能帮我写出一个简单的javaweb学生考勤管理系统的所需代码嘛

当然可以，以下是一个简单的JavaWeb学生考勤管理系统的代码示例：

1. 创建数据库表

考勤表：

CREATE TABLE attendance (
  id INT(11) NOT NULL AUTO_INCREMENT,
  student_id INT(11) NOT NULL,
  attendance_date DATE NOT NULL,
  status INT(1) NOT NULL,
  PRIMARY KEY (id)
);

学生表：

CREATE TABLE student (
  id INT(11) NOT NULL AUTO_INCREMENT,
  name VARCHAR(50) NOT NULL,
  address VARCHAR(255) NOT NULL,
  PRIMARY KEY (id)
);

2. 创建JavaBean类

Attendance.java:

public class Attendance {
    private int id;
    private int studentId;
    private Date attendanceDate;
    private int status;
    // getter and setter
}

Student.java:

public class Student {
    private int id;
    private String name;
    private String address;
    // getter and setter
}

3. 创建Dao类

AttendanceDao.java:

public class AttendanceDao {
    private Connection conn;

    public AttendanceDao(Connection conn) {
        this.conn = conn;
    }

    public void addAttendance(Attendance attendance) throws SQLException {
        String sql = "INSERT INTO attendance (student_id, attendance_date, status) VALUES (?, ?, ?)";
        try (PreparedStatement pstmt = conn.prepareStatement(sql)) {
            pstmt.setInt(1, attendance.getStudentId());
            pstmt.setDate(2, new java.sql.Date(attendance.getAttendanceDate().getTime()));
            pstmt.setInt(3, attendance.getStatus());
            pstmt.executeUpdate();
        }
    }

    public List<Attendance> getAttendanceList() throws SQLException {
        List<Attendance> attendanceList = new ArrayList<>();
        String sql = "SELECT * FROM attendance";
        try (PreparedStatement pstmt = conn.prepareStatement(sql)) {
            try (ResultSet rs = pstmt.executeQuery()) {
                while (rs.next()) {
                    Attendance attendance = new Attendance();
                    attendance.setId(rs.getInt("id"));
                    attendance.setStudentId(rs.getInt("student_id"));
                    attendance.setAttendanceDate(rs.getDate("attendance_date"));
                    attendance.setStatus(rs.getInt("status"));
                    attendanceList.add(attendance);
                }
            }
        }
        return attendanceList;
    }
}

StudentDao.java:

public class StudentDao {
    private Connection conn;

    public StudentDao(Connection conn) {
        this.conn = conn;
    }

    public void addStudent(Student student) throws SQLException {
        String sql = "INSERT INTO student (name, address) VALUES (?, ?)";
        try (PreparedStatement pstmt = conn.prepareStatement(sql)) {
            pstmt.setString(1, student.getName());
            pstmt.setString(2, student.getAddress());
            pstmt.executeUpdate();
        }
    }

    public List<Student> getStudentList() throws SQLException {
        List<Student> studentList = new ArrayList<>();
        String sql = "SELECT * FROM student";
        try (PreparedStatement pstmt = conn.prepareStatement(sql)) {
            try (ResultSet rs = pstmt.executeQuery()) {
                while (rs.next()) {
                    Student student = new Student();
                    student.setId(rs.getInt("id"));
                    student.setName(rs.getString("name"));
                    student.setAddress(rs.getString("address"));
                    studentList.add(student);
                }
            }
        }
        return studentList;
    }
}

4. 创建Servlet类

添加学生Servlet：

@WebServlet("/add_student")
public class AddStudentServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String name = req.getParameter("name");
        String address = req.getParameter("address");
        Student student = new Student();
        student.setName(name);
        student.setAddress(address);
        try {
            Connection conn = DBUtil.getConnection();
            StudentDao studentDao = new StudentDao(conn);
            studentDao.addStudent(student);
            DBUtil.closeConnection(conn);
            resp.sendRedirect("index.jsp");
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

考勤记录Servlet：

@WebServlet("/attendance_list")
public class AttendanceListServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        try {
            Connection conn = DBUtil.getConnection();
            AttendanceDao attendanceDao = new AttendanceDao(conn);
            List<Attendance> attendanceList = attendanceDao.getAttendanceList();
            req.setAttribute("attendanceList", attendanceList);
            DBUtil.closeConnection(conn);
            req.getRequestDispatcher("attendance_list.jsp").forward(req, resp);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

5. 创建JSP页面

index.jsp:

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>学生考勤管理系统</title>
</head>
<body>
    <form method="post" action="add_student">
        <input type="text" name="name" placeholder="请输入学生姓名">
        <input type="text" name="address" placeholder="请输入学生地址">
        <button type="submit">添加</button>
    </form>
    <br>
    <a href="attendance_list">查看考勤记录</a>
</body>
</html>

attendance_list.jsp:

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>考勤记录</title>
</head>
<body>
    <table border="1">
        <tr>
            <th>ID</th>
            <th>学生ID</th>
            <th>考勤时间</th>
            <th>状态</th>
        </tr>
        <c:forEach var="attendance" items="${attendanceList}">
            <tr>
                <td>${attendance.id}</td>
                <td>${attendance.studentId}</td>
                <td>${attendance.attendanceDate}</td>
                <td>${attendance.status}</td>
            </tr>
        </c:forEach>
    </table>
</body>
</html>

以上是一个简单的JavaWeb学生考勤管理系统的示例代码，仅供参考。完整的代码需要根据实际情况进行修改和完善。