Question

所以我需要为容器类实现一个getCurrentVolumeInCCs方法，但是我对如何实现它有点困惑。此外，我在Glass和Cup类中获得了正确的音量值，但是当我调用Vessel类中的任何其他方法时，这些值都不会被结转。我猜它是因为它们存储在子类中而不能在基类中使用，我是对的吗？

船只类（摘要）

package containers;

public abstract class Vessel {
    private double volume; 
    private double currentVolume;
    public Vessel() {
        volume = 0;
        currentVolume = 0;
    }

    abstract double getVolumeInCC();

    public double getCurrentContents() {


        return currentVolume;
    }

    public double drink(double amountToDrink) {
        double volumeLeft; 

        System.out.println("you drank " + amountToDrink + " CCs");
        volumeLeft = volume - amountToDrink;

        return volumeLeft;
    }

    public double fill(double amountPoured) {
        double volumeAdded = amountPoured;
        double volumeSpilled = 0;

        System.out.println("you poured " + amountPoured + " CCs");
        if(volumeAdded > volume) {
            volumeSpilled = amountPoured - volume;
            System.out.println("you spilled " + volumeSpilled);

        }
        return volumeAdded;
    }

}

玻璃类

package containers;

public class Glass extends Vessel{
    private double volume;
    private double radiusBase;
    private double height; 

    public Glass() {}

    public Glass(double r, double h) {
        this.radiusBase = r;
        this.height = h;
    }

    @Override
    double getVolumeInCC() {
        volume = (Math.PI)*(Math.pow(radiusBase, 2))*height;

        return volume;
    }
}

杯赛类

package containers;

public class Cup extends Vessel {
    private double volume;
    private double radiusLip;


    public Cup(double r) { 
        volume = 0;
        this.radiusLip = r;

    }

    @Override
    double getVolumeInCC() {
        volume = (0.5)*(Math.PI)*(Math.pow(radiusLip, 3))*(4/3);

        return volume;
    }

}

Answer 1

您在子类中volume隐藏Vessel，因为它是private字段。我相信你想在volume中保护currentVolume和Vessel，

protected double volume; 
protected double currentVolume;

此外，您应该从子类中删除private double volume（这样您就不会影响他们现在从Vessel继承的字段。）

java中的简单抽象类

1 个答案: