编写一款图书管理系统的Java代码

好的，以下是一份简单的图书管理系统的Java代码：

import java.util.ArrayList;
import java.util.Scanner;

public class BookManagementSystem {
    private ArrayList<Book> bookList;

    public BookManagementSystem() {
        bookList = new ArrayList<Book>();
    }

    public void addBook(Book book) {
        bookList.add(book);
    }

    public void removeBook(Book book) {
        bookList.remove(book);
    }

    public void displayBooks() {
        if (bookList.size() == 0) {
            System.out.println("There are no books in the library.");
        } else {
            for (Book book : bookList) {
                System.out.println(book);
            }
        }
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        BookManagementSystem system = new BookManagementSystem();

        while (true) {
            System.out.println("1. Add book");
            System.out.println("2. Remove book");
            System.out.println("3. Display books");
            System.out.println("4. Exit");
            System.out.print("Enter your choice: ");
            int choice = scanner.nextInt();
            scanner.nextLine();

            switch (choice) {
                case 1:
                    System.out.print("Enter book title: ");
                    String title = scanner.nextLine();
                    System.out.print("Enter book author: ");
                    String author = scanner.nextLine();
                    System.out.print("Enter book ISBN: ");
                    String isbn = scanner.nextLine();
                    Book book = new Book(title, author, isbn);
                    system.addBook(book);
                    break;
                case 2:
                    System.out.print("Enter book title: ");
                    title = scanner.nextLine();
                    System.out.print("Enter book author: ");
                    author = scanner.nextLine();
                    System.out.print("Enter book ISBN: ");
                    isbn = scanner.nextLine();
                    book = new Book(title, author, isbn);
                    system.removeBook(book);
                    break;
                case 3:
                    system.displayBooks();
                    break;
                case 4:
                    System.exit(0);
                default:
                    System.out.println("Invalid choice. Please try again.");
            }
        }
    }
}

class Book {
    private String title;
    private String author;
    private String isbn;

    public Book(String title, String author, String isbn) {
        this.title = title;
        this.author = author;
        this.isbn = isbn;
    }

    public String getTitle() {
        return title;
    }

    public String getAuthor() {
        return author;
    }

    public String getIsbn() {
        return isbn;
    }

    @Override
    public String toString() {
        return "Title: " + title + ", Author: " + author + ", ISBN: " + isbn;
    }
}

这份代码实现了以下功能：

1. 添加图书
2. 删除图书
3. 显示所有图书
4. 退出程序

每本图书由书名、作者和ISBN号组成。用户可以根据自己的需求添加、删除和查看图书。