用java分别编写两个类Point2D，Point3D来表示二维空间和三维空间的点怎么做？
/*
* Project: 空间点
* Author: searchpcc(xixi,11级,20112866)
* File: TuXing.java
* Instruction: 主程序
* Time: 2012-11-07
*/
class Point2D{
int x;
int y;
public Point2D(){
}
public Point2D(int x, int y){
this.x = x;
this.y = y;
}
public void offset(int a, int b){
x = a;
y = b;
this.x = this.x + 1;
this.y = this.y + 1;
System.out.print(x);
System.out.print(y);
}
double distan(Point2D p1, Point2D p2){
return(Math.sqrt((p1.x-p2.x)*(p1.x-p2.x)+(p1.y-p2.y)*(p1.y-p2.y)));
}
}
class Point3D extends Point2D{
int z;
public Point3D(int x, int y, int z){
super(x, y);
this.z = z;
}
public Point3D(){
}
public Point3D(Point2D p, int z){
super(p.x, p.y);
this.z = z;
}
public void offset(int a, int b,int c){
x = a;
y = b;
z = c;
this.x = this.x + 1;
this.y = this.y + 1;
this.z = this.z + 1;
}
double distan(Point3D p1, Point3D p2){
return(Math.sqrt((p1.x-p2.x)*(p1.x-p2.x)+(p1.y-p2.y)*(p1.y-p2.y)+(p1.z-p2.z)*(p1.z-p2.z)));
}
}
public class KongJian1{
public static void main(String[] args){
Point2D p1 = new Point2D(3,3);
p1.offset(3, 3);
Point2D p2 = new Point2D(2,2);
Point3D p3 = new Point3D(4,4,4);
p3.offset(4,2,3);//可以进行移动
Point3D p4 = new Point3D(5,5,5);
System.out.println("p1和p2之间的距离为：");
System.out.println(new Point2D().distan(p1,p2));
System.out.println("p3和p4间的距离为：");
System.out.println(new Point3D().distan(p3,p4));
}
}
Java是一门面向对象编程语言，不仅吸收了C++语言的各种优点，还摒弃了C++里难以理解的多继承、指针等概念，因此Java语言具有功能强大和简单易用两个特征。Java语言作为静态面向对象编程语言的代表，极好地实现了面向对象理论，允许程序员以优雅的思维方式进行复杂的编程。
Java具有简单性、面向对象、分布式、健壮性、安全性、平台独立与可移植性、多线程、动态性等特点。Java可以编写桌面应用程序、Web应用程序、分布式系统和嵌入式系统应用程序等。
