急求请大侠帮忙呀！！！
这是数据处理层代码：
<%--
Document : loginCheck
Created on : 2013-11-16, 13:50:28
Author : Administrator
--%>
<%@page import="java.sql.*"%>%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>数据处理页面</title>
</head>
<body>
<%
String userName =new String(request.getParameter("UserName").getBytes("ISO-8859-1"),"UTF-8");
String password =new String(request.getParameter("UserPwd").getBytes("ISO-8859-1"),"UTF-8");
Connection con = null;
Statement st = null;
ResultSet rs = null;
if(userName.equals("")) {
response.sendRedirect("http://localhost:8084/MYWEB/Login/login.jsp");
}
try{
Class.forName("com.mysql.jdbc.Driver").newInstance();
/*url后面加的?useUnicode=true&characterEncoding=gbk，是为了处理向数据库中添加数据时出现乱码的问题。*/
String url="jdbc:mysql://localhost:3306/bbs?useUnicode=true&characterEncoding=gbk";
//String url="jdbc:mysql://localhost:3306/eims?user=root&&password=root";
con=DriverManager.getConnection(url,"root","213124");
st=con.createStatement();
String query="select * from Tb_user where UserName='" + userName + "'";
rs=st.executeQuery(query);
if(rs.next()){
String query2 ="select * from Tb_user where UserPwd='" + password + "'";
rs=st.executeQuery(query2);
if(rs.next()){
response.sendRedirect("http://localhost:8084/MYWEB/main/lookMessage.jsp");
}else{
response.sendRedirect("http://localhost:8084/MYWEB/Login/login.jsp");
}
}
}catch(Exception e){
e.printStackTrace();
}finally{
rs.close();
st.close();
con.close();
}
%>
</body>
</html>
出现错误：
HTTP Status 500 - java.lang.NullPointerException
--------------------------------------------------------------------------------
type Exception report
message java.lang.NullPointerException
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:549)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:470)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
root cause
java.lang.NullPointerException
org.apache.jsp.Login.loginCheck_jsp._jspService(loginCheck_jsp.java:76)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
note The full stack trace of the root cause is available in the Apache Tomcat/7.0.41 logs.
--------------------------------------------------------------------------------
Apache Tomcat/7.0.41
该怎么搞？？？？
[解决办法]
到tomcat的works目录下找到loginCheck_jsp.java这个类,看下第76行的代码,就应该可以知道是哪个为null了
[解决办法]
