基于jsp+servlet完成的用户注册

 思考 ： 需要创建实体类吗? 需要创建表吗

　　　　|----User  存在、不需要创建了！表同理、也不需要了

1.设计dao接口

package cn.javabs.usermanager.dao;

import cn.javabs.usermanager.entity.User;

/**
 * 用户的dao接口的设计
 * @author Mryang
 *
 */
public interface UserDao {
	
	/**
	 * 用户登录功能
	 * @param username 参数  为用户名
	 * @param password 参数 为密码
	 * @return  user
	 */
	User login(String username , String password);
	
	/**
	 * 用户注册
	 * @param user 参数是  用户对象！！！！！！！
	 * @return  记录条数  受影响的行数
	 */
	int register(User user);
	
}

　2.UserDaoImpl 实现类

package cn.javabs.usermanager.dao.impl;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import cn.javabs.usermanager.dao.UserDao;
import cn.javabs.usermanager.entity.User;
import cn.javabs.usermanager.exception.UserLoginException;
import cn.javabs.usermanager.exception.UserRegisterException;
import cn.javabs.usermanager.util.JdbcUtil;
/**
 * userdao的实现类
 * @author Mryang
 *	调用 jdbc
 *
 *静态方法优于构造方法先执行
 *
 */
public class UserDaoImpl implements UserDao {

	
	@Override
	public User login(String username, String password) {
		
		
		try {
			
			Connection con = JdbcUtil.getConnection();
			
			// 通过con 链接创建一个执行SQL语句的对象Statement
			Statement st = con.createStatement();
			
			ResultSet rs = st.executeQuery("select * from  user  where username = '"+username+"'  and password = '"+password+"';");
			
			if(rs.next()){// 有数据才执行以下
			// 类型   对象  = 。。。
				User user =  new User();
				
//				rs.getString();//columnIndex  数据库中表的列号  从0计数
//				rs.getString(columnLabel)//columnLabel 数据库中表的列名
				
//				String name = rs.getString("username");//name  admin
//				String pwd = rs.getString("password");//name  admin
//				System.out.println("name:"+name);
//				System.out.println("pwd:"+pwd);
//				user.setUsername(name);
				// 封装。注入
				user.setUsername(rs.getString("username"));
				
				user.setPassword(rs.getString("password"));
				
				System.out.println("userDao中的user的内容是"+ user);
				
				return user;// 已经有了 username和password
				
				
			}else{//没数据才执行以下
				return null;
			}
			
			
		} catch (SQLException e) {
			throw  new UserLoginException();
		}
		
		
		
	}

	@Override
	public int register(User user) {
		
		try {
			// 获取链接
			Connection conn = JdbcUtil.getConnection();
			
			// 创建执行SQL语句的对象
			Statement st = conn.createStatement();
			
			int row = st.executeUpdate("insert into user(username,password,sex) values ('"+user.getUsername()+"','"+user.getPassword()+"','"+user.getSex()+"')");
			
			return row;
					
		} catch (SQLException e) {
			throw  new UserRegisterException();
		}
	}
			
			
			

}

　　3.service接口设计

package cn.javabs.usermanager.service;

import cn.javabs.usermanager.entity.User;

public interface UserService {


	/**
	 * 用户登录功能
	 * @param username 参数  为用户名
	 * @param password 参数 为密码
	 * @return  user
	 */
	User userLogin(String username , String password);
	
	/**
	 * 用户注册
	 * @param user
	 * @return
	 */
	int userRegist(User user);
	
}

　　

serviceImpl

package cn.javabs.usermanager.service.impl;

import cn.javabs.usermanager.dao.UserDao;
import cn.javabs.usermanager.dao.impl.UserDaoImpl;
import cn.javabs.usermanager.entity.User;
import cn.javabs.usermanager.service.UserService;

public class UserServiceImpl implements UserService {
	
	// 采用多态的形式进行实例化dao  
	UserDao dao = new  UserDaoImpl();
	
	@Override
	public User userLogin(String username, String password) {
		//dao代表的是UserDao 这个接口
//		.login  用这个接口中的用户登录功能  并且传了两个参数给你
		return dao.login(username, password);
	}

	@Override
	public int userRegist(User user) {
		
		return dao.register(user);
	}

}

UserServlet

package cn.javabs.usermanager.web.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import cn.javabs.usermanager.entity.User;
import cn.javabs.usermanager.service.UserService;
import cn.javabs.usermanager.service.impl.UserServiceImpl;

public class UserLoginServlet extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		/*
		 * 1 set encoding
		 */
		response.setContentType("text/html");
		response.setCharacterEncoding("utf-8");
		request.setCharacterEncoding("utf-8");
		
		/*
		 * 2. get 前台  的  参数
		 */
		String username = request.getParameter("username");
		String password = request.getParameter("password");
	
		/*
		 * 3. 将获取到的用户名和密码传递给 userService!
		 * 所以 得有  userService  没有  怎么  办?  实例化  就有了 
		 */
		UserService userService = new UserServiceImpl();
		
		User u = userService.userLogin(username, password);//u可能为前面传递过来的user或是null
		
		if(u == null){
			response.getWriter().write("您的用户名或密码有误，请检查！");
			response.setHeader("Refresh", "5;Url="+ request.getContextPath());
		}else{
			request.setAttribute("mark", "用户登录成功！");
			request.getRequestDispatcher("/message.jsp").forward(request, response);
		}
	
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doGet( request,  response);
	}

}　　

　register.jsp

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>注册</title>
  </head>
  
  <body>
   		<center>
	   			<form action="<%=basePath%>servlet/UserRegistServlet" method="post" >
				<table border="1px" width="438px"   >
					<tr align="center">
						<td colspan="2">
							<a href="<%=basePath%>login.jsp">如已有用户，点击去登录</a>
						</td>
					</tr>
					<tr align="center">
						<td>用户名</td>
						<td>
							<input type="text" name="username" >
						</td>
					</tr>
					<tr align="center">
						<td>密码</td>
						<td>
							<input type="password" name="password" >
						</td>
					</tr>
					<tr align="center">
						<td>性别</td>
						<td>
							男<input type="radio" name="sex" value="男" checked="checked" >
							女<input type="radio" name="sex" value="女" >
						</td>
					</tr>
					<tr align="center">
						<td colspan="2" >
							<input type="submit" value="免费注册" >
							  
							<input type="reset" value="重置内容" >
						</td>
					</tr>
				</table>   			
	   		</form>
   		</center>
  </body>
</html>