定义一个抽象类（Shape），包括求周长getPerimeter和求面积getArea抽像方法，然后在子类中求长方形(Rectangje)和圆（Circle）的周长和面积。（请以txt文档形式提交代码或者） 1)完成Shape类，Circle类，Rectangle类的设计。 2）在测试类中定义一个Shape类型的数组存入几个Circle类对象和Rectange类对象，并利用一个环打印出所有图形的周长和面积。

以下是Java代码实现：

Shape.java

public abstract class Shape {
    public abstract double getPerimeter();
    public abstract double getArea();
}

Circle.java

public class Circle extends Shape {
    private double radius;

    public Circle(double radius) {
        this.radius = radius;
    }

    @Override
    public double getPerimeter() {
        return 2 * Math.PI * radius;
    }

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

Rectangle.java

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

    public Rectangle(double length, double width) {
        this.length = length;
        this.width = width;
    }

    @Override
    public double getPerimeter() {
        return 2 * (length + width);
    }

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

Test.java

public class Test {
    public static void main(String[] args) {
        Shape[] shapes = new Shape[3];
        shapes[0] = new Circle(5);
        shapes[1] = new Rectangle(4, 6);
        shapes[2] = new Circle(3);

        for (Shape shape : shapes) {
            System.out.println("Perimeter: " + shape.getPerimeter());
            System.out.println("Area: " + shape.getArea());
            System.out.println();
        }
    }
}

运行Test.java的输出结果为：

Perimeter: 31.41592653589793
Area: 78.53981633974483

Perimeter: 20.0
Area: 24.0

Perimeter: 18.84955592153876
Area: 28.274333882308138