用java语言写一个茶叶销售系统

好的，以下是一个简单的使用Java语言编写的茶叶销售系统代码示例，实现了添加产品，展示产品列表，购买产品等基本功能：

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

class Product {
    String name;
    double price;
    int stock;

    Product(String name, double price, int stock) {
        this.name = name;
        this.price = price;
        this.stock = stock;
    }
}

class TeaSalesSystem {
    ArrayList<Product> products;

    TeaSalesSystem() {
        products = new ArrayList<>();
    }

    void addProduct(String name, double price, int stock) {
        products.add(new Product(name, price, stock));
    }

    void showProducts() {
        System.out.println("Product list:");
        for (int i = 0; i < products.size(); i++) {
            Product product = products.get(i);
            System.out.println((i+1) + ". " + product.name + " - $" + product.price + " - " + product.stock + " in stock");
        }
    }

    void buyProduct(int index, int quantity) {
        Product product = products.get(index-1);
        if (product.stock < quantity) {
            System.out.println("Sorry, only " + product.stock + " left in stock");
            return;
        }
        double totalPrice = product.price * quantity;
        System.out.println("You have purchased " + quantity + " " + product.name + " for $" + totalPrice);
        product.stock -= quantity;
    }
}

public class Main {
    public static void main(String[] args) {
        TeaSalesSystem system = new TeaSalesSystem();
        system.addProduct("Green tea", 5.99, 10);
        system.addProduct("Black tea", 4.99, 15);
        system.addProduct("Oolong tea", 6.99, 8);

        system.showProducts();

        Scanner input = new Scanner(System.in);
        System.out.print("Enter product index to purchase: ");
        int index = input.nextInt();
        System.out.print("Enter quantity to purchase: ");
        int quantity = input.nextInt();

        system.buyProduct(index, quantity);

        system.showProducts();
    }
}

此代码创建了一个`Product`类来表示茶叶产品，以及一个`TeaSalesSystem`类来管理产品列表和购买操作。在`main()`方法中创建了一个系统实例，并添加了三种茶叶产品。`showProducts()`方法用于列出产品列表，`buyProduct()`方法用于购买产品并更新库存。使用`Scanner`类获取用户输入来选择要购买的产品和数量。