1、设计一个水果运输货车，希望货车可以运输若干种水果。要求 Java 应用程序有 5 个类，名字分别是 Fruit、Apple、Orange、 Car 和 Test，其中 Fruit 类是抽象类，Apple 类和 Orange 类继承自 Fruit 类，Car 类是描述水果运输货车，Test 是测试主类

好的，这是一个很好的编程问题。以下是一个简单的实现：

Fruit.java：

public abstract class Fruit {
    protected String name;
    protected double weight;

    public Fruit(String name, double weight) {
        this.name = name;
        this.weight = weight;
    }

    public String getName() {
        return name;
    }

    public double getWeight() {
        return weight;
    }

    public abstract double getCost();
}

Apple.java：

public class Apple extends Fruit {
    public Apple(double weight) {
        super("Apple", weight);
    }

    public double getCost() {
        return weight * 2.0; // 假设每公斤苹果的价格是 2 元
    }
}

Orange.java：

public class Orange extends Fruit {
    public Orange(double weight) {
        super("Orange", weight);
    }

    public double getCost() {
        return weight * 1.5; // 假设每公斤橘子的价格是 1.5 元
    }
}

Car.java：

import java.util.ArrayList;

public class Car {
    private ArrayList<Fruit> fruits;

    public Car() {
        fruits = new ArrayList<Fruit>();
    }

    public void addFruit(Fruit fruit) {
        fruits.add(fruit);
    }

    public double getTotalCost() {
        double totalCost = 0.0;
        for (Fruit fruit : fruits) {
            totalCost += fruit.getCost();
        }
        return totalCost;
    }
}

Test.java：

public class Test {
    public static void main(String[] args) {
        Car car = new Car();
        car.addFruit(new Apple(2.5));
        car.addFruit(new Orange(3.0));
        System.out.println("Total cost: " + car.getTotalCost());
    }
}

这个程序可以创建一个水果运输货车，可以添加苹果和橘子，计算总成本。