HTTP Status 500 - An exception occurred processing JSP page /Courselist.jsp at l

柠檬茶好喝 2018-06-08 11:29:47

报错页面
HTTP Status 500 - An exception occurred processing JSP page /Courselist.jsp at at line 48
type Exception report

message An exception occurred processing JSP page /Courselist.jsp at line 48

description The server encountered an internal error that prevented it from fulfilling this request.

exception
org.apache.jasper.JasperException: An exception occurred processing JSP page /Courselist.jsp at line 48

45: </tr>
46:
47: <%
48: for(int i=0;i<course.size();i++){
49: Course c = course.get(i);
50: %>
51: <tr>

Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:579)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:476)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

root cause
java.lang.NullPointerException
org.apache.jsp.Courselist_jsp._jspService(Courselist_jsp.java:172)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:438)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

note The full stack trace of the root cause is available in the Apache Tomcat/8.0.41 logs.

jsp页面如下：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<%@ page import="com.zsn.dao.CourseDao,com.zsn.dao.impl.CourseDaoImpl,com.zsn.model1.Course" %>
<%@ page import = "java.util.List" %>

<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">

<title>My JSP 'Courselist.jsp' starting page</title>

<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">


</head>

<body>

<%
CourseDao dao = new CourseDaoImpl();
List<Course> course = dao.findAll();
%>

<div>
<table border = "1" width=550px align="center">
<caption>课程管理信息表</caption>
<tr>
<th width=100px align="center">编号</th>
<th width=350px align="center">课程名</th>
<th align="center">操作方式</th>
</tr>

<%
for(int i=0;i<course.size();i++){
Course c = course.get(i);
%>
<tr>
<td align="center"><%=c.getId() %></td>
<td align="center"><%=c.getCoursename() %></td>
<td>
<a href= "Courseupdate.jsp?id=<%=c.getId()%>" >修改</a>
<a href= "Coursedelete_handler.jsp?id=<%=c.getId()%>">删除</a>
</td>
</tr>
<%
}
%>
</table>
</div>
<div align="center"><a href = "Coursenew.jsp">添加章节</a></div>
<div align="center"><a href = "HouTaiKeCheng.jsp">返回课程管理</a></div>
</body>
</html>

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