网上书店管理系统 java

网上书店管理系统是一个电子商务平台，用户可以在该平台上购买图书、管理个人信息、查询订单等。以下是一个简单的网上书店管理系统的Java代码示例：

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

class Book {
    private String name;
    private String author;
    private double price;
    private int num;

    public Book(String name, String author, double price, int num) {
        this.name = name;
        this.author = author;
        this.price = price;
        this.num = num;
    }

    public String getName() {
        return name;
    }

    public String getAuthor() {
        return author;
    }

    public double getPrice() {
        return price;
    }

    public int getNum() {
        return num;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    public void setNum(int num) {
        this.num = num;
    }
}

class User {
    private String username;
    private String password;

    public User(String username, String password) {
        this.username = username;
        this.password = password;
    }

    public String getUsername() {
        return username;
    }

    public String getPassword() {
        return password;
    }
}

public class OnlineBookstore {
    private ArrayList<Book> books;
    private ArrayList<User> users;

    public OnlineBookstore() {
        books = new ArrayList<>();
        users = new ArrayList<>();
    }

    public void login() {
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入用户名：");
        String username = scanner.nextLine();
        System.out.print("请输入密码：");
        String password = scanner.nextLine();

        for (User user : users) {
            if (user.getUsername().equals(username) && user.getPassword().equals(password)) {
                System.out.println("登录成功！");
                return;
            }
        }

        System.out.println("用户名或密码错误，请重新输入！");
        login();
    }

    public void addBook() {
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入书名：");
        String name = scanner.nextLine();
        System.out.print("请输入作者：");
        String author = scanner.nextLine();
        System.out.print("请输入价格：");
        double price = scanner.nextDouble();
        System.out.print("请输入数量：");
        int num = scanner.nextInt();

        books.add(new Book(name, author, price, num));

        System.out.println("添加成功！");
    }

    public void editBook() {
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入要修改的书名：");
        String name = scanner.nextLine();

        for (Book book : books) {
            if (book.getName().equals(name)) {
                System.out.print("请输入修改后的价格：");
                double price = scanner.nextDouble();
                System.out.print("请输入修改后的数量：");
                int num = scanner.nextInt();
                book.setPrice(price);
                book.setNum(num);
                System.out.println("修改成功！");
                return;
            }
        }

        System.out.println("没有找到该书籍！");
    }

    public void searchBook() {
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入要查询的书名：");
        String name = scanner.nextLine();

        for (Book book : books) {
            if (book.getName().equals(name)) {
                System.out.println("书名：" + book.getName());
                System.out.println("作者：" + book.getAuthor());
                System.out.println("价格：" + book.getPrice());
                System.out.println("数量：" + book.getNum());
                return;
            }
        }

        System.out.println("没有找到该书籍！");
    }

    public void displayBooks() {
        for (Book book : books) {
            System.out.println("书名：" + book.getName());
            System.out.println("作者：" + book.getAuthor());
            System.out.println("价格：" + book.getPrice());
            System.out.println("数量：" + book.getNum());
            System.out.println();
        }
    }

    public static void main(String[] args) {
        OnlineBookstore bookstore = new OnlineBookstore();
        bookstore.users.add(new User("admin", "admin"));
        bookstore.login();

        Scanner scanner = new Scanner(System.in);
        while (true) {
            System.out.println("1. 添加书籍");
            System.out.println("2. 修改书籍");
            System.out.println("3. 查询书籍");
            System.out.println("4. 显示所有书籍");
            System.out.println("5. 退出");
            System.out.print("请输入操作编号：");
            int choice = scanner.nextInt();

            switch (choice) {
                case 1:
                    bookstore.addBook();
                    break;
                case 2:
                    bookstore.editBook();
                    break;
                case 3:
                    bookstore.searchBook();
                    break;
                case 4:
                    bookstore.displayBooks();
                    break;
                case 5:
                    System.exit(0);
                default:
                    System.out.println("输入错误，请重新输入！");
            }
        }
    }
}

该示例实现了以下功能：

1. 用户登录（默认用户名为admin，密码为admin）。
2. 添加书籍。
3. 修改书籍。
4. 查询书籍。
5. 显示所有书籍。

注意：该示例仅供参考，实际项目中需要根据具体需求进行相应的修改和完善。