Java图书借阅系统实现教程

public class Book {
    private String title;
    private String author;
    private String isbn;
    private boolean isBorrowed;
public Book(String title, String author, String isbn) {
    this.title = title;
    this.author = author;
    this.isbn = isbn;
    this.isBorrowed = false;
}

// Getters
public String getTitle() { return title; }
public String getAuthor() { return author; }
public String getIsbn() { return isbn; }
public boolean isBorrowed() { return isBorrowed; }

// 借出图书
public void borrow() {
    if (!isBorrowed) {
        isBorrowed = true;
    } else {
        System.out.println("该书已被借出！");
    }
}

// 归还图书
public void returnBook() {
    isBorrowed = false;
}

@Override
public String toString() {
    return "《" + title + "》 by " + author + " (ISBN: " + isbn + ") - " +
           (isBorrowed ? "已借出" : "可借阅");
}
}

import java.util.ArrayList;
import java.util.List;
public class User {
private String name;
private List borrowedBooks;
public User(String name) {
    this.name = name;
    this.borrowedBooks = new ArrayList<>();
}

public String getName() { return name; }

public void borrowBook(Book book) {
    if (book != null && !book.isBorrowed()) {
        book.borrow();
        borrowedBooks.add(book);
        System.out.println(name + " 成功借阅: " + book.getTitle());
    } else {
        System.out.println("无法借阅此书！");
    }
}

public void returnBook(Book book) {
    if (borrowedBooks.remove(book)) {
        book.returnBook();
        System.out.println(name + " 已归还: " + book.getTitle());
    } else {
        System.out.println("你没有借这本书！");
    }
}

public List getBorrowedBooks() {
    return new ArrayList<>(borrowedBooks);
}
}

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
public class Library {
private List books;
private List users;
private Scanner scanner;
public Library() {
    books = new ArrayList<>();
    users = new ArrayList<>();
    scanner = new Scanner(System.in);
    initializeData(); // 初始化一些测试数据
}

// 初始化测试数据
private void initializeData() {
    books.add(new Book("Java编程思想", "Bruce Eckel", "978-7-121-02345-6"));
    books.add(new Book("Effective Java", "Joshua Bloch", "978-7-111-21382-6"));
    books.add(new Book("深入理解Java虚拟机", "周志明", "978-7-111-42157-5"));

    users.add(new User("张三"));
    users.add(new User("李四"));
}

// 添加新书
public void addBook(String title, String author, String isbn) {
    books.add(new Book(title, author, isbn));
    System.out.println("图书添加成功：" + title);
}

// 查找图书（按标题或作者）
public List searchBooks(String keyword) {
    List result = new ArrayList<>();
    for (Book book : books) {
        if (book.getTitle().contains(keyword) || book.getAuthor().contains(keyword)) {
            result.add(book);
        }
    }
    return result;
}

// 显示所有图书
public void displayAllBooks() {
    System.out.println("\n=== 所有图书 ===");
    for (Book book : books) {
        System.out.println(book);
    }
}

// 主菜单
public void start() {
    while (true) {
        System.out.println("\n--- 图书借阅管理系统 ---");
        System.out.println("1. 查看所有图书");
        System.out.println("2. 搜索图书");
        System.out.println("3. 借阅图书");
        System.out.println("4. 归还图书");
        System.out.println("5. 退出");
        System.out.print("请选择操作：");

        int choice = scanner.nextInt();
        scanner.nextLine(); // 消费换行符

        switch (choice) {
            case 1:
                displayAllBooks();
                break;
            case 2:
                searchBook();
                break;
            case 3:
                borrowBook();
                break;
            case 4:
                returnBook();
                break;
            case 5:
                System.out.println("感谢使用！");
                return;
            default:
                System.out.println("无效选择，请重试。");
        }
    }
}

private void searchBook() {
    System.out.print("请输入书名或作者关键词：");
    String keyword = scanner.nextLine();
    List results = searchBooks(keyword);
    if (results.isEmpty()) {
        System.out.println("未找到相关图书。");
    } else {
        System.out.println("搜索结果：");
        for (Book book : results) {
            System.out.println(book);
        }
    }
}

private void borrowBook() {
    System.out.print("输入用户名（张三/李四）：");
    String userName = scanner.nextLine();
    User user = users.stream()
            .filter(u -> u.getName().equals(userName))
            .findFirst()
            .orElse(null);

    if (user == null) {
        System.out.println("用户不存在！");
        return;
    }

    System.out.print("输入要借阅的书名：");
    String title = scanner.nextLine();
    Book book = books.stream()
            .filter(b -> b.getTitle().equals(title) && !b.isBorrowed())
            .findFirst()
            .orElse(null);

    if (book == null) {
        System.out.println("图书不可借阅（可能不存在或已被借出）");
    } else {
        user.borrowBook(book);
    }
}

private void returnBook() {
    System.out.print("输入用户名：");
    String userName = scanner.nextLine();
    User user = users.stream()
            .filter(u -> u.getName().equals(userName))
            .findFirst()
            .orElse(null);

    if (user == null) {
        System.out.println("用户不存在！");
        return;
    }

    List borrowed = user.getBorrowedBooks();
    if (borrowed.isEmpty()) {
        System.out.println("你没有借任何书。");
        return;
    }

    System.out.println("你借的书：");
    for (int i = 0; i < borrowed.size(); i++) {
        System.out.println((i + 1) + ". " + borrowed.get(i).getTitle());
    }

    System.out.print("选择要归还的书编号：");
    int index = scanner.nextInt() - 1;
    if (index >= 0 && index < borrowed.size()) {
        user.returnBook(borrowed.get(index));
    } else {
        System.out.println("无效编号！");
    }
}

public static void main(String[] args) {
    Library library = new Library();
    library.start();
}
}