注册验证java代码[针对上篇文章]

%@ page contentType="text/html; charset=gb2312" language="java"%>
%@ page import="java.sql.*"%>
!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
html>
head>
meta http-equiv="Content-Type" content="text/html; charset=gb2312">
title>用户注册/title>
/head>
body>
%
String strSql="";
String database_username="root";
String database_password="";
String url="jdbc:mysql://localhost/ch3?useUnicode=truecharacterEncoding=gb2312";
try
{
Class.forName("org.gjt.mm.mysql.Driver");
Connection dbConn= DriverManager.getConnection(url,database_username,database_password);
Statement stmt=dbConn.createStatement();
ResultSet rs=null;
String s_UserName = request.getParameter("UserName");
strSql = "select * from users where UserName like '"+s_UserName+"'";
rs = stmt.executeQuery(strSql);
if(rs.next())
{
out.println("h1 align=center>用户名font color=red>"+s_UserName+"/font>已经存在！/h1>");
out.println("div align=center>input type=button name=btn value=返回 onClick='window.history.go(-1)'>/div>");
}
else
{
String s_UserPassword = request.getParameter("UserPassword");
String s_NickName = request.getParameter("NickName");
String s_Sex = request.getParameter("Sex");
String s_Email = request.getParameter("Email");
strSql = "insert into users (UserName,UserPassword,NickName,Sex,Email) values('"+s_UserName+"','"+s_UserPassword+"','"+s_NickName+"','"+s_Sex+"','"+s_Email+"')";
try
{
stmt.executeUpdate(strSql);
out.println("h1 align=center>用户注册成功，您的注册信息如下/h1>");
out.println("p align=center>用户名：font color=blue>"+s_UserName+"/font>/p>");
out.println("p align=center>密码：font color=blue>"+s_UserPassword+"/font>/p>");
out.println("p align=center>昵称：font color=blue>"+s_NickName+"/font>/p>");
if(s_Sex.equals("0"))
{
out.println("p align=center>性别：font color=blue>男/font>/p>");
}
else
{
out.println("p align=center>性别：font color=blue>女/font>/p>");
}
out.println("p align=center>Email：font color=blue>"+s_Email+"/font>/p>");
}
catch(Exception ex)
{
out.println("h1 align=center>用户注册失败/h1>");
out.println("div align=center>input type=button name=btn1 value=返回 onClick='window.history.go(-1)'>/div>");
}
}
rs.close();
stmt.close();
dbConn.close();
}
catch(Exception ex)
{
out.println("h1 align=center>数据库连接错误/h1>");
out.println("div align=center>input type=button name=btn2 value=返回 onClick='window.history.go(-1)'>/div>");
}
%>
/body>
/html>