JavaWeb 实现简单登录、注册功能

1.首先创建一个简单的动态Javaweb项目

2.然后手动建立文件目录：

项目创建好之后，在src下建几个包：

controller：控制器，负责转发请求，对请求进行处理，主要存放servlet；

dao：数据库管理，主要是写数据库操作方法；

model：存放实体类；

service：业务逻辑的处理；

util：存放工具类，在这里我主要是把数据库加载驱动和创立连接、关闭连接封装成了一个静态类。

ps:别忘了在lib文件夹里放入这个jar包，用以连接数据库。

3.下面直接贴上对应的代码：

 src代码：

package com.maike.controller;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.maike.service.UserService;
import com.maike.service.UserServiceImpl;

/**
 * Servlet implementation class RegisterServlet
 */
@WebServlet("/RegisterServlet")
public class RegisterServlet extends HttpServlet {
    UserService userService = new UserServiceImpl();
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public RegisterServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        response.getWriter().append("Served at: ").append(request.getContextPath());
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        request.setCharacterEncoding("utf-8");
        String userName = request.getParameter("userName");
        String userPwd = request.getParameter("userPwd");
        String userRePwd = request.getParameter("userRePwd");
        
        int k = userService.insertUser(userName,userPwd,userRePwd);
        
        if(k > 0) {
            request.getRequestDispatcher("login.jsp").forward(request, response);
        }else {
            request.getRequestDispatcher("register.jsp").forward(request, response);
        }
    }

}

package com.maike.controller;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.maike.service.UserService;
import com.maike.service.UserServiceImpl;

/**
 * Servlet implementation class LoginServlet
 */
@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
    UserService userService = new UserServiceImpl();
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public LoginServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        response.getWriter().append("Served at: ").append(request.getContextPath());
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        request.setCharacterEncoding("utf-8");
        String userName = request.getParameter("userName");
        String uesrPwd = request.getParameter("userPwd");
        
        int k = userService.judgeLogin(userName,uesrPwd);
        if(k > 0) {
            request.getRequestDispatcher("success.jsp").forward(request, response);
        }else {
            request.getRequestDispatcher("login.jsp").forward(request, response);
        }
    }

}

package com.maike.dao;

import com.maike.model.User;

public interface UserDao {
    
    int insert(String userName,String userPwd);
    User selectByName(String userName);

}

package com.maike.dao;

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

import com.maike.model.User;
import com.maike.util.ConnectionUtil;

public class UserDaoImpl implements UserDao {
    Connection con = null;
    PreparedStatement pt = null;
    ResultSet rs = null;
    String sql;

    @Override
    public int insert(String userName, String userPwd) {
        // TODO Auto-generated method stub
        int k = 0;
        sql = "insert into user value(null,?,?)";
        try {
            con = ConnectionUtil.getConnection();
            pt = con.prepareStatement(sql);
            pt.setString(1, userName);
            pt.setString(2, userPwd);
            k = pt.executeUpdate();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally {
            ConnectionUtil.closeRe(con, pt);
        }
        return k;
    }

    @Override
    public User selectByName(String userName) {
        // TODO Auto-generated method stub
        sql = "select * from user where user_name = ?";
        User user = new User();
        try {
            con = ConnectionUtil.getConnection();
            pt = con.prepareStatement(sql);
            pt.setString(1, userName);
            rs = pt.executeQuery();
            
            while(rs.next()) {
                user.setUserId(rs.getInt("user_id"));
                user.setUserName(rs.getString("user_name"));
                user.setUserPwd(rs.getString("user_pwd"));
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally {
            ConnectionUtil.closeRe(con, pt, rs);
        }
        return user;
    }

}

package com.maike.model;

public class User {
    
    private int userId;
    
    private String userName;
    
    private String userPwd;

    public int getUserId() {
        return userId;
    }

    public void setUserId(int userId) {
        this.userId = userId;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getUserPwd() {
        return userPwd;
    }

    public void setUserPwd(String userPwd) {
        this.userPwd = userPwd;
    }

    @Override
    public String toString() {
        return "User [userId=" + userId + ", userName=" + userName + ", userPwd=" + userPwd + "]";
    }

}

package com.maike.service;

public interface UserService {
    
    int insertUser(String userName,String userPwd,String userRePwd);
    int judgeLogin(String userName,String userPwd);

}

package com.maike.service;

import com.maike.dao.UserDao;
import com.maike.dao.UserDaoImpl;
import com.maike.model.User;

public class UserServiceImpl implements UserService {
    UserDao userDao = new UserDaoImpl();

    /**
     * insertUser: 实现注册功能.<br/>
     */
    @Override
    public int insertUser(String userName, String userPwd, String userRePwd) {
        // TODO Auto-generated method stub
        int k = 0;
        if(userName == "" || userName == null || userPwd == "" || userRePwd == null) {
            return k;
        }
        if(!userPwd.equals(userRePwd)) {
            return k;
        }
        
        k = userDao.insert(userName,userPwd);
        
        return k;
    }

    /**
     * judgeLogin:登录判断 .<br/>
     */
    @Override
    public int judgeLogin(String userName, String userPwd) {
        // TODO Auto-generated method stub
        int k = 0;
        if(userName == "" || userName == null || userPwd == ""|| userPwd == null) {
            return k;
        }
        User user = userDao.selectByName(userName);
        
        if(!userPwd.equals(user.getUserPwd())) {
            k = 0;
        }else {
            k = 1;
        }
        return k;
    }

}

package com.maike.util;

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

public class ConnectionUtil {
    private static String url = "jdbc:mysql://127.0.0.1/nanfeng?characterEncoding=utf8&useSSL=true";
    private static String rootName = "root";
    private static String rootPwd = "zz201608";
    
    private ConnectionUtil() {};
    
    static {
        try {
            /*加载驱动*/
            Class.forName("com.mysql.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    
    /**
     * getConnection:创建连接.<br/>
     * @return
     * @throws SQLException
     */
    public static Connection getConnection() throws SQLException {
        return DriverManager.getConnection(url,rootName,rootPwd);
    }
    
    /**
     * closeRe:关闭连接.<br/>
     * @param con
     * @param pt
     * @param rs
     */
    public static void closeRe(Connection con,PreparedStatement pt,ResultSet rs) {
        if(rs != null) {
            try {
                rs.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }finally {
                if(pt != null) {
                    try {
                        pt.close();
                    } catch (SQLException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }finally{
                        if(con != null) {
                            try {
                                con.close();
                            } catch (SQLException e) {
                                // TODO Auto-generated catch block
                                e.printStackTrace();
                            }
                        }
                    }
                }
            }
        }
    }
    
    /**
     * closeRe:关闭连接.<br/>
     * @param con
     * @param pt
     */
    public static void closeRe(Connection con,PreparedStatement pt) {
        if(pt != null) {
            try {
                pt.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }finally {
                if(con != null) {
                    try {
                        con.close();
                    } catch (SQLException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
            }
        }
    }

}

jsp页面代码：

<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<!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=utf-8">
<title>登录页面</title>
</head>
<body>
  <br><br><br>
  <h3 align = "center">登录页面</h3>
  <hr>
    <form align = "center" action="LoginServlet" method="post">
        <table align = "center" border="0">
            <tr><td>用户名</td><td><input type="text" name="userName" ></td></tr>
            <tr><td>密码</td><td><input type="password" name="userPwd" ></td></tr>
            <tr><td align = "center"><input type="submit" value = "登录" style="color:blue" ></td><td align = "right"><button><a href = "register.jsp" style="color:blue" >注册</a></button></td></tr>
        </table>
    
    </form>

</body>
</html>

<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<!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=utf-8">
<title>注册页面</title>
</head>
<body>
  <br><br><br>
  <h3 align = "center">注册页面</h3>
  <hr>
    <form align = "center" action="RegisterServlet" method="post">
        <table align = "center" border="0">
            <tr><td>用户名</td><td><input type="text" name="userName" ></td></tr>
            <tr><td>密码</td><td><input type="password" name="userPwd" ></td></tr>
            <tr><td>确认密码</td><td><input type="password" name="userRePwd" ></td></tr>
            <tr><td align = "center" colspan="2"><input type="submit" value = "注册" style="color:blue" ></td></tr>
        </table>
    
    </form>
</body>
</html>

创建数据库：

CREATE TABLE nanfeng.`user` (
    user_id INT NOT NULL AUTO_INCREMENT,
    user_name varchar(100) NULL,
    user_pwd varchar(100) NULL,
    CONSTRAINT user_pk PRIMARY KEY (user_id)
)
ENGINE=InnoDB
DEFAULT CHARSET=utf8
COLLATE=utf8_general_ci;

4.最后，启动服务器，界面效果出来了