/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package servlet;

import dao.DatabaseDAO;
import entity.Student;
import java.io.File;
import java.io.IOException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.Part;


@MultipartConfig(fileSizeThreshold = 1024 * 1024 * 2, // 2MB
        maxFileSize = 1024 * 1024 * 10, // 10MB
        maxRequestSize = 1024 * 1024 * 50)   // 50MB
public class AddStudentServlet extends HttpServlet {

    /**
     * Name of the directory where uploaded files will be saved, relative to the
     * web application directory.
     */
    private static final String SAVE_DIR = "images";

    private DatabaseDAO dao;

    @Override
    public void init() throws ServletException {
        dao = new DatabaseDAO();
    }

    /**
     * Processes requests for both HTTP <code>GET</code> and <code>POST</code>
     * methods.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        // gets absolute path of the web application
        String appPath = request.getServletContext().getRealPath("");

        // constructs path of the directory to save uploaded file
        String savePath = appPath + SAVE_DIR;

        // creates the save directory if it does not exists
        File fileSaveDir = new File(savePath);
        if (!fileSaveDir.exists()) {
            fileSaveDir.mkdir();
        }

        String name = request.getParameter("name");
        String surname = request.getParameter("surname");
        String fileName;

        for (Part part : request.getParts()) {
            String contentDisp = part.getHeader("content-disposition");
            String[] items = contentDisp.split(";");
            for (String item : items) {
                String ss = item.trim();
                if (ss.startsWith("filename")) {
                    try {
                        int id = dao.insertStudentIntoDB(name, surname);
                        fileName = String.valueOf(id);
                        part.write(savePath + File.separator + fileName);
                        request.setAttribute("message", "Студент добавлен.");
                    } catch (IOException e) {
                        request.setAttribute("message", "Ошибка при добавлении студента!");
                    }
                }
            }
        }

        List<Student> students = dao.readAllStudentsFromDB();
        request.setAttribute("students", students);
        request.getRequestDispatcher("ShowAllStudent.jsp").forward(request, response);
    }

    private String extractName(String s) {
        return s.substring(s.indexOf("=") + 2, s.length() - 1);
    }

    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /**
     * Handles the HTTP <code>GET</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Handles the HTTP <code>POST</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }
}

package servlet;

import dao.DatabaseDAO;
import entity.Student;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

import static java.lang.Integer.parseInt;

import java.util.List;

public class MyServlet extends HttpServlet {

    private DatabaseDAO dao;

    @Override
    public void init() throws ServletException {
        dao = new DatabaseDAO();
    }

    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        String action = request.getParameter("actionname");

        if (action.equals("RemoveStudent")) {
            int id = parseInt(request.getParameter("id"));
            boolean deleted = dao.deleteStudentFromDB(id);

            String message;
            if (deleted) {
                message = "Студент удален.";
            } else {
                message = "Студент не существует";
            }
            request.setAttribute("message", message);

            List<Student> students = dao.readAllStudentsFromDB();
            request.setAttribute("students", students);

            request.getRequestDispatcher("ShowAllStudent.jsp").forward(request, response);
        }

        if (action.equals("ShowAllStudent")) {
            List<Student> students = dao.readAllStudentsFromDB();
            request.setAttribute("students", students);
            request.getRequestDispatcher("ShowAllStudent.jsp").forward(request, response);
        }
    }

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        processRequest(request, response);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        processRequest(request, response);
    }
}

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package servlet;

import dao.DatabaseDAO;
import entity.Student;
import java.io.File;
import java.io.IOException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.Part;


@MultipartConfig(fileSizeThreshold = 1024 * 1024 * 2, // 2MB
        maxFileSize = 1024 * 1024 * 10, // 10MB
        maxRequestSize = 1024 * 1024 * 50)   // 50MB
public class AddStudentServlet extends HttpServlet {

    /**
     * Name of the directory where uploaded files will be saved, relative to the
     * web application directory.
     */
    private static final String SAVE_DIR = "images";

    private DatabaseDAO dao;

    @Override
    public void init() throws ServletException {
        dao = new DatabaseDAO();
    }

    /**
     * Processes requests for both HTTP <code>GET</code> and <code>POST</code>
     * methods.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        // gets absolute path of the web application
        String appPath = request.getServletContext().getRealPath("");

        // constructs path of the directory to save uploaded file
        
        
         String savePath = "C:/Pictures";
         File fileSaveDir = new File(savePath); {
                
            }
         if (!fileSaveDir.exists()) { fileSaveDir.mkdirs(); }

        // creates the save directory if it does not exists
        

        String name = request.getParameter("name");
        String surname = request.getParameter("surname");
        String fileName;

        for (Part part : request.getParts()) {
            String contentDisp = part.getHeader("content-disposition");
            String[] items = contentDisp.split(";");
            for (String item : items) {
                String ss = item.trim();
                if (ss.startsWith("filename")) {
                    try {
                        int id = dao.insertStudentIntoDB(name, surname);
                        fileName = String.valueOf(id);
                        part.write(savePath + File.separator + fileName);
                        request.setAttribute("message", "Студент добавлен.");
                    } catch (IOException e) {
                        request.setAttribute("message", "Ошибка при добавлении студента!");
                    }
                }
            }
        }

        List<Student> students = dao.readAllStudentsFromDB();
        request.setAttribute("students", students);
        request.getRequestDispatcher("ShowAllStudent.jsp").forward(request, response);
    }

    private String extractName(String s) {
        return s.substring(s.indexOf("=") + 2, s.length() - 1);
    }

    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /**
     * Handles the HTTP <code>GET</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Handles the HTTP <code>POST</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }
}

package dao;

import entity.Student;

import java.sql.*;
import java.time.LocalDate;
import java.util.ArrayList;

public class DatabaseDAO {

    private static final String URL = "jdbc:mysql://localhost:3306/school_db_newnew?useTimezone=true&serverTimezone=GMT";
    private static final String USER = "root";
    private static final String PASSWORD = "123456";

    private static final String GET_ALL_STUDENTS_QUERY
            = "SELECT * FROM student;";

    private static final String INSERT_STUDENT_QUERY
            = "INSERT INTO student (name, surname) VALUES(?,?);";

    public static final String DELETE_STUDENT_QUERY = "DELETE FROM student WHERE id = ?;";

    private Connection conn;

    public DatabaseDAO() {
        try {
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection(URL, USER, PASSWORD);
        } catch (SQLException | ClassNotFoundException e) {
            throw new RuntimeException(e);
        }
    }

    public ArrayList<Student> readAllStudentsFromDB() {
        ArrayList<Student> result = new ArrayList<>();

        try (PreparedStatement stmt = conn.prepareStatement(GET_ALL_STUDENTS_QUERY)) {
            ResultSet rs = stmt.executeQuery();
            while (rs.next()) {
                int id = rs.getInt("id");
                String firstName = rs.getString("name");
                String lastName = rs.getString("surname");
                String patron = rs.getString("patron");
                Date date = rs.getDate("birthday");
                LocalDate birthday = null;
                if (date != null) {
                    birthday = date.toLocalDate();
                }
                String image = rs.getString("image");
                Student student = new Student(firstName, lastName, patron, birthday);
                student.setId(id);
                student.setImage(image);
                result.add(student);
            }
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }

        return result;
    }

    public int insertStudentIntoDB(String name, String surname) {
        try (PreparedStatement stmt
                = conn.prepareStatement(INSERT_STUDENT_QUERY, Statement.RETURN_GENERATED_KEYS)) {

            stmt.setString(1, name);
            stmt.setString(2, surname);

            stmt.executeUpdate();
            ResultSet keys = stmt.getGeneratedKeys();
            if (keys.next()) {
                return keys.getInt(1);
            }
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
        return -1;
    }

    public boolean deleteStudentFromDB(int id) {
        try (PreparedStatement stmt = conn.prepareStatement(DELETE_STUDENT_QUERY)) {
            stmt.setInt(1, id);
            int rowsDeleted = stmt.executeUpdate();
            return rowsDeleted > 0;
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }
}

package entity;

import java.time.LocalDate;
import java.util.ArrayList;

public class Student {

    private int id;
    private String name, surname, patron;
    private LocalDate birthDate;
    private String image;
    private ArrayList<Grade> grades;

    public Student(String name, String surname, String patron, LocalDate birthDate) {
        this.name = name;
        this.surname = surname;
        this.patron = patron;
        this.birthDate = birthDate;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public String getSurname() {
        return surname;
    }

    public String getPatron() {
        return patron;
    }

    public String getImage() {
        return image;
    }

    public void setImage(String image) {
        this.image = image;
    }

    public String getShortName() {
        return surname + " " + name.charAt(0) + "." + (patron == null ? "" : " " + patron.charAt(0) + ".");
    }

    public LocalDate getBirthDate() {
        return birthDate;
    }

    @Override
    public String toString() {
        return getShortName();
    }
}

      <div class="addstudent">
                <h1>Add Student</h1>
                <form action="AddStudent" method="Post" enctype="multipart/form-data">
                    name : <input type="text" name="name"><br><br>
                    surname : <input type="text" name="surname"><br><br>
                    image: <input name="data" type="file" accept="image/*"><br>
                    <input type="submit" value="Send"><br>
                </form>
            </div>
        </div>
    </body>
</html>