基于javaweb写一个学生管理系统

好的，下面是一个简单的JavaWeb学生管理系统的实现过程：

1. 确定系统需求和功能模块，例如学生信息管理、课程管理、成绩管理等。

2. 创建数据库，建立学生表、课程表和成绩表，并建立表之间的关系。

3. 使用JSP和Servlet技术建立前端页面和后端控制器，实现用户输入数据、查询数据、修改数据和删除数据等操作。

4. 使用JDBC技术连接数据库，实现数据的增删改查操作。

5. 使用MVC模式进行代码的分层，将业务逻辑、数据访问、视图显示分开，使系统具有良好的可维护性。

下面是一个简单的示例代码：

1. 学生实体类：

public class Student {
    private int id; // 学生ID
    private String name; // 学生姓名
    private int age; // 学生年龄

    // 构造方法
    public Student(int id, String name, int age) {
        this.id = id;
        this.name = name;
        this.age = age;
    }

    // getter和setter方法
    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 int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

2. 数据库连接工具类：

public class DBUtil {
    private static final String URL = "jdbc:mysql://localhost:3306/student"; // 数据库连接地址
    private static final String USERNAME = "root"; // 数据库用户名
    private static final String PASSWORD = "123456"; // 数据库密码

    // 获取数据库连接
    public static Connection getConnection() throws SQLException, ClassNotFoundException {
        Class.forName("com.mysql.jdbc.Driver"); // 加载数据库驱动
        return DriverManager.getConnection(URL, USERNAME, PASSWORD); // 获取数据库连接
    }

    // 关闭数据库连接
    public static void closeConnection(Connection conn, Statement stmt, ResultSet rs) throws SQLException {
        if (rs != null) {
            rs.close();
        }
        if (stmt != null) {
            stmt.close();
        }
        if (conn != null) {
            conn.close();
        }
    }
}

3. 学生DAO类：

public class StudentDAO {
    // 添加学生信息
    public void add(Student student) throws SQLException, ClassNotFoundException {
        Connection conn = DBUtil.getConnection();
        PreparedStatement pstmt = conn.prepareStatement("insert into student(id, name, age) values (?, ?, ?)");
        pstmt.setInt(1, student.getId());
        pstmt.setString(2, student.getName());
        pstmt.setInt(3, student.getAge());
        pstmt.executeUpdate();
        DBUtil.closeConnection(conn, pstmt, null);
    }

    // 删除学生信息
    public void delete(int id) throws SQLException, ClassNotFoundException {
        Connection conn = DBUtil.getConnection();
        PreparedStatement pstmt = conn.prepareStatement("delete from student where id = ?");
        pstmt.setInt(1, id);
        pstmt.executeUpdate();
        DBUtil.closeConnection(conn, pstmt, null);
    }

    // 修改学生信息
    public void update(Student student) throws SQLException, ClassNotFoundException {
        Connection conn = DBUtil.getConnection();
        PreparedStatement pstmt = conn.prepareStatement("update student set name = ?, age = ? where id = ?");
        pstmt.setString(1, student.getName());
        pstmt.setInt(2, student.getAge());
        pstmt.setInt(3, student.getId());
        pstmt.executeUpdate();
        DBUtil.closeConnection(conn, pstmt, null);
    }

    // 查询所有学生信息
    public List<Student> findAll() throws SQLException, ClassNotFoundException {
        List<Student> students = new ArrayList<>();
        Connection conn = DBUtil.getConnection();
        Statement stmt = conn.createStatement();
        ResultSet rs = stmt.executeQuery("select * from student");
        while (rs.next()) {
            Student student = new Student(rs.getInt("id"), rs.getString("name"), rs.getInt("age"));
            students.add(student);
        }
        DBUtil.closeConnection(conn, stmt, rs);
        return students;
    }

    // 根据ID查询学生信息
    public Student findById(int id) throws SQLException, ClassNotFoundException {
        Student student = null;
        Connection conn = DBUtil.getConnection();
        PreparedStatement pstmt = conn.prepareStatement("select * from student where id = ?");
        pstmt.setInt(1, id);
        ResultSet rs = pstmt.executeQuery();
        if (rs.next()) {
            student = new Student(rs.getInt("id"), rs.getString("name"), rs.getInt("age"));
        }
        DBUtil.closeConnection(conn, pstmt, rs);
        return student;
    }
}

4. 控制器Servlet类：

@WebServlet("/student")
public class StudentServlet extends HttpServlet {
    private StudentDAO studentDAO;

    public void init() {
        studentDAO = new StudentDAO();
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String action = request.getParameter("action");
        if (action == null) {
            action = "list";
        }
        switch (action) {
            case "list":
                list(request, response);
                break;
            case "add":
                add(request, response);
                break;
            case "delete":
                delete(request, response);
                break;
            case "edit":
                edit(request, response);
                break;
            case "update":
                update(request, response);
                break;
        }
    }

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

    // 列出所有学生信息
    private void list(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        try {
            List<Student> students = studentDAO.findAll();
            request.setAttribute("students", students);
            request.getRequestDispatcher("/list.jsp").forward(request, response);
        } catch (SQLException | ClassNotFoundException e) {
            e.printStackTrace();
        }
    }

    // 添加学生信息
    private void add(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        int id = Integer.parseInt(request.getParameter("id"));
        String name = request.getParameter("name");
        int age = Integer.parseInt(request.getParameter("age"));
        Student student = new Student(id, name, age);
        try {
            studentDAO.add(student);
            response.sendRedirect("student?action=list");
        } catch (SQLException | ClassNotFoundException e) {
            e.printStackTrace();
        }
    }

    // 删除学生信息
    private void delete(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        int id = Integer.parseInt(request.getParameter("id"));
        try {
            studentDAO.delete(id);
            response.sendRedirect("student?action=list");
        } catch (SQLException | ClassNotFoundException e) {
            e.printStackTrace();
        }
    }

    // 修改学生信息
    private void edit(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        int id = Integer.parseInt(request.getParameter("id"));
        try {
            Student student = studentDAO.findById(id);
            request.setAttribute("student", student);
            request.getRequestDispatcher("/edit.jsp").forward(request, response);
        } catch (SQLException | ClassNotFoundException e) {
            e.printStackTrace();
        }
    }

    // 更新学生信息
    private void update(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        int id = Integer.parseInt(request.getParameter("id"));
        String name = request.getParameter("name");
        int age = Integer.parseInt(request.getParameter("age"));
        Student student = new Student(id, name, age);
        try {
            studentDAO.update(student);
            response.sendRedirect("student?action=list");
        } catch (SQLException | ClassNotFoundException e) {
            e.printStackTrace();
        }
    }
}

5. 前端页面：

list.jsp：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>学生管理系统</title>
</head>
<body>
    <h1>学生列表</h1>
    <a href="add.jsp">添加学生</a>
    <table border="1">
        <tr>
            <th>ID</th>
            <th>姓名</th>
            <th>年龄</th>
            <th>操作</th>
        </tr>
        <c:forEach var="student" items="${students}">
            <tr>
                <td><c:out value="${student.id}"/></td>
                <td><c:out value="${student.name}"/></td>
                <td><c:out value="${student.age}"/></td>
                <td>
                    <a href="student?action=edit&id=${student.id}">修改</a>
                    <a href="student?action=delete&id=${student.id}">删除</a>
                </td>
            </tr>
        </c:forEach>
    </table>
</body>
</html>

add.jsp：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>添加学生信息</title>
</head>
<body>
    <h1>添加学生信息</h1>
    <form action="student?action=add" method="post">
        <label>ID：</label>
        <input type="text" name="id"><br>
        <label>姓名：</label>
        <input type="text" name="name"><br>
        <label>年龄：</label>
        <input type="text" name="age"><br>
        <input type="submit" value="提交">
    </form>
</body>
</html>

edit.jsp：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>修改学生信息</title>
</head>
<body>
    <h1>修改学生信息</h1>
    <form action="student?action=update" method="post">
        <label>ID：</label>
        <input type="text" name="id" value="${student.id}" readonly><br>
        <label>姓名：</label>
        <input type="text" name="name" value="${student.name}"><br>
        <label>年龄：</label>
        <input type="text" name="age" value="${student.age}"><br>
        <input type="submit" value="提交">
    </form>
</body>
</html>

以上就是一个简单的JavaWeb学生管理系统的实现过程。当然，这只是一个基础的示例，实际开发中还需要考虑数据校验、权限控制、分页显示等功能。