9. Список литературы

1. Бирюков, М.А. Лекции по дисциплине «Web-технологии». – СПб.: СПбГУТ, – [Электронный ресурс], [дата обращения – ноябрь 2025 г.].

2. Oracle Corporation. MySQL 8.0 Reference Manual. — [Электронный ресурс]. — Режим доступа: https://dev.mysql.com/doc/refman/8.0/en/, свободный. — [Дата обращения: ноябрь 2025 г.]

3. Курняван Б. Создание WEB-приложений на языке Java с помощью сервлетов, JSP и EJB [Электронный ресурс] — СПб.:Лори, 2005. — 857 с. – Режим доступа: https://clck.ru/3Qcow4 , [дата обращения – ноябрь 2025 г.]

4. JavaRush. Знакомство с DAO — [Электронный ресурс]. – Режим доступа: https://javarush.com/quests/lectures/questhibernate.level16.lecture04, [дата обращения – ноябрь 2025 г.].

5. JavaRush. Знакомство с паттерном MVC— [Электронный ресурс]. – Режим доступа: https://javarush.com/groups/posts/2536-chastjh-7-znakomstvo-s-patternom-mvc-model-view-controller, [дата обращения – ноябрь 2025 г.].

6. JavaRush. Сервлеты, Java servlet API. Пишем простое веб-приложение — [Электронный ресурс]. – Режим доступа: https://javarush.com/groups/posts/2529-chastjh-5-servletih-pishem-prostoe-veb-prilozhenie, [дата обращения – ноябрь 2025 г.].

7. JavaRush. Основы Maven — [Электронный ресурс]. – Режим доступа: https://javarush.com/groups/posts/2523-chastjh-4osnovih-maven, [дата обращения – ноябрь 2025 г.].

10. Приложение

10.1. Book.java

package com.ivanov.bookstore.model;

public class Book {

private int id;

private String title;

private String author;

private double price;

private String imageUrl;

private int quantity;

public Book() {}

public Book(String title, String author, double price, String imageUrl, int quantity) {

this.title = title;

this.author = author;

this.price = price;

this.imageUrl = imageUrl;

this.quantity = quantity;

}

// Геттеры и сеттеры

public int getId() { return id; }

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

public String getTitle() { return title; }

public void setTitle(String title) { this.title = title; }

public String getAuthor() { return author; }

public void setAuthor(String author) { this.author = author; }

public double getPrice() { return price; }

public void setPrice(double price) { this.price = price; }

public String getImageUrl() { return imageUrl; }

public void setImageUrl(String imageUrl) { this.imageUrl = imageUrl; }

public int getQuantity() { return quantity; }

public void setQuantity(int quantity) { this.quantity = quantity; }

}

10.2. CartItem.java

package com.ivanov.bookstore.model;

public class CartItem {

private int id;

private int userId;

private int bookId;

private int quantity;

private Book book;

public CartItem() {}

public CartItem(int userId, int bookId, int quantity) {

this.userId = userId;

this.bookId = bookId;

this.quantity = quantity;

}

public int getId() { return id; }

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

public int getUserId() { return userId; }

public void setUserId(int userId) { this.userId = userId; }

public int getBookId() { return bookId; }

public void setBookId(int bookId) { this.bookId = bookId; }

public int getQuantity() { return quantity; }

public void setQuantity(int quantity) { this.quantity = quantity; }

public Book getBook() { return book; }

public void setBook(Book book) { this.book = book; }

}

10.3. User.java

package com.ivanov.bookstore.model;

public class User {

private int id;

private String username;

private String password;

private String email;

public User() {}

public User(String username, String password, String email) {

this.username = username;

this.password = password;

this.email = email;

}

public int getId() { return id; }

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

public String getUsername() { return username; }

public void setUsername(String username) { this.username = username; }

public String getPassword() { return password; }

public void setPassword(String password) { this.password = password; }

public String getEmail() { return email; }

public void setEmail(String email) { this.email = email; }

}

10.4. BookDao.java

package com.ivanov.bookstore.dao;

import com.ivanov.bookstore.model.Book;

import java.sql.*;

import java.util.ArrayList;

import java.util.List;

public class BookDao {

public List<Book> getAllBooks() {

List<Book> books = new ArrayList<>();

String sql = "SELECT * FROM books";

try (Connection conn = DatabaseConnection.getConnection();

PreparedStatement stmt = conn.prepareStatement(sql);

ResultSet rs = stmt.executeQuery()) {

while (rs.next()) {

Book book = new Book();

book.setId(rs.getInt("id"));

book.setTitle(rs.getString("title"));

book.setAuthor(rs.getString("author"));

book.setPrice(rs.getDouble("price"));

book.setImageUrl(rs.getString("image_url"));

book.setQuantity(rs.getInt("quantity"));

books.add(book);

}

} catch (SQLException e) {

e.printStackTrace();

}

return books;

}

public boolean decreaseBookQuantity(int bookId, int quantity) {

String sql = "UPDATE books SET quantity = quantity - ? WHERE id = ? AND quantity >= ?";

try (Connection conn = DatabaseConnection.getConnection();

PreparedStatement stmt = conn.prepareStatement(sql)) {

stmt.setInt(1, quantity);

stmt.setInt(2, bookId);

stmt.setInt(3, quantity);

return stmt.executeUpdate() > 0;

} catch (SQLException e) {

e.printStackTrace();

return false;

}

}

}

10.5. CartDao.java

package com.ivanov.bookstore.dao;

import com.ivanov.bookstore.model.CartItem;

import com.ivanov.bookstore.model.Book;

import java.sql.*;

import java.util.ArrayList;

import java.util.List;

public class CartDao {

public List<CartItem> getCartItemsByUserId(int userId) {

List<CartItem> cartItems = new ArrayList<>();

String sql = "SELECT ci.*, b.title, b.author, b.price, b.image_url, b.quantity as book_quantity " +

"FROM cart_items ci " +

"JOIN books b ON ci.book_id = b.id " +

"WHERE ci.user_id = ?";

try (Connection conn = DatabaseConnection.getConnection();

PreparedStatement stmt = conn.prepareStatement(sql)) {

stmt.setInt(1, userId);

try (ResultSet rs = stmt.executeQuery()) {

while (rs.next()) {

CartItem item = new CartItem();

item.setId(rs.getInt("id"));

item.setUserId(rs.getInt("user_id"));

item.setBookId(rs.getInt("book_id"));

item.setQuantity(rs.getInt("quantity"));

Book book = new Book();

book.setId(rs.getInt("book_id"));

book.setTitle(rs.getString("title"));

book.setAuthor(rs.getString("author"));

book.setPrice(rs.getDouble("price"));

book.setImageUrl(rs.getString("image_url"));

book.setQuantity(rs.getInt("book_quantity"));

item.setBook(book);

cartItems.add(item);

}

}

} catch (SQLException e) {

e.printStackTrace();

}

return cartItems;

}

public boolean addToCart(int userId, int bookId) {

// Сначала проверяем, есть ли уже такая книга в корзине

CartItem existingItem = findCartItem(userId, bookId);

if (existingItem != null) {

// Если книга уже есть - увеличиваем количество

String updateSql = "UPDATE cart_items SET quantity = quantity + 1 WHERE id = ?";

try (Connection conn = DatabaseConnection.getConnection();

PreparedStatement stmt = conn.prepareStatement(updateSql)) {

stmt.setInt(1, existingItem.getId());

return stmt.executeUpdate() > 0;

} catch (SQLException e) {

e.printStackTrace();

return false;

}

} else {

// Если книги нет - добавляем новую запись

String insertSql = "INSERT INTO cart_items (user_id, book_id, quantity) VALUES (?, ?, 1)";

try (Connection conn = DatabaseConnection.getConnection();

PreparedStatement stmt = conn.prepareStatement(insertSql)) {

stmt.setInt(1, userId);

stmt.setInt(2, bookId);

return stmt.executeUpdate() > 0;

} catch (SQLException e) {

e.printStackTrace();

return false;

}

}

}

public boolean removeFromCart(int cartItemId) {

String sql = "DELETE FROM cart_items WHERE id = ?";

try (Connection conn = DatabaseConnection.getConnection();

PreparedStatement stmt = conn.prepareStatement(sql)) {

stmt.setInt(1, cartItemId);

return stmt.executeUpdate() > 0;

} catch (SQLException e) {

e.printStackTrace();

return false;

}

}

public void clearUserCart(int userId) {

String sql = "DELETE FROM cart_items WHERE user_id = ?";

try (Connection conn = DatabaseConnection.getConnection();

PreparedStatement stmt = conn.prepareStatement(sql)) {

stmt.setInt(1, userId);

stmt.executeUpdate();

} catch (SQLException e) {

e.printStackTrace();

}

}

public CartItem findCartItem(int userId, int bookId) {

String sql = "SELECT * FROM cart_items WHERE user_id = ? AND book_id = ?";

try (Connection conn = DatabaseConnection.getConnection();

PreparedStatement stmt = conn.prepareStatement(sql)) {

stmt.setInt(1, userId);

stmt.setInt(2, bookId);

try (ResultSet rs = stmt.executeQuery()) {

if (rs.next()) {

CartItem item = new CartItem();

item.setId(rs.getInt("id"));

item.setUserId(rs.getInt("user_id"));

item.setBookId(rs.getInt("book_id"));

item.setQuantity(rs.getInt("quantity"));

return item;

}

}

} catch (SQLException e) {

e.printStackTrace();

}

return null;

}

public boolean updateCartItemQuantity(int cartItemId, int quantity) {

String sql = "UPDATE cart_items SET quantity = ? WHERE id = ?";

try (Connection conn = DatabaseConnection.getConnection();

PreparedStatement stmt = conn.prepareStatement(sql)) {

stmt.setInt(1, quantity);

stmt.setInt(2, cartItemId);

return stmt.executeUpdate() > 0;

} catch (SQLException e) {

e.printStackTrace();

return false;

}

}

}

10.6. UserDao.java

package com.ivanov.bookstore.dao;

import com.ivanov.bookstore.model.User;

import java.sql.*;

public class UserDao {

public User findUserByUsername(String username) {

String sql = "SELECT * FROM users WHERE username = ?";

User user = null;

try (Connection conn = DatabaseConnection.getConnection();

PreparedStatement stmt = conn.prepareStatement(sql)) {

stmt.setString(1, username);

try (ResultSet rs = stmt.executeQuery()) {

if (rs.next()) {

user = new User();

user.setId(rs.getInt("id"));

user.setUsername(rs.getString("username"));

user.setPassword(rs.getString("password"));

user.setEmail(rs.getString("email"));

}

}

} catch (SQLException e) {

e.printStackTrace();

}

return user;

}

public boolean registerUser(User user) {

String sql = "INSERT INTO users (username, password, email) VALUES (?, ?, ?)";

System.out.println(" Attempting to register user: " + user.getUsername());

try (Connection conn = DatabaseConnection.getConnection();

PreparedStatement stmt = conn.prepareStatement(sql)) {

stmt.setString(1, user.getUsername());

stmt.setString(2, user.getPassword());

stmt.setString(3, user.getEmail());

boolean result = stmt.executeUpdate() > 0;

System.out.println(" Registration result: " + result);

return result;

} catch (SQLException e) {

System.out.println(" Database error: " + e.getMessage());

e.printStackTrace();

return false;

}

}

public boolean validatePassword(String plainPassword, String hashedPassword) {

return plainPassword.equals(hashedPassword);

}

}

10.7. DatabaseConnection.java

package com.ivanov.bookstore.dao;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.SQLException;

public class DatabaseConnection {

private static final String URL = "jdbc:mysql://localhost:3306/bookstore";

private static final String USER = "root";

private static final String PASSWORD = "??????";

public static Connection getConnection() throws SQLException {

try {

Class.forName("com.mysql.cj.jdbc.Driver");

} catch (ClassNotFoundException e) {

throw new SQLException("MySQL Driver not found", e);

}

return DriverManager.getConnection(URL, USER, PASSWORD);

}

}

10.8. AuthServlet.java

package com.ivanov.bookstore.servlets;

import com.ivanov.bookstore.dao.UserDao;

import com.ivanov.bookstore.model.User;

import javax.servlet.*;

import javax.servlet.http.*;

import javax.servlet.annotation.*;

import java.io.IOException;

@WebServlet("/auth/*")

public class AuthServlet extends HttpServlet {

private UserDao userDao = new UserDao();

@Override

protected void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType("application/json");

response.setCharacterEncoding("UTF-8");

String pathInfo = request.getPathInfo();

if ("/login".equals(pathInfo)) {

handleLogin(request, response);

} else if ("/register".equals(pathInfo)) {

handleRegister(request, response);

} else if ("/logout".equals(pathInfo)) {

handleLogout(request, response);

}

}

private void handleLogin(HttpServletRequest request, HttpServletResponse response) throws IOException {

String username = request.getParameter("username");

String password = request.getParameter("password");

User user = userDao.findUserByUsername(username);

if (user != null && userDao.validatePassword(password, user.getPassword())) {

HttpSession session = request.getSession();

session.setAttribute("user", user);

session.setAttribute("userId", user.getId());

response.getWriter().write("{\"success\": true, \"message\": \"Login successful\"}");

} else {

response.getWriter().write("{\"success\": false, \"message\": \"Invalid username or password\"}");

}

}

private void handleRegister(HttpServletRequest request, HttpServletResponse response) throws IOException {

String username = request.getParameter("username");

String password = request.getParameter("password");

String email = request.getParameter("email");

// Проверяем, не существует ли уже пользователь

if (userDao.findUserByUsername(username) != null) {

response.getWriter().write("{\"success\": false, \"message\": \"Username already exists\"}");

return;

}

User newUser = new User(username, password, email);

if (userDao.registerUser(newUser)) {

response.getWriter().write("{\"success\": true, \"message\": \"Registration successful\"}");

} else {

response.getWriter().write("{\"success\": false, \"message\": \"Registration failed\"}");

}

}

private void handleLogout(HttpServletRequest request, HttpServletResponse response) throws IOException {

request.getSession().invalidate();

response.getWriter().write("{\"success\": true, \"message\": \"Logout successful\"}");

}

}

10.9. BookServlet.java

package com.ivanov.bookstore.servlets;

import com.ivanov.bookstore.dao.BookDao;

import com.ivanov.bookstore.model.Book;

import javax.servlet.*;

import javax.servlet.http.*;

import javax.servlet.annotation.*;

import java.io.IOException;

import java.util.List;

@WebServlet("/books")

public class BookServlet extends HttpServlet {

private BookDao bookDao = new BookDao();

@Override

protected void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType("application/json");

response.setCharacterEncoding("UTF-8");

List<Book> books = bookDao.getAllBooks();

StringBuilder json = new StringBuilder("[");

for (Book book : books) {

json.append("{")

.append("\"id\":").append(book.getId()).append(",")

.append("\"title\":\"").append(escapeJson(book.getTitle())).append("\",")

.append("\"author\":\"").append(escapeJson(book.getAuthor())).append("\",")

.append("\"price\":").append(book.getPrice()).append(",")

.append("\"imageUrl\":\"").append(escapeJson(book.getImageUrl())).append("\",")

.append("\"quantity\":").append(book.getQuantity())

.append("},");

}

if (books.size() > 0) {

json.deleteCharAt(json.length() - 1);

}

json.append("]");

response.getWriter().write(json.toString());

}

private String escapeJson(String str) {

if (str == null) return "";

return str.replace("\"", "\\\"")

.replace("\n", "\\n")

.replace("\r", "\\r")

.replace("\t", "\\t");

}

}

10.10. CartServlet.java

package com.ivanov.bookstore.servlets;

import com.ivanov.bookstore.dao.CartDao;

import com.ivanov.bookstore.model.CartItem;

import javax.servlet.*;

import javax.servlet.http.*;

import javax.servlet.annotation.*;

import java.io.IOException;

import java.util.List;

import com.ivanov.bookstore.dao.BookDao;

@WebServlet("/cart/*")

public class CartServlet extends HttpServlet {

private CartDao cartDao = new CartDao();

@Override

protected void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType("application/json");

response.setCharacterEncoding("UTF-8");

HttpSession session = request.getSession();

Integer userId = (Integer) session.getAttribute("userId");

if (userId == null) {

response.getWriter().write("{\"error\": \"Not logged in\"}");

return;

}

List<CartItem> cartItems = cartDao.getCartItemsByUserId(userId);

StringBuilder json = new StringBuilder("[");

for (CartItem item : cartItems) {

json.append("{")

.append("\"id\":").append(item.getId()).append(",")

.append("\"bookId\":").append(item.getBookId()).append(",")

.append("\"quantity\":").append(item.getQuantity()).append(",")

.append("\"title\":\"").append(escapeJson(item.getBook().getTitle())).append("\",")

.append("\"author\":\"").append(escapeJson(item.getBook().getAuthor())).append("\",")

.append("\"price\":").append(item.getBook().getPrice()).append(",")

.append("\"imageUrl\":\"").append(escapeJson(item.getBook().getImageUrl())).append("\",")

.append("\"bookQuantity\":").append(item.getBook().getQuantity())

.append("},");

}

if (cartItems.size() > 0) {

json.deleteCharAt(json.length() - 1);

}

json.append("]");

response.getWriter().write(json.toString());

}

@Override

protected void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType("application/json");

response.setCharacterEncoding("UTF-8");

HttpSession session = request.getSession();

Integer userId = (Integer) session.getAttribute("userId");

String pathInfo = request.getPathInfo();

if (userId == null) {

response.getWriter().write("{\"success\": false, \"message\": \"Not logged in\"}");

return;

}

if ("/add".equals(pathInfo)) {

int bookId = Integer.parseInt(request.getParameter("bookId"));

boolean success = cartDao.addToCart(userId, bookId);

response.getWriter().write("{\"success\": " + success + "}");

} else if ("/remove".equals(pathInfo)) {

int cartItemId = Integer.parseInt(request.getParameter("cartItemId"));

boolean success = cartDao.removeFromCart(cartItemId);

response.getWriter().write("{\"success\": " + success + "}");

} else if ("/update".equals(pathInfo)) {

int cartItemId = Integer.parseInt(request.getParameter("cartItemId"));

int quantity = Integer.parseInt(request.getParameter("quantity"));

boolean success = cartDao.updateCartItemQuantity(cartItemId, quantity);

response.getWriter().write("{\"success\": " + success + "}");

} else if ("/purchase".equals(pathInfo)) {

handlePurchase(userId, response);

}

}

private void handlePurchase(int userId, HttpServletResponse response) throws IOException {

BookDao bookDao = new BookDao();

List<CartItem> cartItems = cartDao.getCartItemsByUserId(userId);

// Проверяем достаточно ли книг на складе

for (CartItem item : cartItems) {

if (item.getQuantity() > item.getBook().getQuantity()) {

response.getWriter().write("{\"success\": false, \"message\": \"Недостаточно книг: \" + item.getBook().getTitle() + \" (доступно: \" + item.getBook().getQuantity() + \")\"}");

return;

}

}

// Уменьшаем количество книг

boolean allUpdated = true;

for (CartItem item : cartItems) {

boolean updated = bookDao.decreaseBookQuantity(item.getBookId(), item.getQuantity());

if (!updated) {

allUpdated = false;

break;

}

}

if (allUpdated) {

// Очищаем корзину только если все обновления прошли успешно

cartDao.clearUserCart(userId);

response.getWriter().write("{\"success\": true, \"message\": \"Покупка завершена успешно!\"}");

} else {

response.getWriter().write("{\"success\": false, \"message\": \"Ошибка при обновлении количества книг\"}");

}

}

private String escapeJson(String str) {

if (str == null) return "";

return str.replace("\"", "\\\"")

.replace("\n", "\\n")

.replace("\r", "\\r")

.replace("\t", "\\t");

}

}

10.11. pom.xml

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="http://maven.apache.org/POM/4.0.0

http://maven.apache.org/xsd/maven-4.0.0.xsd">

<modelVersion>4.0.0</modelVersion>

<groupId>com.ivanov</groupId>

<artifactId>bookstore</artifactId>

<version>1.0-SNAPSHOT</version>

<packaging>war</packaging>

<properties>

<maven.compiler.source>1.8</maven.compiler.source>

<maven.compiler.target>1.8</maven.compiler.target>

<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>

</properties>

<dependencies>

<dependency>

<groupId>javax.servlet</groupId>

<artifactId>javax.servlet-api</artifactId>

<version>4.0.1</version>

</dependency>

<dependency>

<groupId>com.mysql</groupId>

<artifactId>mysql-connector-j</artifactId>

<version>8.0.33</version>

</dependency>

</dependencies>

<build>

<finalName>bookstore</finalName>

<plugins>

<plugin>

<groupId>org.apache.maven.plugins</groupId>

<artifactId>maven-compiler-plugin</artifactId>

<version>3.11.0</version>

<configuration>

<source>1.8</source>

<target>1.8</target>

<forceJavacCompilerUse>true</forceJavacCompilerUse>

</configuration>

</plugin>

<plugin>

<groupId>org.eclipse.jetty</groupId>

<artifactId>jetty-maven-plugin</artifactId>

<version>9.4.51.v20230217</version>

<configuration>

<httpConnector>

<port>8081</port>

</httpConnector>

</configuration>

</plugin>

</plugins>

</build>

</project>