在Java中如何实现购物清单自动汇总

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

public double getTotal() {
    return price * quantity;
}

// getter 方法（toString 可选）
public String getName() { return name; }
public double getPrice() { return price; }
public int getQuantity() { return quantity; }

@Override
public String toString() {
    return name + " × " + quantity + " = ¥" + String.format("%.2f", getTotal());
}

import java.util.ArrayList;
import java.util.List;
<p>List<Item> shoppingList = new ArrayList<>();
shoppingList.add(new Item("苹果", 5.5, 3));
shoppingList.add(new Item("牛奶", 12.0, 2));
shoppingList.add(new Item("面包", 8.0, 1));</p>

double totalAmount = 0.0;
for (Item item : shoppingList) {
    System.out.println(item);  // 打印每项明细
    totalAmount += item.getTotal();
}
System.out.println("总计：¥" + String.format("%.2f", totalAmount));

double total = shoppingList.stream()
    .mapToDouble(Item::getTotal)
    .sum();