题目二：模拟书店售书系统 功能需求如下： （1）书籍信息包括：编号、ISBN号、书名、作者、出版社、单价、库存数量。 销售信息包括：日期、ISBN号、数量、单价、总价。 （2）系统功能要求： 1）包括顾客和店员两个用户，顾客只可查询、购买书籍，店员可增、删、改、查、浏览及统计书籍销售情况； 2）书籍信息的增、删、改、查、浏览功能； 3）查询书籍：可ISBN号、书名、作者查询； 4）统计销售情况：输入日期，统计销售金额；输入ISBN号，统计销售金额。 5）书籍销售功能：输入ISBN号，购买数量，显示系统日期、ISBN号、数量、单价、总价，并写入文件。同步更新该书籍的库存数量。 （3）数据组织及存储要求 1）书籍信息、销售信息分别存储在2个文件（.txt）中，增、删、改、查、浏览等操作都是对文件操作，读写文件用多线程实现； 2）书籍、销售的信息在内存中要求使用泛型集合方式组织，具体实现类型自定。 （4）测试数据要求：存储书籍信息及销售信息的两个文件，至少各有10条数据。 （5）难度系数3，使用数据库、算法、前端等知识，可额外加分。 java代码实现

好的，以下是基于您提供的需求，使用 Java 实现的书店售书系统的代码：

Book.java

public class Book {
    private int id;
    private String isbn;
    private String name;
    private String author;
    private String publisher;
    private double price;
    private int stock;

    public Book(int id, String isbn, String name, String author, String publisher, double price, int stock) {
        this.id = id;
        this.isbn = isbn;
        this.name = name;
        this.author = author;
        this.publisher = publisher;
        this.price = price;
        this.stock = stock;
    }

    public int getId() {
        return id;
    }

    public String getIsbn() {
        return isbn;
    }

    public String getName() {
        return name;
    }

    public String getAuthor() {
        return author;
    }

    public String getPublisher() {
        return publisher;
    }

    public double getPrice() {
        return price;
    }

    public int getStock() {
        return stock;
    }

    public void setStock(int stock) {
        this.stock = stock;
    }
}

Sale.java

import java.text.SimpleDateFormat;
import java.util.Date;

public class Sale {
    private Date date;
    private String isbn;
    private int quantity;
    private double price;
    private double total;

    public Sale(String isbn, int quantity, double price) {
        this.date = new Date();
        this.isbn = isbn;
        this.quantity = quantity;
        this.price = price;
        this.total = quantity * price;
    }

    public String getDate() {
        SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
        return formatter.format(date);
    }

    public String getIsbn() {
        return isbn;
    }

    public int getQuantity() {
        return quantity;
    }

    public double getPrice() {
        return price;
    }

    public double getTotal() {
        return total;
    }

    public String toString() {
        return getDate() + "\t" + isbn + "\t" + quantity + "\t" + price + "\t" + total;
    }
}

BookStore.java

import java.io.*;
import java.util.*;

public class BookStore {
    private List<Book> books;
    private List<Sale> sales;
    private String bookFile;
    private String saleFile;

    public BookStore(String bookFile, String saleFile) {
        this.books = new ArrayList<>();
        this.sales = new ArrayList<>();
        this.bookFile = bookFile;
        this.saleFile = saleFile;
        loadBooks();
        loadSales();
    }

    public void customerMenu() {
        Scanner scanner = new Scanner(System.in);
        while (true) {
            System.out.println("欢迎来到图书店，您是顾客，您可以：");
            System.out.println("1. 查询书籍");
            System.out.println("2. 购买书籍");
            System.out.println("3. 退出");
            System.out.print("请输入您的选择：");
            int choice = scanner.nextInt();
            switch (choice) {
                case 1:
                    searchBooks();
                    break;
                case 2:
                    buyBook();
                    break;
                case 3:
                    System.out.println("感谢您的光临，再见！");
                    return;
                default:
                    System.out.println("无效的选择，请重新输入！");
            }
        }
    }

    public void staffMenu() {
        Scanner scanner = new Scanner(System.in);
        while (true) {
            System.out.println("欢迎来到图书店，您是店员，您可以：");
            System.out.println("1. 添加书籍");
            System.out.println("2. 删除书籍");
            System.out.println("3. 修改书籍信息");
            System.out.println("4. 查询书籍");
            System.out.println("5. 浏览书籍");
            System.out.println("6. 统计销售情况");
            System.out.println("7. 退出");
            System.out.print("请输入您的选择：");
            int choice = scanner.nextInt();
            switch (choice) {
                case 1:
                    addBook();
                    break;
                case 2:
                    deleteBook();
                    break;
                case 3:
                    modifyBook();
                    break;
                case 4:
                    searchBooks();
                    break;
                case 5:
                    browseBooks();
                    break;
                case 6:
                    statistics();
                    break;
                case 7:
                    System.out.println("感谢您的光临，再见！");
                    return;
                default:
                    System.out.println("无效的选择，请重新输入！");
            }
        }
    }

    public void addBook() {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入书籍信息：");
        System.out.print("编号：");
        int id = scanner.nextInt();
        System.out.print("ISBN号：");
        String isbn = scanner.next();
        System.out.print("书名：");
        String name = scanner.next();
        System.out.print("作者：");
        String author = scanner.next();
        System.out.print("出版社：");
        String publisher = scanner.next();
        System.out.print("单价：");
        double price = scanner.nextDouble();
        System.out.print("库存数量：");
        int stock = scanner.nextInt();
        Book book = new Book(id, isbn, name, author, publisher, price, stock);
        books.add(book);
        saveBooks();
        System.out.println("书籍已添加！");
    }

    public void deleteBook() {
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入要删除的书籍编号：");
        int id = scanner.nextInt();
        Book book = findBookById(id);
        if (book == null) {
            System.out.println("未找到编号为 " + id + " 的书籍！");
        } else {
            books.remove(book);
            saveBooks();
            System.out.println("书籍已删除！");
        }
    }

    public void modifyBook() {
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入要修改的书籍编号：");
        int id = scanner.nextInt();
        Book book = findBookById(id);
        if (book == null) {
            System.out.println("未找到编号为 " + id + " 的书籍！");
        } else {
            System.out.println("请输入要修改的书籍信息：");
            System.out.print("ISBN号（原值为 " + book.getIsbn() + "）：");
            String isbn = scanner.next();
            System.out.print("书名（原值为 " + book.getName() + "）：");
            String name = scanner.next();
            System.out.print("作者（原值为 " + book.getAuthor() + "）：");
            String author = scanner.next();
            System.out.print("出版社（原值为 " + book.getPublisher() + "）：");
            String publisher = scanner.next();
            System.out.print("单价（原值为 " + book.getPrice() + "）：");
            double price = scanner.nextDouble();
            System.out.print("库存数量（原值为 " + book.getStock() + "）：");
            int stock = scanner.nextInt();
            book.setIsbn(isbn);
            book.setName(name);
            book.setAuthor(author);
            book.setPublisher(publisher);
            book.setPrice(price);
            book.setStock(stock);
            saveBooks();
            System.out.println("书籍已修改！");
        }
    }

    public void searchBooks() {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入查询条件：");
        System.out.print("1. ISBN号；2. 书名；3. 作者：");
        int choice = scanner.nextInt();
        switch (choice) {
            case 1:
                System.out.print("请输入ISBN号：");
                String isbn = scanner.next();
                Book book = findBookByIsbn(isbn);
                if (book == null) {
                    System.out.println("未找到ISBN号为 " + isbn + " 的书籍！");
                } else {
                    System.out.println("查询结果：");
                    System.out.println("编号\tISBN号\t书名\t作者\t出版社\t单价\t库存数量");
                    System.out.println(book.getId() + "\t" + book.getIsbn() + "\t" + book.getName() + "\t" +
                            book.getAuthor() + "\t" + book.getPublisher() + "\t" + book.getPrice() + "\t" +
                            book.getStock());
                }
                break;
            case 2:
                System.out.print("请输入书名：");
                String name = scanner.next();
                List<Book> bookList = findBooksByName(name);
                if (bookList.isEmpty()) {
                    System.out.println("未找到书名为 " + name + " 的书籍！");
                } else {
                    System.out.println("查询结果：");
                    System.out.println("编号\tISBN号\t书名\t作者\t出版社\t单价\t库存数量");
                    for (Book b : bookList) {
                        System.out.println(b.getId() + "\t" + b.getIsbn() + "\t" + b.getName() + "\t" +
                                b.getAuthor() + "\t" + b.getPublisher() + "\t" + b.getPrice() + "\t" +
                                b.getStock());
                    }
                }
                break;
            case 3:
                System.out.print("请输入作者：");
                String author = scanner.next();
                bookList = findBooksByAuthor(author);
                if (bookList.isEmpty()) {
                    System.out.println("未找到作者为 " + author + " 的书籍！");
                } else {
                    System.out.println("查询结果：");
                    System.out.println("编号\tISBN号\t书名\t作者\t出版社\t单价\t库存数量");
                    for (Book b : bookList) {
                        System.out.println(b.getId() + "\t" + b.getIsbn() + "\t" + b.getName() + "\t" +
                                b.getAuthor() + "\t" + b.getPublisher() + "\t" + b.getPrice() + "\t" +
                                b.getStock());
                    }
                }
                break;
            default:
                System.out.println("无效的选择，请重新输入！");
        }
    }

    public void browseBooks() {
        System.out.println("图书馆中共有以下书籍：");
        System.out.println("编号\tISBN号\t书名\t作者\t出版社\t单价\t库存数量");
        for (Book book : books) {
            System.out.println(book.getId() + "\t" + book.getIsbn() + "\t" + book.getName() + "\t" +
                    book.getAuthor() + "\t" + book.getPublisher() + "\t" + book.getPrice() + "\t" +
                    book.getStock());
        }
    }

    public void buyBook() {
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入要购买的书籍的ISBN号：");
        String isbn = scanner.next();
        Book book = findBookByIsbn(isbn);
        if (book == null) {
            System.out.println("未找到ISBN号为 " + isbn + " 的书籍！");
        } else {
            System.out.print("请输入购买数量：");
            int quantity = scanner.nextInt();
            if (quantity > book.getStock()) {
                System.out.println("库存不足！");
            } else {
                Sale sale = new Sale(isbn, quantity, book.getPrice());
                sales.add(sale);
                book.setStock(book.getStock() - quantity);
                saveSales();
                saveBooks();
                System.out.println("购买成功！");
                System.out.println("系统日期\tISBN号\t数量\t单价\t总价");
                System.out.println(sale.toString());
            }
        }
    }

    public void statistics() {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入统计条件：");
        System.out.print("1. 日期；2. ISBN号：");
        int choice = scanner.nextInt();
        switch (choice) {
            case 1:
                System.out.print("请输入日期（格式：yyyy-MM-dd）：");
                String dateStr = scanner.next();
                double total = 0;
                for (Sale sale : sales) {
                    if (sale.getDate().equals(dateStr)) {