tomcat org.apache.jasper.JasperException: java.lang.NullPointerException

本文介绍了一种常见的JAR包冲突问题,即工程内部的JAR包与TOMCAT服务器自带的JAR包发生冲突的情况,并提供了解决方案:移除工程内部的javax.servlet.jsp.jar。

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原因:因为工程内的JAR包和TOMCAT内的JAR包起了冲空。

解决:去掉工程内的javax.selvert.jsp.jar就可以了

org.apache.jasper.JasperException: 在 [16] 行处理 [/registration_action.jsp] 时发生异常 13: String yonghuming = request.getParameter("username"); 14: String yonghumima = request.getParameter("password"); 15: Connection conn = DBUtil.getConnection(); 16: System.out.println(conn.isClosed()); 17: String sql = "INSERT INTO account(name, pass) VALUES(?, ?)"; 18: PreparedStatement pstmt = conn.prepareStatement(sql); 19: pstmt.setString(1, yonghuming); Stacktrace: org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:599) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:488) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:380) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:328) jakarta.servlet.http.HttpServlet.service(HttpServlet.java:658) org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51) 根本原因。 java.lang.NullPointerException: Cannot invoke "java.sql.Connection.isClosed()" because "conn" is null org.apache.jsp.registration_005faction_jsp._jspService(registration_005faction_jsp.java:142) org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) jakarta.servlet.http.HttpServlet.service(HttpServlet.java:658) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:456) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:380) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:328) jakarta.servlet.http.HttpServlet.service(HttpServlet.java:658) org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51
05-30
org.apache.jasper.JasperException: 在 [69] 行处理 [/teacher/teacher_teaching.jsp] 时发生异常 66: <th field="credit" formatter="getCredit">课程学分</th> 67: </tr> 68: <%String username = session.getAttribute("username").toString(); 69: teacheraction te=new teacheraction(username);ResultSet rs =te.getaresult(); while(rs.next()) { %> 70: <tr> 71: <td><%= rs.getString("semester") %></td> 72: <td><%= rs.getString("course_name") %></td> Stacktrace: org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:610) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:499) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:379) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:327) javax.servlet.http.HttpServlet.service(HttpServlet.java:779) org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) com.beacon.sms.filter.EncodingFilter.doFilter(EncodingFilter.java:27) 根本原因。 java.lang.NullPointerException org.apache.jsp.teacher.teacher_005fteaching_jsp._jspService(teacher_005fteaching_jsp.java:188) org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) javax.servlet.http.HttpServlet.service(HttpServlet.java:779) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:466) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:379) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:327) javax.servlet.http.HttpServlet.service(HttpServlet.java:779) org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) com.beacon.sms.filter.EncodingFilter.doFilter(EncodingFilter.java:27)
最新发布
06-13
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