Java、JavaWeb、数据库-图书管理系统

这一章主要是把上一章写在网页里的java 代码从网页中分离出来，放在专门的servlet类中。每一个servlet类对应一个数据库的表。

规范性问题：

1、dao包存放有关数据库的信息：BaseDao包就放数据库加载驱动和增删改和关闭资源；而其他的每一个表名对应一个相应名字的dao包，写数据库的增删改查操作；

2、servlet包专存放和网页有关的代码，把网页传来的参数进行接受，同时调用相应名字的dao类中的方法，返回到相应的页面。

3、untity包专门放对应表格的实体类

4、test包专门放测试的方法，单元测试等。

整合前面的的学生管理系统，重构一个图书管理系统，要求规范性，且网页中不在出现java代码，都放在servlet类中

在写代码前先建好相应的包，并且导入数据库的jar包，web的jar包，还有tomcat的配置，以及在数据库编辑软件navicat建好相应的数据表。

图书管理系统的运行截图：左上方两个表在数据库建好

登录界面展示：

注册界面展示：

各种功能展示：

一、代码：

BaseDao:

package com.zyl.dao;

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

/**
 * @className: BaseDao
 * @author: Zyl
 * @date: 2024/12/3 16:49
 * @Version: 1.0
 * @description:
 */

public class BaseDao {
     Connection connection= null;
     PreparedStatement ps=null;
     ResultSet resultSet = null;

     String url = "jdbc:mysql://localhost:3306/jdbctest";
     String username = "root";
     String password = "root";
     String DriverName="com.mysql.jdbc.Driver";
    //加载驱动，获取连接，连接数据库
    public  void connection()throws  Exception{
        Class.forName(DriverName);
        connection = DriverManager.getConnection(url, username, password);
    }
    //针对增删改的方法,没有查询的功能
    public int edit(String sql,Object... params) {

        try {
            connection();
            ps = connection.prepareStatement(sql);
            for (int i = 0; i < params.length; i++) {
                ps.setObject(i + 1, params[i]);
            }
            int row = ps.executeUpdate();
            return row;
        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            closeAll();
        }

    }
    //关闭所有的资源
    public  void closeAll(){
        try {
            if(resultSet!=null){
                resultSet.close();
            }
            if(ps!=null){
                ps.close();
            }
            if(connection!=null){
                connection.close();
            }
        }catch (Exception e){
            throw new RuntimeException(e);
        }
    }

}

BookDao:

package com.zyl.dao;

import com.zyl.untity.Book;

import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;

/**
 * @className: BookDao
 * @author: Zyl
 * @date: 2024/12/6 10
 * @Version: 1.0
 * @description:
 */

public class BookDao extends BaseDao{
//查询所有的图书
    public ArrayList<Book> selectAll(){
        ArrayList<Book> list=new ArrayList<Book>();
        try {
            connection();
            String sql="select * from tbl_book";

            ps = connection.prepareStatement(sql);
            resultSet = ps.executeQuery();
            while (resultSet.next()){
                int id=resultSet.getInt("id");
                String name=resultSet.getString("name");
                double price=resultSet.getDouble("price");
                String publisher=resultSet.getString("publisher");
                Book book =new Book();
                book.setId(id);
                book.setName(name);
                book.setPrice(price);
                book.setPublisher(publisher);
                list.add(book);
            }
            return list;
        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            closeAll();
        }


    }
    public int  delete(int id){
        String sql = "delete from  tbl_book where id=?";
        //d调用父类BaseDao 的edit()方法   增删改操作;;;;;;
        int edit = edit(sql,id);
        return  edit;
    }
    public Book findById(int id){
        Book book =null;

        try {
            String sql = "select * from tbl_book where id=?";
            connection();
            ps = connection.prepareStatement(sql);
            ps.setInt(1,id);
            resultSet = ps.executeQuery();
            while (resultSet.next()){
                int id1=resultSet.getInt("id");
                String name=resultSet.getString("name");
                double price=resultSet.getDouble("price");
                String publisher=resultSet.getString("publisher");
                book=new Book(id1,name,price,publisher);
            }
            return book;
        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            closeAll();
        }
    }
    public int  update(int id,String name,double price,String publisher ){
        String sql = "update  tbl_book set name=?,price=?,publisher=?where id=?";
        //d调用父类BaseDao 的edit()方法   增删改操作;;;;;;
        int edit = edit(sql,name,price,publisher,id);
        return  edit;
    }
    public int  insert(String name,double price,String publisher ){
        String sql = "insert into tbl_book(name,price,publisher) values(?,?,?)";
        //d调用父类BaseDao 的edit()方法   增删改操作;;;;;;
        int edit = edit(sql,name,price,publisher);
        return  edit;
    }


}

UserDao:

package com.zyl.dao;

import com.zyl.untity.User;

/**
 * @className: UserDao
 * @author: Zyl
 * @date: 2024/12/6 10:15
 * @Version: 1.0
 * @description:
 */

public class UserDao extends BaseDao{

 public User login(String username, String password){
     User user=null;
     try {
         String sql="select * from tbl_user where username=? and password=?";
         connection();
         ps = connection.prepareStatement(sql);
         ps.setObject(1,username);
         ps.setObject(2,password);
         resultSet = ps.executeQuery();
         while(resultSet.next()){
             int id = resultSet.getInt("id");
             String username1 = resultSet.getString("username");
             String password1 = resultSet.getString("password");
             String realname = resultSet.getString("realname");
             int age = resultSet.getInt("age");
            // user=new User(username1,id,password1,realname,age);
             user=new User();
             user.setId(id);
             user.setUsername(username1);
             user.setAge(age);
             user.setPassword(password1);
             user.setRealname(realname);
         }

     } catch (Exception e) {
         throw new RuntimeException(e);
     } finally {
         closeAll();
     }
     return user;
   }

public int  add(String username, String password){
    String sql="insert into tbl_user(username,password) values(?,?)";
    int i=edit(sql,username,password);
    return  i;

}




 }

BookServlet:

package com.zyl.servlet;

import com.zyl.dao.BookDao;
import com.zyl.untity.Book;

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;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;

/**
 * @className: BookServlet
 * @author: Zyl
 * @date: 2024/12/6 10:26
 * @Version: 1.0
 * @description:
 */
@WebServlet(urlPatterns = "/book")
public class BookServlet extends HttpServlet {
    private BookDao bookDao = new BookDao();
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("UTF-8");
        String method = req.getParameter("method");
        if("delete".equals(method)){
            delete(req,resp);
        }else if("getById".equals(method)){
            selectById(req,resp);
        }else if("update".equals(method)){
            update(req,resp);
        }else if("insert".equals(method)){
            insert(req,resp);
        }
        else{
            selectAll(req,resp);
        }



    }
    public void insert(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //获取参数
        String name = req.getParameter("name");
        double price = Double.parseDouble(req.getParameter("price"));
        String publisher = req.getParameter("publisher");
        BookDao bookDao = new BookDao();
        int i = bookDao.insert(name, price, publisher);
        if(i>0){
            resp.sendRedirect("/book");
        }

    }

    private void selectById(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //获取id
        String id = req.getParameter("id");
        //创建对象
        BookDao bookDao = new BookDao();
        Book b = bookDao.findById(Integer.parseInt(id));
        req.setAttribute("book",b);
        req.getRequestDispatcher("/edit.jsp").forward(req,resp);


    }

    public void selectAll(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException{

        BookDao bookDao = new BookDao();
        ArrayList<Book> books = bookDao.selectAll();
        req.setAttribute("books",books);
        req.getRequestDispatcher("/index.jsp").forward(req,resp);
    }
    public void delete(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException{
        String id = req.getParameter("id");//获取id
        BookDao bookDao = new BookDao();//创建对象
        int delete = bookDao.delete(Integer.parseInt(id));
        if(delete>0){
            resp.sendRedirect("/book");
        }

    }
    public void update(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException{
        //获取参数
        String id = req.getParameter("id");
        String name = req.getParameter("name");
        String  price = req.getParameter("price");
        String publisher = req.getParameter("publisher");
        //先判断在创建对象并调用方法
        if(id!=null&&!id.equals("")&&name!=null&&!name.equals("")&&price!=null&&!price.equals("")&&publisher!=null&&!publisher.equals("")){
            BookDao b=new BookDao();
            int i=b.update(Integer.parseInt(id),name, Double.parseDouble(price),publisher);
            if(i>0){
                resp.sendRedirect("/book");
            }
        }




    }
}

UserServlet:

package com.zyl.servlet;

import com.zyl.dao.UserDao;
import com.zyl.untity.User;

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 javax.servlet.http.HttpSession;
import java.io.IOException;
import java.io.UnsupportedEncodingException;

/**
 * @className: UserServlet
 * @author: Zyl
 * @date: 2024/12/6 10:25
 * @Version: 1.0
 * @description:
 */
@WebServlet(urlPatterns = "/user")
public class UserServlet extends HttpServlet {
    private UserDao userDao=new UserDao();//对象
    @Override
    public void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf-8");

        String method = req.getParameter("method");
        if ("login".equals(method)) {
            login(req, resp);
        } else if ("register".equals(method)) {
            register(req, resp);
        } else if ("exit".equals(method)){
            exit(req, resp);

        }
    }
    public void exit(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException  {
        HttpSession session=req.getSession();
       //获取session，判断是否登录，登录了就删除session，并跳转回登录页面

            session.removeAttribute("user");
            resp.sendRedirect("/login.jsp");
    }

    public void login(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String username = req.getParameter("username");
        String password = req.getParameter("password");
        UserDao userDao = new UserDao();
        User user = userDao.login(username, password);
        if (user!= null) {
            //保存到session会话
            req.getSession().setAttribute("user", user);
            //跳转--成功页面【展示所有图书】
            resp.sendRedirect("/book");
        } else {
            //跳转到登录页面
            req.setAttribute("error", "<font color='red'>账号或密码错误</font>");
            req.getRequestDispatcher("/login.jsp").forward(req, resp);//转发跳转.必须转发跳转
        }


    }

    public void register(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        // 获取表单数据
        String username = req.getParameter("username");
        String password = req.getParameter("password");
        String confirmPassword = req.getParameter("confirmPassword");
        System.out.println(1222);
        // 初始化消息变量
        String message = "";
        String messageType = "";

        // 检查密码是否一致
        if (!password.equals(confirmPassword)) {
            message = "两次输入的密码不一致，请重新输入。";
            messageType = "error-message";
        } else {
            // 创建 UserDao 实例
            UserDao userDao = new UserDao();
            // 检查用户名和密码是否同时存在
            if (userDao.login(username, password) != null) {
                message = "该用户名和密码已被注册过。";
                messageType = "error-message";
            } else {
                // 调用 add 方法添加学生
                int result = userDao.add(username, password);

                if (result > 0) {
                    message = "注册成功！";
                    messageType = "success-message";
                } else {
                    message = "注册失败，请重试。";
                    messageType = "error-message";
                }
            }
        }
        // 将消息存储到请求属性中

        req.setAttribute("message", message);
        req.setAttribute("messageType", messageType);


        // 转发到 register.jsp 显示消息
        req.getRequestDispatcher("/register.jsp").forward(req, resp);
    }

}

二、网页代码：

bookadd.jsp:

<%--
  Created by IntelliJ IDEA.
  User: 
  Date: 2024/12/7
  Time: 16:21
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <title>添加图书界面</title>
    <style>
        body {
            font-family: Arial, sans-serif;
            background-color: #f4f4f9;
            display: flex;
            justify-content: center;
            align-items: center;
            height: 100vh;
            margin: 0;
        }
        .container {
            background-color: #fff;
            padding: 20px;
            border-radius: 8px;
            box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
            width: 80%;
            max-width: 400px;
            text-align: center;
        }
        .container h1 {
            margin-bottom: 20px;
        }
        .form-group {
            margin-bottom: 15px;
            text-align: left;
        }
        .form-group label {
            display: block;
            margin-bottom: 5px;
            font-weight: bold;
        }
        .form-group input {
            width: 100%;
            padding: 8px;
            box-sizing: border-box;
            border: 1px solid #ccc;
            border-radius: 4px;
        }
        .button-container {
            margin-top: 20px;
        }
        .button-container button {
            padding: 10px 20px;
            border: none;
            border-radius: 4px;
            cursor: pointer;
            background-color: #007bff;
            color: white;
            font-size: 16px;
        }
        .button-container button:hover {
            background-color: #0056b3;
        }
        .error-message {
            color: red;
            margin-bottom: 15px;
        }
        .success-message {
            color: green;
            margin-bottom: 15px;
        }
    </style>
</head>
<body>
<div class="container">
    <h1>添加图书界面</h1>
    <c:if test="${sessionScope.user==null}">
        <c:redirect url="/login.jsp"/>
    </c:if>
    <form action="/book?method=insert" method="post">
        <div class="form-group">
            <label for="name">书名：</label>
            <input type="text" id="name" name="name" placeholder="请输入书名" required/>
        </div>
        <div class="form-group">
            <label for="price">价格：</label>
            <input type="number" id="price" name="price" placeholder="请输入价格" step="0.01" required/>
        </div>
        <div class="form-group">
            <label for="publisher">出版社：</label>
            <input type="text" id="publisher" name="publisher" placeholder="请输入出版社" required/>
        </div>
        <div class="button-container">
            <button type="submit">添加</button>
        </div>
    </form>
</div>
</body>
</html>

edit.jsp:

<%--
  Created by IntelliJ IDEA.
  User: 
  Date: 2024/12/7
  Time: 15:37
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <title>编辑图书</title>
    <style>
        body {
            font-family: Arial, sans-serif;
            background-color: #f4f4f9;
            display: flex;
            justify-content: center;
            align-items: center;
            height: 100vh;
            margin: 0;
        }
        .container {
            background-color: #fff;
            padding: 20px;
            border-radius: 8px;
            box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
            width: 80%;
            max-width: 400px;
            text-align: center;
        }
        .container h1 {
            margin-bottom: 20px;
        }
        .form-group {
            margin-bottom: 15px;
            text-align: left;
        }
        .form-group label {
            display: block;
            margin-bottom: 5px;
            font-weight: bold;
        }
        .form-group input {
            width: 100%;
            padding: 8px;
            box-sizing: border-box;
            border: 1px solid #ccc;
            border-radius: 4px;
        }
        .button-container {
            margin-top: 20px;
        }
        .button-container button {
            padding: 10px 20px;
            border: none;
            border-radius: 4px;
            cursor: pointer;
            background-color: #007bff;
            color: white;
            font-size: 16px;
        }
        .button-container button:hover {
            background-color: #0056b3;
        }
        .error-message {
            color: red;
            margin-bottom: 15px;
        }
        .success-message {
            color: green;
            margin-bottom: 15px;
        }
    </style>
</head>
<body>
<div class="container">
    <h1>编辑图书</h1>
    <c:if test="${sessionScope.user==null}">
        <c:redirect url="/login.jsp"/>
    </c:if>
    <form action="/book?method=update" method="post">
        <div class="form-group">
            <label for="id">ID：</label>
            <input type="text" id="id" name="id" value="${book.getId()}" readonly/>
        </div>
        <div class="form-group">
            <label for="name">书名：</label>
            <input type="text" id="name" name="name" placeholder="请输入书名" value="${book.getName()}" required/>
        </div>
        <div class="form-group">
            <label for="price">价格：</label>
            <input type="number" id="price" name="price" placeholder="请输入价格" value="${book.getPrice()}" step="0.01" required/>
        </div>
        <div class="form-group">
            <label for="publisher">出版社：</label>
            <input type="text" id="publisher" name="publisher" placeholder="请输入出版社" value="${book.getPublisher()}" required/>
        </div>
        <div class="button-container">
            <button type="submit">立即修改</button>
        </div>
    </form>
</div>
</body>
</html>

index.jsp:

<%@ page import="com.zyl.untity.User" %><%--
  Created by IntelliJ IDEA.
  User: ${zyl}
  Date: 2024/12/6
  Time: 10:12
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
  <title>图书首页</title>
  <style>
    body {
      font-family: Arial, sans-serif;
      background-color: #f4f4f9;
      display: flex;
      justify-content: center;
      align-items: center;
      height: 100vh;
      margin: 0;
    }
    .container {
      background-color: #fff;
      padding: 20px;
      border-radius: 8px;
      box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
      width: 80%;
      max-width: 800px;
      text-align: center;
    }
    .container h1 {
      margin-bottom: 20px;
    }
    .button-container {
      margin-bottom: 20px;
    }
    .button-container button {
      margin: 0 10px;
      padding: 10px 20px;
      border: none;
      border-radius: 4px;
      cursor: pointer;
      background-color: #007bff;
      color: white;
      font-size: 16px;
    }
    .button-container button:hover {
      background-color: #0056b3;
    }
    table {
      width: 100%;
      border-collapse: collapse;
      margin-top: 20px;
    }
    th, td {
      border: 1px solid #ddd;
      padding: 8px;
      text-align: left;
    }
    th {
      background-color: #f2f2f2;
    }
    tr:nth-child(even) {
      background-color: #f9f9f9;
    }
    tr:hover {
      background-color: #f1f1f1;
    }
    a {
      margin: 0 5px;
      text-decoration: none;
      color: #007bff;
    }
    a:hover {
      text-decoration: underline;
    }
  </style>
</head>
<body>
<c:if test="${sessionScope.user == null}">
  <c:redirect url="/login.jsp"/>
</c:if>
<div class="container">
  <h1>欢迎${sessionScope.user.realname}访问图书管理系统</h1>
  <div class="button-container">
    <button οnclick="location.href='/bookadd.jsp'">添加</button>
    <button οnclick="location.href='/user?method=exit'">退出</button>
  </div>
  <table>
    <tr>
      <th>编号</th>
      <th>姓名</th>
      <th>价格</th>
      <th>出版社</th>
      <th>操作</th>
    </tr>
    <c:forEach items="${requestScope.books}" var="b">
      <tr>
        <td>${b.id}</td>
        <td>${b.name}</td>
        <td>${b.price}</td>
        <td>${b.publisher}</td>
        <td>
          <a οnclick="del(${b.id})">删除</a>
          <a href="/book?method=getById&id=${b.id}">修改</a>
        </td>
      </tr>
    </c:forEach>
  </table>
</div>
<script>
  function del(id) {
    var b = confirm("是否删除该记录?");
    if (b) {
      location.href = "/book?method=delete&id=" + id;
    }
  }
</script>
</body>
</html>

login.jsp:

<%--
  Created by IntelliJ IDEA.
  User: 
  Date: 2024/12/6
  Time: 10:50
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>登录界面</title>
    <style>
        body {
            font-family: Arial, sans-serif;
            background-color: #f4f4f9;
            display: flex;
            justify-content: center;
            align-items: center;
            height: 100vh;
            margin: 0;
        }
        .login-container {
            background-color: #fff;
            padding: 20px;
            border-radius: 8px;
            box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
            width: 300px;
            text-align: center;
        }
        .login-container h2 {
            margin-bottom: 20px;
        }
        .login-container input[type="text"],
        .login-container input[type="password"] {
            width: calc(100% - 22px);
            padding: 10px;
            margin: 10px 0;
            border: 1px solid #ccc;
            border-radius: 4px;
        }
        .login-container input[type="submit"],
        .login-container input[type="button"] {
            width: calc(100% - 22px);
            padding: 10px;
            margin: 10px 0;
            border: none;
            border-radius: 4px;
            cursor: pointer;
            background-color: #007bff;
            color: white;
            font-size: 16px;
        }
        .login-container input[type="submit"]:hover,
        .login-container input[type="button"]:hover {
            background-color: #0056b3;
        }
        .error-message {
            color: red;
            margin-bottom: 10px;
        }
    </style>
</head>
<body>
<div class="login-container">
    <h2>登录界面</h2>
    <div class="error-message">${error}</div>

    <form action="/user?method=login" method="post">
        <input type="text" name="username" placeholder="账号"/><br>
        <input type="password" name="password" placeholder="密码"/><br>
        <input type="submit" value="立即登录"/>
        <input type="button" value="注册" οnclick="location.href='register.jsp'"/>
    </form>
</div>
</body>
</html>

register.jsp:

<%--
  Created by IntelliJ IDEA.
  User: 
  Date: 2024/12/7
  Time: 10:56
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <title>注册界面</title>
    <style>
        body {
            font-family: Arial, sans-serif;
            background-color: #f4f4f9;
            display: flex;
            justify-content: center;
            align-items: center;
            height: 100vh;
            margin: 0;
        }
        .container {
            background-color: #fff;
            padding: 20px;
            border-radius: 8px;
            box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
            width: 80%;
            max-width: 400px;
            text-align: center;
        }
        .container h1 {
            margin-bottom: 20px;
        }
        .form-group {
            margin-bottom: 15px;
            text-align: left;
        }
        .form-group label {
            display: block;
            margin-bottom: 5px;
            font-weight: bold;
        }
        .form-group input {
            width: 100%;
            padding: 8px;
            box-sizing: border-box;
            border: 1px solid #ccc;
            border-radius: 4px;
        }
        .button-container {
            margin-top: 20px;
        }
        .button-container button {
            padding: 10px 20px;
            border: none;
            border-radius: 4px;
            cursor: pointer;
            background-color: #007bff;
            color: white;
            font-size: 16px;
        }
        .button-container button:hover {
            background-color: #0056b3;
        }
        .error-message {
            color: red;
            margin-bottom: 15px;
        }
        .success-message {
            color: green;
            margin-bottom: 15px;
        }
        .login-link {
            margin-top: 15px;
            font-size: 14px;
        }
        .login-link a {
            color: #007bff;
            text-decoration: none;
        }
        .login-link a:hover {
            text-decoration: underline;
        }
    </style>
</head>
<body>
<div class="container">
    <h1>注册界面</h1>
    <c:if test="${not empty message}">
        <div class="${messageType}">${message}</div>
    </c:if>
    <form action="/user?method=register" method="post">
        <div class="form-group">
            <label for="username">账号：</label>
            <input type="text" id="username" name="username" required>
        </div>
        <div class="form-group">
            <label for="password">密码：</label>
            <input type="password" id="password" name="password" required>
        </div>
        <div class="form-group">
            <label for="confirmPassword">确认密码：</label>
            <input type="password" id="confirmPassword" name="confirmPassword" required>
        </div>
        <div class="button-container">
            <button type="submit">注册</button>
        </div>
        <div class="login-link">
            <a href="login.jsp">已有账号，立即登录</a>
        </div>
    </form>
</div>
</body>
</html>