Unable to compile class for JSP - Java / Web 开发

<%@page language="java" contentType="text/html;charset=gb2312" import="java.sql.*"%>
<jsp:useBean id="db" class="wang.connectDB"/>
<% 
  String name=request.getParameter("username");
  String psw=request.getParameter("password");
  if(name==null||psw==null||name.equals("")||psw.equals(""))
  {
  session.setAttribute("error","1");
  response.sendRedirect("error.jsp");
  }
  else
  {
  try
  {
  String sql="select * from userlogin where user_name='"+name+"' and user_psw='"+psw+"'";
  ResultSet rs=db.executeQuery(sql); 
  if(rs.next())
  {
  String priority=rs.getString("user_priority");
  Session.setAttribute("username",name);
  Session.setAttribute("userpsw",psw);
  Session.setAttribute("userid",rs.getString("user_id"));
  Session.setAttribute("userpriority",priority);
  response.sendRedirect("list.jsp");
  }
  else
  {
  Session.setAttribute("error&q