图书馆管理系统 Java代码

以下是一个简单的图书馆管理系统的 Java 代码示例：

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

public class LibrarySystem {
    private static ArrayList<Book> bookList = new ArrayList<>();

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int choice;
        do {
            System.out.println("1. Add Book");
            System.out.println("2. Display All Books");
            System.out.println("3. Search Book");
            System.out.println("4. Delete Book");
            System.out.println("5. Exit");
            System.out.print("Enter your choice: ");
            choice = scanner.nextInt();
            switch (choice) {
                case 1:
                    addBook();
                    break;
                case 2:
                    displayAllBooks();
                    break;
                case 3:
                    searchBook();
                    break;
                case 4:
                    deleteBook();
                    break;
                case 5:
                    System.out.println("Exiting Library System...");
                    break;
                default:
                    System.out.println("Invalid choice. Please try again.");
            }
        } while (choice != 5);
    }

    private static void addBook() {
        Scanner scanner = new Scanner(System.in);
        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();
        System.out.print("Enter book year: ");
        int year = scanner.nextInt();
        Book book = new Book(title, author, isbn, year);
        bookList.add(book);
        System.out.println("Book added successfully.");
    }

    private static void displayAllBooks() {
        if (bookList.size() == 0) {
            System.out.println("No books found.");
        } else {
            System.out.println("Books in the library:");
            for (Book book : bookList) {
                System.out.println(book);
            }
        }
    }

    private static void searchBook() {
        Scanner scanner = new Scanner(System.in);
        System.out.print("Enter book title or author: ");
        String query = scanner.nextLine();
        ArrayList<Book> results = new ArrayList<>();
        for (Book book : bookList) {
            if (book.getTitle().contains(query) || book.getAuthor().contains(query)) {
                results.add(book);
            }
        }
        if (results.size() == 0) {
            System.out.println("No results found.");
        } else {
            System.out.println("Results for \"" + query + "\":");
            for (Book book : results) {
                System.out.println(book);
            }
        }
    }

    private static void deleteBook() {
        Scanner scanner = new Scanner(System.in);
        System.out.print("Enter book title or author: ");
        String query = scanner.nextLine();
        ArrayList<Book> results = new ArrayList<>();
        for (Book book : bookList) {
            if (book.getTitle().contains(query) || book.getAuthor().contains(query)) {
                results.add(book);
            }
        }
        if (results.size() == 0) {
            System.out.println("No results found.");
        } else {
            System.out.println("Results for \"" + query + "\":");
            for (int i = 0; i < results.size(); i++) {
                Book book = results.get(i);
                System.out.println((i + 1) + ". " + book);
            }
            System.out.print("Enter the number of the book to delete: ");
            int index = scanner.nextInt() - 1;
            bookList.remove(results.get(index));
            System.out.println("Book deleted successfully.");
        }
    }
}

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

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

    public String getTitle() {
        return title;
    }

    public String getAuthor() {
        return author;
    }

    public String getIsbn() {
        return isbn;
    }

    public int getYear() {
        return year;
    }

    @Override
    public String toString() {
        return title + " by " + author + " (" + year + ")";
    }
}

这个简单的图书馆管理系统可以让用户添加、显示、搜索和删除图书。图书信息存储在一个 `ArrayList` 中，每本书由 `Book` 类表示。用户可以根据书名或作者搜索图书，并选择要删除的图书。