package com.bjsxt.registration.model;

//贫血模型 充血模型
public class User {
  private Integer id;
  private String username;
  private String password;

  public Integer getId() {
    return id;
  }

  public void setId(Integer id) {
    this.id = id;
  }

  public String getUsername() {
    return username;
  }

  public void setUsername(String username) {
    this.username = username;
  }

  public String getpassword() {
    return password;
  }

  public void setpassword(String password) {
    this.password = password;
  }

}


package com.bjsxt.registration.service;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

import com.bjsxt.registration.model.User;

public class UserManager {
  public boolean exists(User u) throws Exception {
    Class.forName("com.mysql.jdbc.Driver");
    Connection conn = DriverManager.getConnection(
        "jdbc:mysql://localhost:3306/spring", "root", "root");

    String sqlQuery = "select count(*) from user where username = ?";
    PreparedStatement psQuery = conn.prepareStatement(sqlQuery);
    psQuery.setString(1, u.getUsername());
    ResultSet rs = psQuery.executeQuery();
    rs.next();
    int count = rs.getInt(1);
    psQuery.close();
    conn.close();
    if (count > 0) {
      return true;
    }
    return false;
  }

  public void add(User u) throws Exception {
    Class.forName("com.mysql.jdbc.Driver");
    Connection conn = DriverManager.getConnection(
        "jdbc:mysql://localhost:3306/spring", "root", "root");

    String sql = "insert into user values (null, ?, ?)";
    PreparedStatement ps = conn.prepareStatement(sql);
    ps.setString(1, u.getUsername());
    ps.setString(2, u.getpassword());
    ps.executeUpdate();
    ps.close();
    conn.close();
  }
}


<%@ page language="java" import="java.util.*" pageEncoding="GB18030"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>

<title>用户注册</title>

<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">

</head>

<body>
  <h1>用户注册</h1><br/>
  <form action="registDeal.jsp" method="post">
    用户名：<input type="text" name="username"/><br/>
    密码：<input type="password" name="password"/><br/>
    确认密码：<input type="password" name="password2"/><br/>
    <input type="submit" value=" 提 交 "/>
  </form>
</body>
</html>
<%@ page language="java" import="java.util.*, java.sql.*"
  pageEncoding="GB18030"%>
<%@ page import="com.bjsxt.registration.model.User"%>
<%@ page import="com.bjsxt.registration.service.UserManager"%>
<%
  String path = request.getContextPath();
  String basePath = request.getScheme() + "://"
      + request.getServerName() + ":" + request.getServerPort()
      + path + "/";
  String username = request.getParameter("username");
  String password = request.getParameter("password");
  String password2 = request.getParameter("password2");

  User u = new User();
  u.setUsername(username);
  u.setpassword(password);

  UserManager um = new UserManager();
  boolean exits = um.exists(u);
  if (exits) {
    response.sendRedirect("registFail.jsp");
    return;
  }

  um.add(u);
  response.sendRedirect("registSuccess.jsp");
%>


<%@ page language="java" import="java.util.*" pageEncoding="GB18030"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>

<title>失败</title>

<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">

</head>

<body>
  <h1>Fail!</h1>
</body>
</html>


<%@ page language="java" import="java.util.*" pageEncoding="GB18030"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>

<title>成功</title>

<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">

</head>

<body>
  <h1>Success!</h1>
</body>
</html>