web连接数据库完成登录注册

秒速五厘米 2023-10-08 17:53 9阅读 0赞

## 完整文件目录如下： ##

![549dd304ba6340eba6c5aacf501851b3.png][]

1.  ## 主页面的编写（.jsp文件） ##

<html>
      <head>
        <title>淘宝网</title>
      </head>
      <body>
      <h1>欢迎来到主页面！</h1>
      <a href="Login.jsp">去登陆</a><br>
      <a href="register.jsp">去注册</a>
      </body>
    </html>

给客户两个选项（登陆/注册）---完成页面如下

![a2aad7e971d4f3387faa967c982da503.png][]

**1.登陆页面编写**

<html>
    <head>
        <title>登陆页面</title>
    </head>
    <body>
        <h2>欢迎学习WEB！</h2>
        <form action="login" method="post">
            账号：<input type="text" name="username" value=""> <br>
            密码：<input type="password" name="password" value=""> <br>
            <input type="submit" value="登录">
        </form>
    </body>
    </html>

### 1.2注册页面 ###

<html>
    <head>
        <title>注册页面</title>
    </head>
    <body>
        <h1>注册页面</h1>
        <form action="register" method="post">
            账号：<input type="text" name="username" value=""> <br>
            密码：<input type="password" name="password" value=""> <br>
            再次输入密码：<input type="password" name="password" value=""> <br>
            手机号：<input type="text" name="phone" value=""> <br>
            地址：<input type="text" name="address" value=""> <br>
            <input type="submit" value="注册">   
            <a href="Login.jsp">已有账号？点击登录</a>
        </form>
    </body>
    </html>

### 1.3项目页面 ###

<html>
    <head>
        <title>主页</title>
    </head>
    <body>
        <h1>欢迎项目主页</h1>
        <h2>主页信息展示</h2>
        <table>
            <thead>
            <tr>
                <th>商品编号</th>
                <th>商品名称</th>
                <th>商品价格</th>
                <th>商品介绍</th>
            </tr>
            </thead>
     
            <tbody id="list">
                <%
                    // 获取session
                    HttpSession session1 = request.getSession();
                    // 从session中取出数据
                    List<Goods> goodsList = (List<Goods>) session1.getAttribute("goodsList");
                    // 遍历集合中的元素
                    for (Goods goods : goodsList) {
                %>
                    
                    <tr>
                        <td><%=goods.getGid()%></td>
                        <td><%=goods.getGname()%></td>
                        <td><%=goods.getPrice()%></td>
                        <td><%=goods.getMark()%></td>
                    </tr>
                <%
                    }
                %>
     
            </tbody>
        </table>
     
    </body>
    </html>

**1.4错误页面**

<html>
    <head>
        <title>错误页</title>
    </head>
    <body>
        <h1>密码输入错误！！！</h1>
        <a href="index.jsp">回到主页</a> <br>
        <a href="Login.jsp">回到登录页</a>
    </body>
    </html>

###  **2.登陆页面编写** ###

<html>
    <head>
        <title>登陆页面</title>
    </head>
    <body>
        <h1>登陆页面</h1>
        <h2>欢迎学习WEB！</h2>
        <form action="login" method="post">
            账号：<input type="text" name="username" value=""> <br>
            密码：<input type="password" name="password" value=""> <br>
            <input type="submit" value="登录">   
            <a href="register.jsp">没有账号？点击注册</a>
        </form>
    </body>
    </html>

### 2.1实体类 ###

package com.man.dao;
     
    public class User {
        private Integer uid;
        private String username;
        private String password;
        private String phone;
        private String address;
     
        public User() {
        }
     
        public User(Integer uid, String username, String password, String phone, String address) {
            this.uid = uid;
            this.username = username;
            this.password = password;
            this.phone = phone;
            this.address = address;
        }
     
        public Integer getUid() {
            return uid;
        }
     
        public void setUid(Integer uid) {
            this.uid = uid;
        }
     
        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;
        }
     
        public String getPhone() {
            return phone;
        }
     
        public void setPhone(String phone) {
            this.phone = phone;
        }
     
        public String getAddress() {
            return address;
        }
     
        public void setAddress(String address) {
            this.address = address;
        }
     
        @Override
        public String toString() {
            return "User{" +
                    "uid=" + uid +
                    ", username='" + username + '\'' +
                    ", password='" + password + '\'' +
                    ", phone='" + phone + '\'' +
                    ", address='" + address + '\'' +
                    '}';
        }
    }

goods类

package com.man.bean;
     
    public class Goods {
     
        private Integer gid;
        private String gname;
        private Double price;
        private String mark;
     
     
        public Integer getGid() {
            return gid;
        }
     
        public void setGid(Integer gid) {
            this.gid = gid;
        }
     
        public String getGname() {
            return gname;
        }
     
        public void setGname(String gname) {
            this.gname = gname;
        }
     
        public Double getPrice() {
            return price;
        }
     
        public void setPrice(Double price) {
            this.price = price;
        }
     
        public String getMark() {
            return mark;
        }
     
        public void setMark(String mark) {
            this.mark = mark;
        }
     
        @Override
        public String toString() {
            return "Goods{" +
                    "gid=" + gid +
                    ", gname='" + gname + '\'' +
                    ", price=" + price +
                    ", mark='" + mark + '\'' +
                    '}';
        }
    }

### 2.2编写登录java代码 ###

![03a3f6464274492d81990f503b723305.png][]

package com.man.servlet;
     
     
    import com.man.services.User;
     
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
     
    public class Login extends HttpServlet {
        @Override
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            System.out.println("Login-doGet...");
            doPost(request,response);
        }
     
        @Override
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            System.out.println("Login-doPost...");
            // 1.设置请求和响应的编码格式，以及响应的格式
            request.setCharacterEncoding("utf-8"); // 设置获取数据的格式
            response.setCharacterEncoding("utf-8");
            response.setContentType("text/html:charset=UTF-8");//以什么样的格式（文本/网页）响应
     
            // 2.获取请求的参数
            String username = request.getParameter("username"); //根据表单的name属性获取用户输入的账号密码
            String password = request.getParameter("password");
            System.out.println(username);
            System.out.println(password);
     
            // 3.执行业务处理
            Connection connection = null;
            PreparedStatement pstm = null;
            ResultSet rs = null;
            User login = null;
     
     
            try{
                // 1.加载数据库驱动
                Class.forName("com.mysql.jdbc.Driver");
                // 2.获取数据库连接
                connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydb?useSSL=false&serverTimezone=UTC","root","root");
                // 3.定义登陆的sql语句
                String sql = "select * from t_user where username=? and password=?" ;
                // 4.获取预处理对象
                pstm = connection.prepareStatement(sql);
                // 5.传参
                pstm.setObject(1,username);
                pstm.setObject(2,password);
                // 6.执行查询
                rs = pstm.executeQuery();
                // 7.解析结果集
                if (rs.next()){
                    login = new User();
                    // 从结果集中获取数据，封装到实体类中
                    login.setUid(rs.getInt("uid"));
                    login.setUsername(rs.getString("username"));
                    login.setPassword(rs.getString("password"));
                    login.setPhone(rs.getString("phone"));
                    login.setAddress(rs.getString("address"));
                }
            } catch (Exception e){
                e.printStackTrace();
            } finally {
                // 8.关闭资源
                try{
                    if (rs!=null){
                        rs.close();
                    }
                    if (pstm!=null){
                        pstm.close();
                    }
                    if (connection!=null){
                        connection.close();
                    }
     
                }catch (Exception e){
                    e.printStackTrace();
                }
     
            }
     
     
            // 4.判断登陆信息是否为空
            if (login!=null){
                // 登陆成功,跳转到主页
                response.sendRedirect("zhuye.jsp");
            }else {
                // 登陆失败，跳转到错误页
                response.sendRedirect("error.jsp");
            }
        }
    }

userDao类

package com.man.dao;
     
    import com.man.bean.User;
    import com.man.util.JDBCUtil;
     
    import java.sql.Connection;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
     
    public class UserDao {
     
        Connection con = null;
        ResultSet rs = null;
        PreparedStatement pstm = null;
        User login = null;
        int row = 0;
     
        public User login(String username, String password) {
            try{
                // 1.获取数据库连接
                con = JDBCUtil.getCon();
                // 2.定义登陆的sql语句
                String sql = "select * from t_user where username=? and password=?" ;
                // 3.获取预处理对象
                pstm = con.prepareStatement(sql);
                // 4.传参
                pstm.setObject(1,username);
                pstm.setObject(2,password);
                // 5.执行查询
                rs = pstm.executeQuery();
                // 6.解析结果集
                if (rs.next()){
                    login = new User();
                    // 从结果集中获取数据，封装到实体类中
                    login.setUid(rs.getInt("uid"));
                    login.setUsername(rs.getString("username"));
                    login.setPassword(rs.getString("password"));
                    login.setPhone(rs.getString("phone"));
                    login.setAddress(rs.getString("address"));
                }
            } catch (Exception e){
                e.printStackTrace();
            }
            return login;
        }
     
        public int register(User user) {
            try{
                // 1.获取数据库连接
                con = JDBCUtil.getCon();
                // 2.定义注册的新增sql语句
                String sql = "insert into t_user(username,password,phone,address) values(?,?,?,?)" ;
                // 3.获取预处理对象
                pstm = con.prepareStatement(sql);
                // 4.传参
                pstm.setObject(1,user.getUsername());
                pstm.setObject(2,user.getPassword());
                pstm.setObject(3,user.getPhone());
                pstm.setObject(4,user.getAddress());
                // 5.执行更新（增删改）
                row = pstm.executeUpdate();
            }catch (Exception e){
                e.printStackTrace();
            } finally {
                JDBCUtil.close(con,pstm);
            }
     
            return row;
        }
    }

![fc83f95f70e2436ba2a1322c544389de.png][]

login类代码

package com.man.servlet;
     
     
    import com.man.bean.User;
    import com.man.dao.UserDao;
    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 java.io.IOException;
     
    @WebServlet("/login")
    public class Login extends HttpServlet {
        @Override
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            System.out.println("Login-doGet...");
            doPost(request,response);
        }
     
        @Override
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            // 1.设置请求和响应的编码格式，以及响应的格式
            request.setCharacterEncoding("utf-8"); // 设置获取数据的格式
            response.setCharacterEncoding("utf-8");
            response.setContentType("text/html:charset=UTF-8");//以什么样的格式（文本/网页）响应
     
            // 2.获取请求的参数
            String username = request.getParameter("username"); //根据表单的name属性获取用户输入的账号密码
            String password = request.getParameter("password");
            System.out.println(username);
            System.out.println(password);
     
            // 3.执行业务处理
            UserDao userDao = new UserDao();
            User login = userDao.login(username, password);
     
            // 4.判断登陆信息是否为空
            if (login!=null){
                // 登陆成功,当前servlet业务处理完毕---后续操作由别人完成---请求别的地址
                request.getRequestDispatcher("selectAllGoods").forward(request,response);
            }else {
                // 登陆失败，跳转到错误页
                response.sendRedirect("error.jsp");
            }
        }
    }

SelectAllGoods 类

package com.man.servlet;
     
    import com.man.bean.Goods;
    import com.man.dao.GoodsDao;
     
    import javax.servlet.*;
    import javax.servlet.http.*;
    import javax.servlet.annotation.*;
    import java.io.IOException;
    import java.util.List;
     
    @WebServlet("/selectAllGoods")
    public class SelectAllGoods extends HttpServlet {
        @Override
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            System.out.println("SelectAllGoods-doGet...");
            doPost(request,response);
        }
     
        @Override
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            // 1.执行查询业务
            // 2.查询所有商品信息
            GoodsDao goodsDao = new GoodsDao();
            List<Goods> goodsList = goodsDao.selectAllGoods();
            System.out.println(goodsList);
            // 3.把数据传递到前端页面
            // 3.1通过request获取session对象，该对象可以向前端传输数据的容器
            HttpSession session = request.getSession();
            // 4.向session中存入商品信息集合
            session.setAttribute("goodsList",goodsList);
     
            // 4.登录成功,跳转到登录页
            response.sendRedirect("zhuye.jsp");
     
        }
    }

### 2.3工具类文件 ###

package com.man.util;
     
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
     
    public class JDBCUtil {
     
        private static String driver = "com.mysql.jdbc.Driver";
        private static String url = "jdbc:mysql://localhost:3306/mydb?useSSL=false&serverTimezone=UTC";
        private static String user = "root";
        private static String psw = "root";
     
        int row = 0;
        static Connection con = null;
     
        public static Connection getCon(){
     
            try{
                // 1.加载数据库驱动
                Class.forName(driver);
                // 2.获取数据库连接
                con = DriverManager.getConnection(url, user, psw);
     
            } catch (Exception e){
                e.printStackTrace();
            }
            return con;
        }
     
        public static void close(ResultSet rs,Connection con,PreparedStatement pstm){
            // 关闭资源
            try{
                if (rs!=null){
                    rs.close();
                }
                if (pstm!=null){
                    pstm.close();
                }
                if (con!=null){
                    con.close();
                }
     
            }catch (Exception e){
                e.printStackTrace();
            }
        }
        public static void close(Connection con,PreparedStatement pstm){
            // 关闭资源
            try{
                if (pstm!=null){
                    pstm.close();
                }
                if (con!=null){
                    con.close();
                }
     
            }catch (Exception e){
                e.printStackTrace();
            }
        }
    }

输入正确信息，数据库比对过后进入主页面

![92f74387d4444bf8a38a67c7bd3727f7.png][]

反之则进入错误页 ![8c0abdf53b82483ebc32e7001f5b10ba.png][]

**3.注册页面**

<html>
    <head>
        <title>注册页面</title>
    </head>
    <body>
        <h2>欢迎学习WEB！</h2>
        <form action="zhuce" method="post">
            账号：<input type="text" name="username" value=""> <br>
            密码：<input type="password" name="password" value=""> <br>
            再次输入密码：<input type="password" name="password" value=""> <br>
            手机号：<input type="text" name="phone" value=""> <br>
            地址：<input type="text" name="address" value=""> <br>
            <input type="submit" value="注册">
        </form>
    </body>
    </html>

### 3.1编写注册java代码 ###

package com.man.servlet;
     
    import com.man.dao.User;
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.PreparedStatement;
     
    public class Zhuce extends HttpServlet {
        @Override
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            System.out.println("Zhuce-doGet...");
            doPost(request, response);
        }
     
        @Override
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            System.out.println("Zhuce-doPost...");
            // 1.设置请求和响应的编码格式，以及响应的格式
            request.setCharacterEncoding("utf-8"); // 设置获取数据的格式
            response.setCharacterEncoding("utf-8");
            response.setContentType("text/html:charset=UTF-8");//以什么样的格式（文本/网页）响应
     
            // 2.获取请求的参数
            String username = request.getParameter("username"); //根据表单的name属性获取用户输入的账号密码
            String password = request.getParameter("password");
            String phone = request.getParameter("phone");
            String address = request.getParameter("address");
            System.out.println(username);
            System.out.println(password);
            System.out.println(phone);
            System.out.println(address);
     
            // 3.执行业务处理
            Connection connection = null;
            PreparedStatement pstm = null;
            User zhuce = null;
            int a = 0;
     
            try{
                // 1.加载数据库驱动
                Class.forName("com.mysql.cj.jdbc.Driver");
                // 2.获取数据库连接
                connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydb?useSSL=false&serverTimezone=UTC","root","root");
                // 3.定义登陆的sql语句
                String sql = "insert into t_user(username,password,phone,address) values(?,?,?,?)" ;
                // 4.获取预处理对象
                pstm = connection.prepareStatement(sql);
                // 5.传参
                pstm.setObject(1,username);
                pstm.setObject(2,password);
                pstm.setObject(3,phone);
                pstm.setObject(4,address);
                a = pstm.executeUpdate();
                zhuce = new User();
                zhuce.setUsername(username);
                zhuce.setPassword(password);
                zhuce.setPhone(phone);
                zhuce.setAddress(address);
                // 6.处理结果
                if (a > 0) {
                    System.out.println("新增成功");
                } else {
                    System.out.println("新增失败");
                }
            } catch (Exception e){
                e.printStackTrace();
            } finally {
                // 8.关闭资源
                try{
                    if (pstm!=null){
                        pstm.close();
                    }
                    if (connection!=null){
                        connection.close();
                    }
     
                }catch (Exception e){
                    e.printStackTrace();
                }
     
            }
     
     
            // 4.判断登陆信息是否为空
            if (a > 0){
                // 登陆成功,跳转到主页
                response.sendRedirect("zhuye.jsp");
            }else {
                // 登陆失败，跳转到错误页
                response.sendRedirect("error.jsp");
            }
        }
    }

// 执行业务处理部分用到的代码与登录业务代码在同一 .java 文件中

@Override
        public int register(User user) {
            try{
                // 1.获取数据库连接
                con = JDBCUtil.getCon();
                // 2.定义注册的新增sql语句
                String sql = "insert into t_user(username,password,phone,address) values(?,?,?,?)" ;
                // 3.获取预处理对象
                pstm = con.prepareStatement(sql);
                // 4.传参
                pstm.setObject(1,user.getUsername());
                pstm.setObject(2,user.getPassword());
                pstm.setObject(3,user.getPhone());
                pstm.setObject(4,user.getAddress());
                // 5.执行更新（增删改）
                row = pstm.executeUpdate();
            }catch (Exception e){
                e.printStackTrace();
            } finally {
                JDBCUtil.close(con,pstm);
            }
     
            return row;
        }

![6097d8752ea54e8aa2e4dcddfdb89a29.png][]

输入信息点击 注册，自动跳转登录页

![c0d5e1cbd7494c5089e84d095e53deca.png][]

将刚刚注册的账号密码输入，登录进入项目主页

![b6697d808aca4f639aef1bb9da09d446.png][]

### 4.完成servlet映射关系配置 ###

#### 4.1映射方法一 ####

<?xml version="1.0" encoding="UTF-8"?>
    <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
             version="4.0">
        
        <servlet>
            
            <servlet-name>login</servlet-name>
            <servlet-class>com.man.servlet.Login</servlet-class>
            
        </servlet>
        
        <servlet-mapping>
            <servlet-name>login</servlet-name>
            <url-pattern>/login</url-pattern>
        </servlet-mapping>
        
        <servlet>
            <servlet-name>zhuce</servlet-name>
            <servlet-class>com.man.servlet.Zhuce</servlet-class>
        </servlet>
        
        <servlet-mapping>
            <servlet-name>zhuce</servlet-name>
            <url-pattern>/zhuce</url-pattern>
        </servlet-mapping>
     
    </web-app>

#### 4.2映射方法二 ####

将@[WebServlet][]("/想跳转的页面")写在代码最外层，即可完成映射

![799b3faf24c69e353ae928fee1803b55.png][]

![08df5111a57db9d186f0621d2f33a18e.png][]

## 5.MYSQL代码部分 ##

#判断存在即删除数据库
    drop database if exists mydb;
    #创建数据库
    create database mydb;
    #使用数据库
    use mydb;
     
     
    #创建表
    create table t_user
    (
        uid int primary key auto_increment,
        username varchar(20),
        password varchar(20),
        phone varchar(11),
        address varchar(50)
    );
     
     
    insert into t_user(username,password,phone,address) values('张三','666','18965423548','南阳');
    insert into t_user(username,password,phone,address) values('李四','333','18754263548','许昌');
    insert into t_user(username,password,phone,address) values('小美','123','18565234759','信阳');
     
    select * from t_user where username=? and password=?
    select * from t_user;
     
     
    create table t_goods
    (
        gid int primary key auto_increment,
        gname varchar(20),
        price double,
        mark varchar(100)
    );
     
    insert into t_goods(gname,price,mark) values('泡面',4.5,'够香够辣就是这个味！');
    insert into t_goods(gname,price,mark) values('火腿',8.5,'肉质细腻Q弹！');
    insert into t_goods(gname,price,mark) values('雪碧',3.5,'清爽冰凉随心爽！');
     
    select * from t_goods;

![41d7828b7462469a8fe7f3c24477b03e.png][]

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[WebServlet]: https://so.csdn.net/so/search?q=WebServlet&spm=1001.2101.3001.7020
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