Java8:将List<Product>>合并到一个列表中

import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;

public class Main {
    public static void main(String[] args) {
        List<Product> list1 = new ArrayList<>();
        list1.add(new Product("A", 10));
        list1.add(new Product("B", 20));

        List<Product> list2 = new ArrayList<>();
        list2.add(new Product("C", 30));
        list2.add(new Product("D", 40));

        List<Product> list3 = new ArrayList<>();
        list3.add(new Product("E", 50));
        list3.add(new Product("F", 60));

        List<List<Product>> listOfLists = new ArrayList<>();
        listOfLists.add(list1);
        listOfLists.add(list2);
        listOfLists.add(list3);

        List<Product> mergedList = listOfLists.stream()
                .flatMap(List::stream)
                .collect(Collectors.toList());

        System.out.println(mergedList);
    }
}

class Product {
    private String name;
    private int price;

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

    public String getName() {
        return name;
    }

    public int getPrice() {
        return price;
    }

    @Override
    public String toString() {
        return "Product{" +
                "name='" + name + '\'' +
                ", price=" + price +
                '}';
    }
}

[Product{name='A', price=10}, Product{name='B', price=20}, Product{name='C', price=30}, Product{name='D', price=40}, Product{name='E', price=50}, Product{name='F', price=60}]