想问怎么解决
HTTP Status 500 – Internal Server Error
Type 异常报告
消息 在 [78] 行处理 [/pages/stuList.jsp] 时发生异常
描述 服务器遇到一个意外的情况，阻止它完成请求。
Exception
org.apache.jasper.JasperException: 在 [78] 行处理 [/pages/stuList.jsp] 时发生异常
75: StudentService stuService = new StudentServiceimp();
76: GradeService gradeService = new GradeServiceimp();
77: Grade grade = new Grade();
78: List list = stuService.getAllStudent();
79: session.setAttribute("list", list);
80:
81: %>
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:625)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:514)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:385)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:329)
javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
cn.filter.LoginFillter.doFilter(LoginFillter.java:37)
cn.filter.CharEncodingFilter.doFilter(CharEncodingFilter.java:33)
Root Cause
java.lang.NullPointerException
cn.dao.impl.StudentDaoimp.getAllStudent(StudentDaoimp.java:28)
cn.service.impl.StudentServiceimp.getAllStudent(StudentServiceimp.java:26)
org.apache.jsp.pages.stuList_jsp._jspService(stuList_jsp.java:200)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:476)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:385)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:329)
javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
cn.filter.LoginFillter.doFilter(LoginFillter.java:37)
cn.filter.CharEncodingFilter.doFilter(CharEncodingFilter.java:33)
