通过Servlet来实现简易的登陆注册功能

蔚落 2023-02-22 13:39 11阅读 0赞

# 前言 #

本次课学习了如何通过web来写一个简易的登录注册功能

# 环境配置 #

1、IDEA  
2、JDK1.8（推荐用此版本）  
3、Tomcat 8.5.32  
4、Navicat for MySQL  
5、MySQL Server  
以上内容的安装及破解此处省略，那么接下来进入正题

# 实验过程 #

## 1、创建数据库 ##

打开事先安装好的Navicat for MySQL并新建数据库  
在新建的数据库下我们新建user表  
之后我们右键设计user表  
加入属性  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p2ZXJf_size_16_color_FFFFFF_t_70]  
然后在user表内添加数据  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p2ZXJf_size_16_color_FFFFFF_t_70 1]

## 2、项目文件及类的创建 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p2ZXJf_size_16_color_FFFFFF_t_70 2]  
以上是本次项目的所有文件和类，在开始说代码之前我们还需要在**lib**文件夹中添加两个依赖包  
分别是**jstl 1.2**和**mysql-connector-java-5.1.47-bin**，在下载完成后直接拖入文件夹即可  
![在这里插入图片描述][20200703235411831.png]  
拖入后我们需要右键点击Add as library来启动依赖包  
然后进行以下操作  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p2ZXJf_size_16_color_FFFFFF_t_70 3]  
![在这里插入图片描述][20200704000013573.png]  
在右侧页面中点击fix即可自动添加两个包，完成启动

## 3、JSP部分 ##

### 主页（index） ###

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <html>
      <head>
        <title>$Title$</title>
      </head>
      <body>
      <h1>登录页面</h1>
      <form action="/login" method="post">
        name:<input name="name" type="text">
        password:<input name="password" type="password">
        <input type="submit" value="login">
      </form>
      <a href="add.jsp">跳转到注册页面</a>
      <a href="search.jsp">跳转到查找页面</a>
      </body>
    </html>

### 添加页面（add） ###

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <html>
    <head>
        <title>注册</title>
    </head>
    <body>
    <h1>注册页面</h1>
    <form action="/add?method=save" method="post">
        name:<input name="name" type="text">
        password:<input name="password" type="password">
        age:<input name="age" type="text">
        <input type="submit" value="注册">
    </form>
    </body>
    </html>

### 查询页面（search） ###

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <html>
    <head>
        <title>查找</title>
    </head>
    <body>
    <form action="/add?method=search" method="post">
        <input name="name" placeholder="请输入你要查找的名字">
        <input type="submit" value="查找">
    </form>
    </body>
    </html>

## 4、类的编写 ##

### 1、数据库的连接（DBUtil） ###

getConnection内test1是自己创建的数据库的名字

package com.Jver0629.util;
    
    import java.sql.*;
    
    public class DBUtil {
        
        public static Connection getConnection() throws ClassNotFoundException, SQLException {
        
            Class.forName("com.mysql.jdbc.Driver");
            System.out.println("连接数据库");
            //创建连接
            Connection connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/test1?useSSL=false","root","123456");
            return connection;
        }
    
        public static void closeAll(ResultSet rs, Statement stmt,Connection conn)throws SQLException{
        
            if (rs != null){
        
                rs.close();
            }
            if (stmt != null){
        
                stmt.close();
            }
            if (conn != null){
        
                conn.close();
            }
    
        }
    }

### 2、配置web文件 ###

在web.xml中添加以下内容

<servlet>
            <servlet-name>addServlet</servlet-name>
            <servlet-class>com.Jver0629.servlet.AddServlet</servlet-class>
        </servlet>
    
        <servlet-mapping>
            <servlet-name>addServlet</servlet-name>
            <url-pattern>/add</url-pattern>
        </servlet-mapping>

### 3、实体类（User） ###

package com.Jver0629.model;
    
    public class User {
        
        private int id;
        private String name;
        private String password;
        private String age;
    
        //按住alt+insert
    
        public int getId() {
        
            return id;
        }
    
        public void setId(int id) {
        
            this.id = id;
        }
    
        public String getName() {
        
            return name;
        }
    
        public void setName(String name) {
        
            this.name = name;
        }
    
        public String getPassword() {
        
            return password;
        }
    
        public void setPassword(String password) {
        
            this.password = password;
        }
    
        public String getAge() {
        
            return age;
        }
    
        public void setAge(String age) {
        
            this.age = age;
        }
    
        @Override
        public String toString() {
        
            return "User{" +
                    "id=" + id +
                    ", name='" + name + '\'' +
                    ", password='" + password + '\'' +
                    ", age='" + age + '\'' +
                    '}';
        }
    }

### 4、执行方法（UserDao） ###

包含查询和添加两个方法

package com.Jver0629.dao;
    
    import com.Jver0629.model.User;
    import com.Jver0629.util.DBUtil;
    
    import javax.jws.soap.SOAPBinding;
    import java.sql.Connection;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    
    public class UserDao {
        
        public int add(User user)  {
        
            Connection connection = null;
            PreparedStatement pstmt = null;
            int count = 0;
            try {
        
                connection = DBUtil.getConnection();
                //获得执行sql的statement对象
                pstmt = connection.prepareStatement("insert into user (name,password,age) value (?,?,?)");
                pstmt.setString(1,user.getName());
                pstmt.setString(2,user.getPassword());
                pstmt.setString(3,user.getAge());
                //执行sql，获得结果
                count = pstmt.executeUpdate();
                System.out.println("insert操作："+count);
                return count;
            }catch (Exception e){
        
                e.printStackTrace();
            }finally {
        
                try {
        
                    DBUtil.closeAll(null,pstmt,connection);
                } catch (SQLException e) {
        
                    e.printStackTrace();
                }
            }
            return count;
        }
    
        public User selectByName(String name){
        
            ResultSet rs = null;
            Connection connection = null;
            PreparedStatement pstmt = null;
            DBUtil util = new DBUtil();
            User user = new User();
            try {
        
                connection = util.getConnection();
                pstmt = connection.prepareStatement("select * from user where name =?");
                pstmt.setString(1,name);
    
                rs = pstmt.executeQuery();
                //处理结果集
                while (rs.next()) {
        
                    user.setId(rs.getInt(1));
                    user.setName(rs.getString(2));
                    user.setPassword(rs.getString(3));
                    user.setAge(rs.getString(4));
                }
            } catch (Exception e) {
        
                e.printStackTrace();
            } finally {
        
                try {
        
                    util.closeAll(rs, pstmt, connection);
                } catch (SQLException e) {
        
                    e.printStackTrace();
                }
            }
            return user;
        }
    }

### 5、逻辑层（UserService） ###

package com.Jver0629.service;
    
    import com.Jver0629.dao.UserDao;
    import com.Jver0629.model.User;
    
    import java.sql.SQLException;
    
    public class UserService {
        
        UserDao userDao = new UserDao();
    
        public int add(User user)  {
        
            System.out.println("service中add方法被调用");
            return userDao.add(user);
        }
    
        public User selectByName(String name){
        
            return userDao.selectByName(name);
        }
    }

### 6、Servlet（AddServlet、HelloServlet、LoginServlet） ###

#### AddServlet ####

package com.Jver0629.servlet;
    
    
    import com.Jver0629.model.User;
    import com.Jver0629.service.UserService;
    
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    
    public class AddServlet extends HttpServlet {
        
        UserService userService = new UserService();
    
        protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        
            System.out.println("执行了doPost");
            String method = req.getParameter("method");
            if (method.equals("save")){
        
                insert(req,resp);
            }else if(method.equals("search")){
        
                search(req,resp);
            }
    
        }
        public void insert(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        
            User user = new User();
            String name = req.getParameter("name");
            String password = req.getParameter("password");
            String age = req.getParameter("age");
    
            user.setName(name);
            user.setPassword(password);
            user.setAge(age);
            System.out.println(user);
    
            int count = userService.add(user);
            if (count>0){
        
                resp.sendRedirect("/index.jsp");
            }else {
        
                resp.getWriter().write("<h2>failed</h2>");
            }
    
        }
    
        public void search(HttpServletRequest req, HttpServletResponse resp) throws IOException {
        
            resp.setContentType("text/html;charset=GBK");
            resp.setContentType("text/html");
            String name = req.getParameter("name");
            User user1 = userService.selectByName(name);
            if (user1 != null){
        
                resp.getWriter().write("<h1>用户名："+user1.getName()+"<h1><h1>密码："+user1.getPassword()+"<h1><h1>年龄："+user1.getAge());
            }else {
        
                resp.getWriter().write("失败!");
            }
        }
    
    }

## 添加Tomcat ##

下载完Tomcat后，回到页面，点击右上角的Add Configuration  
![在这里插入图片描述][20200704002237300.png]  
进入页面后点击左上角的＋  
![在这里插入图片描述][20200704002322426.png]  
选择Tomcat Server下的Local  
![选择下载路径][20200704002410276.png]  
进入Deployment  
![在这里插入图片描述][20200704002455274.png]  
点击下方的fix自动加入war包  
将Application context内的地址删除，然后应用即可  
![在这里插入图片描述][20200704002545383.png]

# 运行结果 #

最后让我们来看一下运行结果  
先让我们来看看数据库内的数据  
![在这里插入图片描述][20200704002840620.png]  
输入数据库内存在的账户密码  
![在这里插入图片描述][20200704002903292.png]  
![在这里插入图片描述][20200704002941896.png]  
接下来跳转到注册页面  
![在这里插入图片描述][20200704003009562.png]  
输入一条数据库内没有的记录  
![在这里插入图片描述][20200704010236384.png]  
点击注册后会跳转到主页，数据库会多出一条添加的数据  
![在这里插入图片描述][20200704010338706.png]  
然后门来到查询页面，输入数据库中的一条数据内容  
![在这里插入图片描述][20200704010424935.png]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p2ZXJf_size_16_color_FFFFFF_t_70 4]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p2ZXJf_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20200703234741816.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p2ZXJf,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p2ZXJf_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20200703234840952.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p2ZXJf,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p2ZXJf_size_16_color_FFFFFF_t_70 2]: https://img-blog.csdnimg.cn/20200703235040302.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p2ZXJf,size_16,color_FFFFFF,t_70
[20200703235411831.png]: https://img-blog.csdnimg.cn/20200703235411831.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p2ZXJf_size_16_color_FFFFFF_t_70 3]: https://img-blog.csdnimg.cn/20200703235935294.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p2ZXJf,size_16,color_FFFFFF,t_70
[20200704000013573.png]: https://img-blog.csdnimg.cn/20200704000013573.png
[20200704002237300.png]: https://img-blog.csdnimg.cn/20200704002237300.png
[20200704002322426.png]: https://img-blog.csdnimg.cn/20200704002322426.png
[20200704002410276.png]: https://img-blog.csdnimg.cn/20200704002410276.png
[20200704002455274.png]: https://img-blog.csdnimg.cn/20200704002455274.png
[20200704002545383.png]: https://img-blog.csdnimg.cn/20200704002545383.png
[20200704002840620.png]: https://img-blog.csdnimg.cn/20200704002840620.png
[20200704002903292.png]: https://img-blog.csdnimg.cn/20200704002903292.png
[20200704002941896.png]: https://img-blog.csdnimg.cn/20200704002941896.png
[20200704003009562.png]: https://img-blog.csdnimg.cn/20200704003009562.png
[20200704010236384.png]: https://img-blog.csdnimg.cn/20200704010236384.png
[20200704010338706.png]: https://img-blog.csdnimg.cn/20200704010338706.png
[20200704010424935.png]: https://img-blog.csdnimg.cn/20200704010424935.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p2ZXJf_size_16_color_FFFFFF_t_70 4]: https://img-blog.csdnimg.cn/20200704010438972.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p2ZXJf,size_16,color_FFFFFF,t_70