Java中在线购物清单小项目

class Product {
    String name;
    double price;
    int quantity;
<pre class='brush:java;toolbar:false;'>public Product(String name, double price, int quantity) {
    this.name = name;
    this.price = price;
    this.quantity = quantity;
}

// 计算单项总价
public double getTotal() {
    return price * quantity;
}

@Override
public String toString() {
    return "名称：" + name + "，单价：" + price + "元，数量：" + quantity + "，小计：" + getTotal() + "元";
}

import java.util.*;
<p>public class ShoppingCart {
private List<Product> items = new ArrayList<>();
private Scanner scanner = new Scanner(System.in);</p><pre class='brush:java;toolbar:false;'>public void start() {
    while (true) {
        System.out.println("\n--- 在线购物清单 ---");
        System.out.println("1. 添加商品");
        System.out.println("2. 查看清单");
        System.out.println("3. 删除商品");
        System.out.println("4. 计算总价");
        System.out.println("5. 退出");
        System.out.print("请选择操作：");

        int choice = scanner.nextInt();
        scanner.nextLine(); // 消费换行符

        switch (choice) {
            case 1 -> addProduct();
            case 2 -> viewCart();
            case 3 -> removeProduct();
            case 4 -> calculateTotal();
            case 5 -> {
                System.out.println("感谢使用！");
                return;
            }
            default -> System.out.println("无效选择，请重试。");
        }
    }
}

private void addProduct() {
    System.out.print("输入商品名称：");
    String name = scanner.nextLine();
    System.out.print("输入单价（元）：");
    double price = scanner.nextDouble();
    System.out.print("输入数量：");
    int quantity = scanner.nextInt();
    scanner.nextLine();

    items.add(new Product(name, price, quantity));
    System.out.println("✅ " + name + " 已添加到购物车。");
}

private void viewCart() {
    if (items.isEmpty()) {
        System.out.println("购物车为空。");
        return;
    }
    System.out.println("\n? 当前购物清单：");
    for (int i = 0; i < items.size(); i++) {
        System.out.println((i + 1) + ". " + items.get(i));
    }
}

private void removeProduct() {
    viewCart();
    if (items.isEmpty()) return;

    System.out.print("输入要删除的商品编号：");
    int index = scanner.nextInt() - 1;
    if (index >= 0 && index < items.size()) {
        Product removed = items.remove(index);
        System.out.println("?️ 已删除：" + removed.name);
    } else {
        System.out.println("❌ 编号无效！");
    }
}

private void calculateTotal() {
    double total = items.stream().mapToDouble(Product::getTotal).sum();
    System.out.printf("? 当前总金额：%.2f 元\n", total);
}

public class Main {
    public static void main(String[] args) {
        new ShoppingCart().start();
    }
}

--- 在线购物清单 ---
1. 添加商品
2. 查看清单
3. 删除商品
4. 计算总价
5. 退出
请选择操作：1
输入商品名称：苹果
输入单价（元）：5.5
输入数量：3
✅ 苹果 已添加到购物车。