用java写一个网上书店管理系统

好的，下面是一个简单的网上书店管理系统的Java代码，包含书籍信息的添加、删除、修改和查询功能：

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

public class OnlineBookstore {
    private ArrayList<Book> books;
    private Scanner scanner;

    public OnlineBookstore() {
        books = new ArrayList<>();
        scanner = new Scanner(System.in);
    }

    public void addBook() {
        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();
        scanner.nextLine();
        Book book = new Book(name, author, price);
        books.add(book);
        System.out.println("添加成功！");
    }

    public void deleteBook() {
        System.out.print("请输入要删除的书名：");
        String name = scanner.nextLine();
        for (Book book : books) {
            if (book.getName().equals(name)) {
                books.remove(book);
                System.out.println("删除成功！");
                return;
            }
        }
        System.out.println("没有找到该书！");
    }

    public void modifyBook() {
        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("请输入修改后的书名：");
                String newName = scanner.nextLine();
                System.out.print("请输入修改后的作者：");
                String author = scanner.nextLine();
                System.out.print("请输入修改后的价格：");
                double price = scanner.nextDouble();
                scanner.nextLine();
                book.setName(newName);
                book.setAuthor(author);
                book.setPrice(price);
                System.out.println("修改成功！");
                return;
            }
        }
        System.out.println("没有找到该书！");
    }

    public void searchBook() {
        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("查询结果：");
                System.out.println("书名：" + book.getName());
                System.out.println("作者：" + book.getAuthor());
                System.out.println("价格：" + book.getPrice());
                return;
            }
        }
        System.out.println("没有找到该书！");
    }

    public void displayBooks() {
        System.out.println("所有书籍信息：");
        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("---------------");
        }
    }

    public static void main(String[] args) {
        OnlineBookstore bookstore = new OnlineBookstore();
        while (true) {
            System.out.println("请选择操作：");
            System.out.println("1.添加书籍");
            System.out.println("2.删除书籍");
            System.out.println("3.修改书籍");
            System.out.println("4.查询书籍");
            System.out.println("5.显示所有书籍信息");
            System.out.println("6.退出");
            int choice = bookstore.scanner.nextInt();
            bookstore.scanner.nextLine();
            switch (choice) {
                case 1:
                    bookstore.addBook();
                    break;
                case 2:
                    bookstore.deleteBook();
                    break;
                case 3:
                    bookstore.modifyBook();
                    break;
                case 4:
                    bookstore.searchBook();
                    break;
                case 5:
                    bookstore.displayBooks();
                    break;
                case 6:
                    System.exit(0);
                default:
                    System.out.println("请输入正确的选项！");
            }
        }
    }
}

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

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public double getPrice() {
        return price;
    }

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

注意，这只是一个简单的示例，实际开发中还需要考虑到更多的功能和异常处理。