image.png 

    1. package com.atguigu.exercise2;
    2. public class GeometricObject {//几何图形
    3.     // 属性
    4.     protected String color;// 颜色
    5.     protected double weight;// 重量
    6.     // 构造器
    7.     public GeometricObject(String color,double weight){
    8.   this.color = color;
    9.   this.weight = weight;
    10.     }
    12.     //方法
    13.     public String getColor() {
    14.   return color;
    15.     }
    16.     public void setColor(String color) {
    17.   this.color = color;
    18.     }
    19.     public double getWeight() {
    20.   return weight;
    21.     }
    22.     public void setWeight(double weight) {
    23.   this.weight = weight;
    24.     }
    26.     public double findArea(){
    27.   return 0;
    28.     }
    29. }
    1. package com.atguigu.exercise2;
    2. public class Ciecle extends GeometricObject{
    3.     //属性
    4.     private double radius;
    6.     //构造器
    7.     public Ciecle(double radius,String color,double weight){
    8.   super(color, weight);//父类中的属性
    9.   this.radius = radius;
    10.     }
    11.     //方法
    12.     public double getRadius() {
    13.   return radius;
    14.     }
    15.     public void setRadius(double radius) {
    16.   this.radius = radius;
    17.     }
    19.     public double findArea(){
    20.   return Math.PI*radius*radius;
    21.     }
    22. }
    1. package com.atguigu.exercise2;
    2. public class MyRectangle extends GeometricObject{//矩形
    4.     //属性
    5.     private double width;
    6.     private double height;
    8.     //构造器
    9.     public MyRectangle(double width,double height,String color,double weight){
    10.   super(color, weight);//父类中的属性
    11.   this.width = width;
    12.   this.height = height;
    13.     }
    15.     //方法
    16.     public double getWidth() {
    17.   return width;
    18.     }
    19.     public void setWidth(double width) {
    20.   this.width = width;
    21.     }
    22.     public double getHeight() {
    23.   return height;
    24.     }
    25.     public void setHeight(double height) {
    26.   this.height = height;
    27.     }
    29.     public double findArea(){
    30.   return width*height;
    31.     }
    32. }
    1. package com.atguigu.exercise2;
    2. public class GeometricTest {
    4.     public static void main(String[] args) {
    5.   GeometricTest test = new GeometricTest();
    7.   Ciecle c1 = new Ciecle(2.3,"red",1.0);
    8.   test.displayGeometricObject(c1);
    10.   Ciecle c2 = new Ciecle(3.3,"black",1.0);
    12.   System.out.println("c1和c2的面积是否相等："+test.equalsArea(c1,c2));
    13.     }
    14.     //测试两个对象的面积是否相等
    15.     public boolean equalsArea(GeometricObject o1,GeometricObject o2){
    16.       return o1.findArea() == o2.findArea();  
    17.   }
    18.     //计算面积
    19.     public void displayGeometricObject(GeometricObject o) {
    20.   System.out.println("面积为：" + o.findArea());
    21.     }
    22. }