Java（包之间类的引用）

第一个包

package Mypack;public class Point {        public double x,y;        public Point(double a,double b)        {            x=a;            y=b;        }        public double distanceTo(Point p){            return Math.sqrt((x-p.x)*(x-p.x)+(y-p.y)*(y-p.y));      }}

第二个包

package Test;import Mypack.Point;public class UsePoint {    public static void main(String[] args)    {        Point p1=new Point(1.0,2.0);        Point p2=new Point(2.0, 5.5);        System.out.println("点p1坐标："+p1.x+","+p1.y);        System.out.println("点p2坐标："+p2.x+","+p2.y);        System.out.println("点p1到点p2的距离："+p1.distanceTo(p2));    }}

结果点p1坐标：1.0,2.0
点p2坐标：2.0,5.5
点p1到点p2的距离：3.640054944640259