用Java写一个餐饮管理系统

好的，下面是一个简单的餐饮管理系统的Java代码示例。该系统包括菜品管理、订单管理和库存管理三个模块。

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

public class RestaurantManagementSystem {
    private static Scanner scanner = new Scanner(System.in);
    private static Map<Integer, Dish> dishes = new HashMap<>();
    private static List<Order> orders = new ArrayList<>();
    private static int orderCounter = 1;
    private static int stock = 100;

    public static void main(String[] args) {
        while (true) {
            System.out.println("请选择操作：");
            System.out.println("1. 菜品管理");
            System.out.println("2. 订单管理");
            System.out.println("3. 库存管理");
            System.out.println("4. 退出");
            int choice = scanner.nextInt();
            switch (choice) {
                case 1:
                    dishManagement();
                    break;
                case 2:
                    orderManagement();
                    break;
                case 3:
                    stockManagement();
                    break;
                case 4:
                    System.exit(0);
                default:
                    System.out.println("无效的选择。");
                    break;
            }
        }
    }

    private static void dishManagement() {
        while (true) {
            System.out.println("请选择操作：");
            System.out.println("1. 添加菜品");
            System.out.println("2. 修改菜品");
            System.out.println("3. 删除菜品");
            System.out.println("4. 查看菜品");
            System.out.println("5. 返回上级菜单");
            int choice = scanner.nextInt();
            switch (choice) {
                case 1:
                    addDish();
                    break;
                case 2:
                    modifyDish();
                    break;
                case 3:
                    deleteDish();
                    break;
                case 4:
                    viewDishes();
                    break;
                case 5:
                    return;
                default:
                    System.out.println("无效的选择。");
                    break;
            }
        }
    }

    private static void addDish() {
        System.out.println("请输入菜品名称：");
        String name = scanner.next();
        System.out.println("请输入菜品价格：");
        double price = scanner.nextDouble();
        Dish dish = new Dish(name, price);
        dishes.put(dish.getId(), dish);
        System.out.println("菜品添加成功。");
    }

    private static void modifyDish() {
        System.out.println("请输入要修改的菜品编号：");
        int id = scanner.nextInt();
        Dish dish = dishes.get(id);
        if (dish == null) {
            System.out.println("菜品不存在。");
            return;
        }
        System.out.println("请输入新的菜品名称（不修改请按回车）：");
        String name = scanner.nextLine().trim();
        if (!name.isEmpty()) {
            dish.setName(name);
        }
        System.out.println("请输入新的菜品价格（不修改请按回车）：");
        String priceStr = scanner.nextLine().trim();
        if (!priceStr.isEmpty()) {
            double price = Double.parseDouble(priceStr);
            dish.setPrice(price);
        }
        System.out.println("菜品修改成功。");
    }

    private static void deleteDish() {
        System.out.println("请输入要删除的菜品编号：");
        int id = scanner.nextInt();
        Dish dish = dishes.get(id);
        if (dish == null) {
            System.out.println("菜品不存在。");
            return;
        }
        dishes.remove(id);
        System.out.println("菜品删除成功。");
    }

    private static void viewDishes() {
        System.out.println("菜品列表：");
        System.out.println("编号\t名称\t价格");
        for (Dish dish : dishes.values()) {
            System.out.println(dish.getId() + "\t" + dish.getName() + "\t" + dish.getPrice());
        }
    }

    private static void orderManagement() {
        while (true) {
            System.out.println("请选择操作：");
            System.out.println("1. 下单");
            System.out.println("2. 查看订单");
            System.out.println("3. 返回上级菜单");
            int choice = scanner.nextInt();
            switch (choice) {
                case 1:
                    placeOrder();
                    break;
                case 2:
                    viewOrders();
                    break;
                case 3:
                    return;
                default:
                    System.out.println("无效的选择。");
                    break;
            }
        }
    }

    private static void placeOrder() {
        System.out.println("请输入菜品编号和数量（以空格分隔，多个菜品以逗号分隔）：");
        String input = scanner.next();
        String[] dishInputs = input.split(",");
        Order order = new Order(orderCounter++);
        for (String dishInput : dishInputs) {
            String[] parts = dishInput.split(" ");
            int id = Integer.parseInt(parts[0]);
            int quantity = Integer.parseInt(parts[1]);
            Dish dish = dishes.get(id);
            if (dish == null) {
                System.out.println("菜品不存在。");
                return;
            }
            if (quantity > stock) {
                System.out.println("库存不足。");
                return;
            }
            order.addDish(dish, quantity);
            stock -= quantity;
        }
        orders.add(order);
        System.out.println("下单成功，订单编号为 " + order.getId() + "。");
    }

    private static void viewOrders() {
        System.out.println("订单列表：");
        System.out.println("编号\t总价\t菜品");
        for (Order order : orders) {
            System.out.print(order.getId() + "\t" + order.getTotalPrice() + "\t");
            for (OrderItem item : order.getItems()) {
                System.out.print(item.getDish().getName() + "*" + item.getQuantity() + ",");
            }
            System.out.println();
        }
    }

    private static void stockManagement() {
        while (true) {
            System.out.println("请选择操作：");
            System.out.println("1. 查看库存");
            System.out.println("2. 入库");
            System.out.println("3. 出库");
            System.out.println("4. 返回上级菜单");
            int choice = scanner.nextInt();
            switch (choice) {
                case 1:
                    viewStock();
                    break;
                case 2:
                    addStock();
                    break;
                case 3:
                    reduceStock();
                    break;
                case 4:
                    return;
                default:
                    System.out.println("无效的选择。");
                    break;
            }
        }
    }

    private static void viewStock() {
        System.out.println("当前库存为：" + stock);
    }

    private static void addStock() {
        System.out.println("请输入入库数量：");
        int quantity = scanner.nextInt();
        stock += quantity;
        System.out.println("入库成功，当前库存为：" + stock);
    }

    private static void reduceStock() {
        System.out.println("请输入出库数量：");
        int quantity = scanner.nextInt();
        if (quantity > stock) {
            System.out.println("库存不足。");
            return;
        }
        stock -= quantity;
        System.out.println("出库成功，当前库存为：" + stock);
    }
}

class Dish {
    private static int counter = 1;
    private int id;
    private String name;
    private double price;

    public Dish(String name, double price) {
        this.id = counter++;
        this.name = name;
        this.price = price;
    }

    public int getId() {
        return id;
    }

    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;
    }
}

class Order {
    private static int counter = 1;
    private int id;
    private List<OrderItem> items;

    public Order(int id) {
        this.id = counter++;
        this.items = new ArrayList<>();
    }

    public int getId() {
        return id;
    }

    public void addDish(Dish dish, int quantity) {
        OrderItem item = new OrderItem(dish, quantity);
        items.add(item);
    }

    public double getTotalPrice() {
        double totalPrice = 0;
        for (OrderItem item : items) {
            totalPrice += item.getDish().getPrice() * item.getQuantity();
        }
        return totalPrice;
    }

    public List<OrderItem> getItems() {
        return items;
    }
}

class OrderItem {
    private Dish dish;
    private int quantity;

    public OrderItem(Dish dish, int quantity) {
        this.dish = dish;
        this.quantity = quantity;
    }

    public Dish getDish() {
        return dish;
    }

    public int getQuantity() {
        return quantity;
    }
}

这个餐饮管理系统具有以下功能：

1. 菜品管理：添加、修改、删除、查看菜品。

2. 订单管理：下单、查看订单。

3. 库存管理：查看库存、入库、出库。

你可以在此基础上进行扩展，添加更多功能。