用java写一个基于控制台的购书系统

创建一个基于控制台的购书系统需要考虑几个基本要素，包括图书信息的存储、用户界面以及购物流程。下面是一个简单的Java购书系统实现的示例：

import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

public class BookStore {
    private Map<String, Book> bookCatalog = new HashMap<>();
    private Map<String, Integer> shoppingCart = new HashMap<>();
    private Scanner scanner = new Scanner(System.in);

    public static void main(String[] args) {
        BookStore store = new BookStore();
        store.loadBooks();
        store.run();
    }

    private void loadBooks() {
        // 这里可以添加代码，从文件读取或者数据库加载图书信息到bookCatalog
    }

    private void run() {
        boolean exit = false;
        while (!exit) {
            System.out.println("欢迎来到购书系统");
            System.out.println("1. 查看图书");
            System.out.println("2. 购买图书");
            System.out.println("3. 结算");
            System.out.println("4. 退出");
            System.out.print("请输入选项：");

            int option = scanner.nextInt();
            scanner.nextLine(); // 读取换行符

            switch (option) {
                case 1:
                    showBooks();
                    break;
                case 2:
                    buyBook();
                    break;
                case 3:
                    checkout();
                    break;
                case 4:
                    exit = true;
                    break;
                default:
                    System.out.println("无效的选项，请重新输入！");
            }
        }
    }

    private void showBooks() {
        for (Map.Entry<String, Book> entry : bookCatalog.entrySet()) {
            Book book = entry.getValue();
            System.out.println("书名: " + book.getTitle() + " 作者: " + book.getAuthor() + " 价格: " + book.getPrice());
        }
    }

    private void buyBook() {
        System.out.print("请输入要购买的书名：");
        String bookName = scanner.nextLine();
        Book book = bookCatalog.get(bookName);
        if (book != null) {
            int quantity = 0;
            while (quantity <= 0) {
                System.out.print("请输入购买数量：");
                try {
                    quantity = scanner.nextInt();
                    if (quantity <= 0) {
                        System.out.println("数量必须大于0，请重新输入！");
                    }
                } catch (Exception e) {
                    System.out.println("输入错误，请输入一个有效的数量！");
                    scanner.next(); // 清除错误输入
                }
            }
            shoppingCart.put(bookName, shoppingCart.getOrDefault(bookName, 0) + quantity);
            System.out.println("已添加 " + quantity + " 本 " + bookName + " 到购物车。");
        } else {
            System.out.println("抱歉，我们没有这本书。");
        }
    }

    private void checkout() {
        if (shoppingCart.isEmpty()) {
            System.out.println("您的购物车是空的。");
            return;
        }
        System.out.println("结算中...");
        for (Map.Entry<String, Integer> entry : shoppingCart.entrySet()) {
            Book book = bookCatalog.get(entry.getKey());
            int quantity = entry.getValue();
            double totalPrice = book.getPrice() * quantity;
            System.out.println("书名: " + book.getTitle() + " 数量: " + quantity + " 总价: " + totalPrice);
        }
        shoppingCart.clear();
        System.out.println("结算完成，感谢您的购买！");
    }
}

class Book {
    private String title;
    private String author;
    private double price;

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

    public String getTitle() {
        return title;
    }

    public String getAuthor() {
        return author;
    }

    public double getPrice() {
        return price;
    }
}

在这个简单的购书系统中，我们定义了两个类：`BookStore`和`Book`。`BookStore`类包含了图书目录和购物车的管理，以及主方法。`Book`类用于存储图书信息。系统提供了查看图书、购买图书和结算的功能。

请注意，这个示例是一个非常基础的实现，没有考虑错误处理、持久化存储和用户输入的复杂情况。在实际应用中，你可能需要添加更多的功能和健壮性考虑，比如异常处理、图书库存管理、用户身份验证、支付处理等。