用户登陆的问题,用户名和密码正确可以通过,错误显示java.lang.NullPointerException
<%@ page contentType="text/html;charset=gb2312" language="java" import="java.sql.*,neweast.*,java.net.*"%>
<script language=JavaScript>
function backward(){
history.back();
}
</script>
<%if((String)session.getValue("username")=="XYJ"){
String name=request.getParameter("name").trim();
String pwd=request.getParameter("pwd").trim();
String guestip="";//定义访问者ip
/*out.print("session"+(String)session.getValue("username"));
out.print(name);
out.print(pwd);
out.print("<br>");
out.print(request.getRemoteAddr());*/
guestip=request.getRemoteAddr();//得到主机的ip
DataAccess bean=new DataAccess();
ResultSet rs=null,rs1=null;
String sql=" ";
int usr_grade,userid;
String sql1="select * from pubuser where username='"+name+"' and password='"+pwd+"'";
rs1=bean.executeQuery(sql1);
if(rs1.next()){
if(rs1.getInt("limituserip")==0){//未限定ip地址
sql="select * from pubuser where username='"+name+"' and password='"+pwd+"'";
} else {
sql="select * from pubuser where username='"+name+"' and password='"+pwd+"' and userip='"+guestip+"'";
}}else{
out.print("fail");
}
rs=bean.executeQuery(sql);
if(rs.next()&&rs.getInt("usercheck")==1&&rs.getInt("userok")==1){
out.print(rs.getString("username"));
usr_grade=rs.getInt("usergroup");
userid=rs.getInt("userid");
session.setAttribute("user_name" , name);
//session.setAttribute("user_id" , userid);
//session.setAttribute("user_group" , usr_grade);
response.sendRedirect("defau1.htm");
}
%>
<%}else{
out.print("<script language='javascript'>");
out.print("alert('请检查用户名和密码!');");
//out.print("backward()");
out.print("</script>");
response.sendRedirect("login.jsp");
}
%>
在tomcat显示aq.executeQuery:null