<%@ page language="java" contentType="text/html; charset=GB18030"    pageEncoding="GB18030"%>
 <%@ page import="java.sql.*" errorPage="" %>
 <jsp:useBean id="connBean" scope="page" class="JavaBean.connDB"/>
 <% 
 request.setCharacterEncoding("GB2312");
 String userName = request.getParameter("username");
 String password = request.getParameter("password");
 
 if(userName == ""){%>
 <script language="javascript">
 alert("your username is empty");
 history.back();
 </script>
 <%} %>
<%
  ResultSet rs = connBean.executeQuery("SELECT * FROM LoginInformation WHERE UserName='"+userName+"'");
  if(rs.next()){ 
     String rsPassword=rs.getString("Password");
	 if(password.equals(rsPassword)){
  %>
  <script language="javascript">
   window.location.href="HomePage.jsp";
  </script>
<%}else{

%>
  <script language="javascript">
  alert("your password is wrong!please input it again!");
  history.back();
  </script>
<%}}
  else{ %>
 <script language="javascript">
  alert("your userName is wrong!please input it again!");
 history.back();
  </script>
<%} %>