> at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2527)<br> at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2516)<br> at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)<br> at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)<br> at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)<br> at java.lang.Thread.run(Thread.java:745)<br> Caused by: java.lang.NullPointerException<br> at org.apache.jsp.admin_jsp._jspService(admin_jsp.java:156)<br> at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)<br> at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)<br> at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:438)<br> ... 42 more</p>

Answer 1

java.lang.NullPointerException空指针问题从错误报告自上到下找到你自己写的类就可以找到错误