用java写一个超市管理系统长一点

好的，我可以为您提供一个基本的超市管理系统的Java代码框架，您可以在此基础上进行修改和完善。代码如下：

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

public class SupermarketManagementSystem {
    
    // 商品类
    class Commodity {
        private String name; // 商品名称
        private double price; // 商品价格
        private int inventory; // 商品库存
        
        public Commodity(String name, double price, int inventory) {
            this.name = name;
            this.price = price;
            this.inventory = inventory;
        }
        
        public String getName() {
            return name;
        }
        
        public void setName(String name) {
            this.name = name;
        }
        
        public double getPrice() {
            return price;
        }
        
        public void setPrice(double price) {
            this.price = price;
        }
        
        public int getInventory() {
            return inventory;
        }
        
        public void setInventory(int inventory) {
            this.inventory = inventory;
        }
    }
    
    // 购物车类
    class ShoppingCart {
        private ArrayList<Commodity> goods = new ArrayList<>(); // 商品列表
        
        public void add(Commodity commodity) {
            goods.add(commodity);
        }
        
        public void remove(Commodity commodity) {
            goods.remove(commodity);
        }
        
        public void clear() {
            goods.clear();
        }
        
        public ArrayList<Commodity> getGoods() {
            return goods;
        }
    }
    
    // 超市类
    class Supermarket {
        private ArrayList<Commodity> goods = new ArrayList<>(); // 商品列表
        private double balance; // 超市余额
        
        public Supermarket(double balance) {
            this.balance = balance;
        }
        
        public void add(Commodity commodity) {
            goods.add(commodity);
        }
        
        public void remove(Commodity commodity) {
            goods.remove(commodity);
        }
        
        public ArrayList<Commodity> getGoods() {
            return goods;
        }
        
        public double getBalance() {
            return balance;
        }
        
        public void setBalance(double balance) {
            this.balance = balance;
        }
    }
    
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        SupermarketManagementSystem system = new SupermarketManagementSystem();
        Supermarket supermarket = new Supermarket(100000); // 初始化超市，余额为100000元
        ShoppingCart cart = new ShoppingCart(); // 初始化购物车
        
        // 添加商品到超市
        supermarket.add(system.new Commodity("可乐", 3.5, 100));
        supermarket.add(system.new Commodity("雪碧", 3.5, 100));
        supermarket.add(system.new Commodity("薯片", 5, 50));
        supermarket.add(system.new Commodity("巧克力", 10, 20));
        // ...

        while (true) {
            // 显示商品列表
            System.out.println("商品列表：");
            ArrayList<Commodity> goods = supermarket.getGoods();
            for (int i = 0; i < goods.size(); i++) {
                Commodity commodity = goods.get(i);
                System.out.println((i + 1) + ". " + commodity.getName() + "，单价：" + commodity.getPrice() + "元，库存：" + commodity.getInventory() + "件");
            }
            System.out.println();

            // 显示购物车
            System.out.println("购物车：");
            ArrayList<Commodity> cartGoods = cart.getGoods();
            for (int i = 0; i < cartGoods.size(); i++) {
                Commodity commodity = cartGoods.get(i);
                System.out.println((i + 1) + ". " + commodity.getName() + "，单价：" + commodity.getPrice() + "元，数量：" + 1);
            }
            System.out.println();

            // 显示余额
            System.out.println("余额：" + supermarket.getBalance() + "元");
            System.out.println();

            // 购物操作
            System.out.println("请选择操作：");
            System.out.println("1. 添加商品到购物车");
            System.out.println("2. 从购物车中删除商品");
            System.out.println("3. 结算");
            String choice = scanner.nextLine();
            System.out.println();

            switch (choice) {
                case "1":
                    System.out.println("请输入商品编号：");
                    int index = Integer.parseInt(scanner.nextLine()) - 1;
                    Commodity commodity = goods.get(index);
                    if (commodity.getInventory() > 0) { // 判断库存是否充足
                        cart.add(commodity); // 添加商品到购物车
                        commodity.setInventory(commodity.getInventory() - 1); // 减少商品库存
                        System.out.println("已添加商品：" + commodity.getName());
                    } else {
                        System.out.println("库存不足！");
                    }
                    break;
                case "2":
                    System.out.println("请输入商品编号：");
                    index = Integer.parseInt(scanner.nextLine()) - 1;
                    commodity = cartGoods.get(index);
                    cart.remove(commodity); // 从购物车中删除商品
                    commodity.setInventory(commodity.getInventory() + 1); // 增加商品库存
                    System.out.println("已删除商品：" + commodity.getName());
                    break;
                case "3":
                    double totalPrice = 0;
                    cartGoods = cart.getGoods();
                    for (int i = 0; i < cartGoods.size(); i++) {
                        commodity = cartGoods.get(i);
                        totalPrice += commodity.getPrice();
                    }
                    if (totalPrice > supermarket.getBalance()) { // 判断余额是否充足
                        System.out.println("余额不足！");
                    } else {
                        // 扣除余额
                        supermarket.setBalance(supermarket.getBalance() - totalPrice);
                        // 清空购物车
                        cart.clear();
                        System.out.println("结算成功！");
                    }
                    break;
                default:
                    System.out.println("输入有误，请重新输入！");
                    break;
            }

            System.out.println();
        }
    }
}

该代码实现了以下基本功能：

1. 显示超市商品列表。
2. 添加商品到购物车。
3. 从购物车中删除商品。
4. 结算购物车中的商品，并扣除超市余额。