（1）定义Point（点）、Circle（圆形）、Square（正方形）类。点信息包括x，y坐标。圆信息包括圆心坐标和半径。正方形信息包括中心坐标和边长。用关联（Point对象作为Circle和Square的成员）和继承（Circle和Square分别继承Point）两种方法实现并测试。
import java.util.Scanner;public class Main {public static void main(String args[]) {Scanner sc = new Scanner(System.in);System.out.println("请输入p的x坐标:");double x = sc.nextDouble();System.out.println("请输入p的y坐标:");double y = sc.nextDouble();System.out.println("请输入r或a的值:");double a = sc.nextDouble();Circle1 c1 = new Circle1(x, y, a);System.out.println(c1);Square1 s1 = new Square1(x, y, a);System.out.println(s1);Circle2 c2 = new Circle2(x, y, a);System.out.println(c2);Square2 s2 = new Square2(x, y, a);System.out.println(s2);}
}class Point { // 关联：Point对象作为Circle1和Square1的成员// 继承：Circle2和Square2分别继承Pointpublic Point(double x, double y) {super();this.x = x;this.y = y;}double x, y;
}class Circle1 { // Point对象作为Circle1和Square1的成员Point p;double r;Circle1(double x, double y, double r) {this.p = new Point(x, y);this.r = r;}@Overridepublic String toString() {return "关联Circle1: p=" + p + ", r=" + r;}
}class Square1 { // Point对象作为Circle1和Square1的成员Point p;double a;Square1(double x, double y, double a) {this.p = new Point(x, y);this.a = a;}@Overridepublic String toString() {return "关联Square1: p=" + p + ", a=" + a;}
}class Circle2 extends Point { // Circle2和Square2分别继承Pointdouble r;Circle2(double x, double y, double r) {super(x, y);this.r = r;}@Overridepublic String toString() {return "继承Square2: " + "p=(" + x + "," + y + "),r=" + r;}
}class Square2 extends Point { // Circle2和Square2分别继承Pointdouble a;Square2(double x, double y, double a) {super(x, y);this.a = a;}@Overridepublic String toString() {return "继承Square2: " + "p=(" + x + "," + y + "),a=" + a;}
}（2）定义抽象类Shape（形状），包含形状名字属性及相应构造方法。
定义两个接口，一个接口IArea定义求面积的方法，一个接口IVolume定义求体积的方法。
定义Shape类的子类矩形（Rectangle）类，实现IArea接口。
定义长方体类同时实现IArea（求表面积）和IVolume接口。
在main方法中测试。
import java.util.Scanner;public class Main {public static void main(String[] args) {Scanner sc = new Scanner(System.in);System.out.println("请输入形状:");String shape = sc.next();System.out.println("请分别输入矩形长、宽:");double x = sc.nextDouble();double y = sc.nextDouble();Rectangle rec1 = new Rectangle(shape, x, y);System.out.println("矩形的面积为:" + rec1.area());System.out.println("请分别输入长方体长、宽、高:");double l = sc.nextDouble();double w = sc.nextDouble();double h = sc.nextDouble();T t1 = new T("长方体", l, w, h);System.out.println("长方体的表面积为:" + t1.area());System.out.println("长方体的体积为:" + t1.v());}
}abstract class Shape { // 定义抽象类Shape(形状),包含形状名字属性及相应构造方法。String name;public Shape(String name) { // 形状名字super();this.name = name;}
}interface IArea { // 面积double area();
}interface IVolume { // 体积double v();
}class Rectangle extends Shape implements IArea { // Shape子类Rectangle矩形类double x, y;public Rectangle(String name, double x, double y) {super(name);this.x = x;this.y = y;}@Overridepublic double area() {// TODO Auto-generated method stubreturn this.x * this.y;}
}class T extends Shape implements IArea, IVolume { // T长方体double len, wid, h; // len长、wid宽、h高public T(String name, double len, double wid, double h) {super(name);this.len = len;this.wid = wid;this.h = h;}@Overridepublic double area() { // 长方体求表面积// TODO Auto-generated method stubreturn (len * wid + len * h + h * wid) * 2;}@Overridepublic double v() { // T长方体求体积// TODO Auto-generated method stubreturn len * wid * h;}
}