--------------------------------------------------------------------------------type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception org.apache.jasper.JasperException: java.lang.NullPointerException
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:522)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:416)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
root cause java.lang.NullPointerException
org.apache.jsp.outexam_jsp._jspService(outexam_jsp.java:153)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.20 logs.几个页面老是出现这种问题了 救命啊 我不是常上csdn 高手能否加我qq 791340493
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:522)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:416)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
root cause java.lang.NullPointerException
org.apache.jsp.outexam_jsp._jspService(outexam_jsp.java:153)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.20 logs.几个页面老是出现这种问题了 救命啊 我不是常上csdn 高手能否加我qq 791340493
空值被使用,要把你的JSP贴上来看看
<%@ page import="com.lizhe.*"%>
<%@ page import="java.sql.*"%>
<%@ page import="javax.sql.*"%><html>
<head>
<title>在线考试系统</title> <style type="text/css">
<!--
body,td,th {
font-size: 9pt;
}
-->
</style>
</head>
<body>
<form name="form1" method="post" action="simpleoutsave.jsp">
<table width="100%" border="0" cellspacing="0" cellpadding="0">
<tr>
<td width='20%'><%@ include file = "left.jsp" %></td>
<td width='80%'>
<br>
<br>
<table width="100%" border="0" cellspacing="1" cellpadding="1" bgColor=#595959>
<tr>
<td height="25" colspan="2" bgcolor="#FFFFFF">在线考试系统-选择考试</td>
</tr>
<tr bgColor=#d1face>
<td width="17%" height="25" >选择试卷编号:</td>
<td width="83%"><select name="papertitle" id="papertitle">
<%
DBConnectionManage db = new DBConnectionManage();
Connection conn = db.getFreeConnection();
String query = "select * from paper";
Statement st = null;
ResultSet rs = null;
try{
st = conn.createStatement();
rs = st.executeQuery(query);
while(rs.next()){
out.println("<option value='"+rs.getString("papertitle")+"'>"+rs.getString("papertitle")+"</option>");
}
}catch(Exception ex){
}finally{
st.close();
rs.close();
conn.close();
}
%>
</select></td>
</tr>
<tr bgcolor="#FFFFFF">
<td colspan="2" align="center"><input type="submit" name="Submit" value="提交">
<input type="reset" name="Submit2" value="重置"></td>
</tr>
</table></td>
</tr>
</table>
</form>
</body>
</html>
这是outexam.jsp的代码
要放到try{}里面去,catch(){这里打印一下错误信息}另外,所有的JSP,服务器都会先将其翻译成JAVA文件,并暂存到硬盘中
比如tomcat,会在“work”目录生成其对应的JAVA文件
你可以在你的工程里搜索下“outexam_jsp.java”文件,该文件153行是出错的地方
org.apache.jsp.outexam_jsp._jspService(outexam_jsp.java:153)
请确保你所使用的变量非Null
在tomcat/work/目录下找到outexam_jsp.java这个Servlet文件。
找到153行看是什么,这样,就可以找到是吧里出异常了!
但我认为有可能是conn为null
Connection conn = db.getFreeConnection();
String query = "select * from paper";
Statement st = null;
ResultSet rs = null;
try{
st = conn.createStatement();
rs = st.executeQuery(query);
while(rs.next()){
out.println("<option value='"+rs.getString("papertitle")+"'>"+rs.getString("papertitle")+"</option>");
}
}catch(Exception ex){
}finally{
st.close();
rs.close();
conn.close();
}
里面的st.close()错误了 可是想不明白怎么错了 求大家帮我看看
rs.close();
st.close();
conn.close();