java定义一个快递包裹类 Package ，并由此派生出普通包裹类和加急包裹类。要求： (1) Package 类应包含寄件人和收件人姓名、地址和包裹重量属性，按重量＊10计费。(2）普通包裹增加首重计费和超首重后部分的的每公斤计费单价属性，按首重＋超重＊每公斤计费单价计算总费用。 (3）加急包裹没有首重限制，但有加急起价费用属性，按加急起价费＋重 (4）为每个类添加 calculateCost 计算快递费用方法。编写测试程序，创建 量＊10＋加急公里数＊0.02计算总费用。 每种包裹类的对象并测试 calculateCost 方法。

好的，这是一个比较具体的编程问题，我可以为您提供一个Java的实现示例，您可以参考一下：

// 定义 Package 类
class Package {
    private String senderName;
    private String senderAddress;
    private String receiverName;
    private String receiverAddress;
    private double weight; // 单位为千克

    public Package(String senderName, String senderAddress, String receiverName, String receiverAddress, double weight) {
        this.senderName = senderName;
        this.senderAddress = senderAddress;
        this.receiverName = receiverName;
        this.receiverAddress = receiverAddress;
        this.weight = weight;
    }

    public double calculateCost() {
        return weight * 10;
    }

    // getter 和 setter 方法
}

// 定义普通包裹类
class OrdinaryPackage extends Package {
    private double firstWeight;
    private double excessFee; // 超出首重后的每公斤计费单价

    public OrdinaryPackage(String senderName, String senderAddress, String receiverName, String receiverAddress, double weight, double firstWeight, double excessFee) {
        super(senderName, senderAddress, receiverName, receiverAddress, weight);
        this.firstWeight = firstWeight;
        this.excessFee = excessFee;
    }

    public double calculateCost() {
        if (weight <= firstWeight) {
            return super.calculateCost();
        } else {
            return firstWeight * 10 + (weight - firstWeight) * excessFee;
        }
    }

    // getter 和 setter 方法
}

// 定义加急包裹类
class UrgentPackage extends Package {
    private double startingFee; // 加急起价费用

    public UrgentPackage(String senderName, String senderAddress, String receiverName, String receiverAddress, double weight, double startingFee) {
        super(senderName, senderAddress, receiverName, receiverAddress, weight);
        this.startingFee = startingFee;
    }

    public double calculateCost() {
        return startingFee + super.calculateCost();
    }

    // getter 和 setter 方法
}

// 测试程序
public class Main {
    public static void main(String[] args) {
        Package p1 = new Package("张三", "北京市朝阳区", "李四", "上海市浦东新区", 2.5);
        OrdinaryPackage op1 = new OrdinaryPackage("张三", "北京市朝阳区", "李四", "上海市浦东新区", 2.5, 1.0, 3.0);
        UrgentPackage up1 = new UrgentPackage("张三", "北京市朝阳区", "李四", "上海市浦东新区", 2.5, 50.0);

        System.out.println("普通包裹1的费用为：" + op1.calculateCost());
        System.out.println("加急包裹1的费用为：" + up1.calculateCost());
    }
}

在这个示例中，Package 类包含了寄件人和收件人姓名、地址和包裹重量属性，并定义了 calculateCost 方法用于计算快递费用。OrdinaryPackage 类和 UrgentPackage 类都继承了 Package 类，并在其基础上增加了额外的属性和 calculateCost 方法的实现。最后，在测试程序中创建了几个对象并调用了它们的 calculateCost 方法，输出了它们的费用。