求高手用JAVA幫我設計一個完整的Point類？

你好，程序如下：

public class Point {

double x1,x2,y1,y2;

double d,x3,y3;

Point(double x1,double y1,double x2,double y2){//構造方法

this.x1 = x1;

this.x2 = x2;

this.y1 = y1;

this.y2 = y2;

}

void TestPoint(){//求距離和中點坐標

x3 = (x1 + x2)/2;

y3 = (y1 + y2)/2;

d = Math.sqrt((x1 - x2)*(x1 - x2) + (y1 - y2)*(y1 - y2));

System.out.println("(" + x3 + ","+ y3 + ")");

System.out.println(d);

}

public static void main(String[] args) {

Point p = new Point(1,1,2,2);

p.TestPoint();

}

}

如果還有其他要求的話，我再改進一下。