定义一个是shape抽象类，利用他作为基类派生出Retangle，circle等具体形状类，已知，具体形状类均具有两个方法Getarea，Getcolor，分别用来得到形状的面积和颜色，最后编写一个测试程序对产生的类的功能进行验证，用java实现

抽象类Shape的实现：

public abstract class Shape {
    protected String color;

    public Shape(String color) {
        this.color = color;
    }

    public abstract double getArea();

    public String getColor() {
        return color;
    }
}

Rectangle类的实现：

public class Rectangle extends Shape {
    private double width;
    private double height;

    public Rectangle(double width, double height, String color) {
        super(color);
        this.width = width;
        this.height = height;
    }

    @Override
    public double getArea() {
        return width * height;
    }
}

Circle类的实现：

public class Circle extends Shape {
    private double radius;

    public Circle(double radius, String color) {
        super(color);
        this.radius = radius;
    }

    @Override
    public double getArea() {
        return Math.PI * radius * radius;
    }
}

测试程序的实现：

public class Test {
    public static void main(String[] args) {
        Shape shape1 = new Rectangle(5, 10, "red");
        Shape shape2 = new Circle(3, "blue");

        System.out.println("The area of the rectangle is " + shape1.getArea());
        System.out.println("The color of the rectangle is " + shape1.getColor());

        System.out.println("The area of the circle is " + shape2.getArea());
        System.out.println("The color of the circle is " + shape2.getColor());
    }
}

输出结果：

The area of the rectangle is 50.0
The color of the rectangle is red
The area of the circle is 28.274333882308138
The color of the circle is blue