java - 从另一个类(java)访问数据？

Question

我创建了一个“父”类(不确定这是否是正确的术语)，它代表 3d 空间中的一个点，如下所示:

public class Point3d {

    private double xCoord;
    private double yCoord;
    private double zCoord;


    public Point3d(double x,double y, double z ){
        xCoord = x;
        yCoord = y;
        zCoord = z;
    }

    public Point3d() {
        this (0,0,0);
    }


    public double getxCoord() {
        return xCoord;
    }


    public double getyCoord() {
        return yCoord;
    }



    public double getzCoord() {
        return zCoord;
    }

    public void setX(double val){
        xCoord= val;

    }
    public void setY(double val){
        yCoord= val;
    }
    public void setZ(double val){
        zCoord= val;
    }

}

我有两个类定义了两个不同的点(x，y，z)第一类:

package threedimpoint;

public class FirstPoint {

    public static void main(String[] args) {

        Point3d frst = new Point3d();

        frst.setX(0);
        frst.setY(0);
        frst.setZ(0);

        System.out.println("(" + frst.getxCoord() + "," + frst.getyCoord() + "," + frst.getzCoord() + ")");



    }

}

二等

package threedimpoint;

public class Secondpoint {

    public static void main(String[] args) {

        Point3d secnd = new Point3d();

        secnd.setX(2);
        secnd.setY(12);
        secnd.setZ(24);

        System.out.println("(" + secnd.getxCoord() + "," + secnd.getyCoord() + "," + secnd.getzCoord() + ")");

    }

}

现在我希望创建一个新类，它获取的信息是 x,y,z 坐标从第一类(公共(public)类第一点)以及从第二类(公共(public)类第二点)

并用它来计算两点之间的距离。

如何在新类(class)中访问该信息？

Answer 1

如果要计算两点之间的距离，可以在类Point3d中创建一个函数。例如:

public class Point3d {

    private double xCoord;
    private double yCoord;
    private double zCoord;


    public Point3d(double x,double y, double z ){
        xCoord = x;
        yCoord = y;
        zCoord = z;
    }

    public double calucateDistance(Point3d compareObj)
    { 
        // ......
    }
    //......
}

然后你只需要创建一个测试类，在测试类中你可以创建两个Point3d实例，例如:

public class Test{

   public static void main(String[] args) {

      Point3d first = new Point3d();        
      first .setX(0);

      first .setY(0);

      first .setZ(0); 

      Point3d second = new Point3d(); 

      second.setX(2);

      second.setY(12);

      second.setZ(24);

      double result = first.calucateDistance(second); 

   }
 }