MySQL と Java を使用してシンプルなオンライン ショッピング システムを開発する方法

CREATE TABLE product (
  id INT PRIMARY KEY AUTO_INCREMENT,
  name VARCHAR(100) NOT NULL,
  price DECIMAL(10, 2) NOT NULL,
  quantity INT NOT NULL
);

CREATE TABLE user (
  id INT PRIMARY KEY AUTO_INCREMENT,
  name VARCHAR(100) NOT NULL,
  email VARCHAR(100) NOT NULL,
  password VARCHAR(100) NOT NULL
);

CREATE TABLE order (
  id INT PRIMARY KEY AUTO_INCREMENT,
  user_id INT NOT NULL,
  product_id INT NOT NULL,
  quantity INT NOT NULL,
  total DECIMAL(10, 2) NOT NULL,
  FOREIGN KEY (user_id) REFERENCES user(id),
  FOREIGN KEY (product_id) REFERENCES product(id)
);

import java.sql.*;

public class DatabaseConnection {
  private static final String URL = "jdbc:mysql://localhost:3306/your_database_name";
  private static final String USERNAME = "your_username";
  private static final String PASSWORD = "your_password";

  public static Connection getConnection() {
    try {
      return DriverManager.getConnection(URL, USERNAME, PASSWORD);
    } catch (SQLException e) {
      e.printStackTrace();
      return null;
    }
  }
}

import java.sql.*;

public class ProductDao {
  public void addProduct(Product product) {
    try (Connection conn = DatabaseConnection.getConnection();
         PreparedStatement stmt = conn.prepareStatement("INSERT INTO product (name, price, quantity) VALUES (?, ?, ?)")) {
      stmt.setString(1, product.getName());
      stmt.setDouble(2, product.getPrice());
      stmt.setInt(3, product.getQuantity());
      
      stmt.executeUpdate();
    } catch (SQLException e) {
      e.printStackTrace();
    }
  }
  
  // 其他商品管理功能的代码...
}

import java.sql.*;

public class UserDao {
  public void addUser(User user) {
    try (Connection conn = DatabaseConnection.getConnection();
         PreparedStatement stmt = conn.prepareStatement("INSERT INTO user (name, email, password) VALUES (?, ?, ?)")) {
      stmt.setString(1, user.getName());
      stmt.setString(2, user.getEmail());
      stmt.setString(3, user.getPassword());
      
      stmt.executeUpdate();
    } catch (SQLException e) {
      e.printStackTrace();
    }
  }
  
  // 其他用户管理功能的代码...
}

import java.sql.*;

public class OrderDao {
  public void addOrder(Order order) {
    try (Connection conn = DatabaseConnection.getConnection();
         PreparedStatement stmt = conn.prepareStatement("INSERT INTO order (user_id, product_id, quantity, total) VALUES (?, ?, ?, ?)")) {
      stmt.setInt(1, order.getUserId());
      stmt.setInt(2, order.getProductId());
      stmt.setInt(3, order.getQuantity());
      stmt.setDouble(4, order.getTotal());
      
      stmt.executeUpdate();
    } catch (SQLException e) {
      e.printStackTrace();
    }
  }
  
  // 其他订单管理功能的代码...
}