如何使用MySQL和Java实现一个在线图书借阅系统

CREATE TABLE Book (
    bookId INT AUTO_INCREMENT PRIMARY KEY,
    title VARCHAR(255),
    author VARCHAR(255),
    publisher VARCHAR(255)
);

CREATE TABLE User (
    userId INT AUTO_INCREMENT PRIMARY KEY,
    username VARCHAR(255),
    passWord VARCHAR(255)
);

CREATE TABLE Borrow (
    borrowId INT AUTO_INCREMENT PRIMARY KEY,
    bookId INT,
    userId INT,
    borrowDate DATE,
    returnDate DATE,
    FOREIGN KEY (bookId) REFERENCES Book(bookId),
    FOREIGN KEY (userId) REFERENCES User(userId)
);

public class BookDao {
    public void addBook(Book book) {
        // 连接数据库
        Connection connection = // 连接数据库代码

        // 执行插入操作
        String sql = "INSERT INTO Book (title, author, publisher) VALUES (?, ?, ?)";
        PreparedStatement statement = connection.prepareStatement(sql);
        statement.setString(1, book.getTitle());
        statement.setString(2, book.getAuthor());
        statement.setString(3, book.getPublisher());
        statement.executeUpdate();

        // 关闭连接
        connection.close();
    }
}

public class BorrowDao {
    public void borrowBook(int bookId, int userId) {
        // 连接数据库
        Connection connection = // 连接数据库代码

        // 执行插入操作
        String sql = "INSERT INTO Borrow (bookId, userId, borrowDate) VALUES (?, ?, ?)";
        PreparedStatement statement = connection.prepareStatement(sql);
        statement.setInt(1, bookId);
        statement.setInt(2, userId);
        statement.setDate(3, new Date(System.currentTimeMillis()));
        statement.executeUpdate();

        // 关闭连接
        connection.close();
    }
}

public class BorrowDao {
    public void returnBook(int borrowId) {
        // 连接数据库
        Connection connection = // 连接数据库代码

        // 执行更新操作
        String sql = "UPDATE Borrow SET returnDate = ? WHERE borrowId = ?";
        PreparedStatement statement = connection.prepareStatement(sql);
        statement.setDate(1, new Date(System.currentTimeMillis()));
        statement.setInt(2, borrowId);
        statement.executeUpdate();

        // 关闭连接
        connection.close();
    }
}