1)设计其抽象子类二维图形（TwoDGraph），添加计算面积calArea()和周长calPerimeter()两个抽象方法； 2)从TwoDGraph类派生出圆形Circle，增加圆心centerPoint和半径radius属性，增加构造方法； 3)在Circle中重写calArea、calPerimeter和toString()方法 4)从TwoDGraph类派生出长方形Rectangle，增加左上角坐标leftPoint、长length和宽width属性，增加构造方法； 5)在Rectangle中重写calArea、calPerimeter和toString()方法 6)在Rectangle新增输出4个顶点坐标方法outputPoints() 7)在main方法中，测试Circle和Rectangle类中的方法。

好的，我明白了，让我们逐步来完成这些要求。

首先是抽象类TwoDGraph的设计：

public abstract class TwoDGraph {
    public abstract double calArea();
    public abstract double calPerimeter();
}

接下来是圆形类Circle的设计：

public class Circle extends TwoDGraph {
    private Point centerPoint;
    private double radius;

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

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

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

    @Override
    public String toString() {
        return "Circle: center point = " + centerPoint.toString() + ", radius = " + radius;
    }
}

注意这里我们用到了一个Point类，表示一个二维平面上的点：

public class Point {
    private double x;
    private double y;

    public Point(double x, double y) {
        this.x = x;
        this.y = y;
    }

    public double getX() {
        return x;
    }

    public double getY() {
        return y;
    }

    @Override
    public String toString() {
        return "(" + x + ", " + y + ")";
    }
}

接下来是长方形类Rectangle的设计：

public class Rectangle extends TwoDGraph {
    private Point leftPoint;
    private double length;
    private double width;

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

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

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

    @Override
    public String toString() {
        return "Rectangle: left point = " + leftPoint.toString() + ", length = " + length + ", width = " + width;
    }

    public void outputPoints() {
        Point rightPoint = new Point(leftPoint.getX() + length, leftPoint.getY());
        Point bottomPoint = new Point(leftPoint.getX(), leftPoint.getY() - width);
        Point rightBottomPoint = new Point(leftPoint.getX() + length, leftPoint.getY() - width);
        System.out.println("The four points of the rectangle are: " + leftPoint.toString() + ", " +
                rightPoint.toString() + ", " + bottomPoint.toString() + ", " + rightBottomPoint.toString());
    }
}

最后，在main方法中进行测试：

public static void main(String[] args) {
    Circle circle = new Circle(new Point(0, 0), 5);
    System.out.println(circle.toString());
    System.out.println("Area of the circle: " + circle.calArea());
    System.out.println("Perimeter of the circle: " + circle.calPerimeter());

    Rectangle rectangle = new Rectangle(new Point(0, 0), 3, 4);
    System.out.println(rectangle.toString());
    System.out.println("Area of the rectangle: " + rectangle.calArea());
    System.out.println("Perimeter of the rectangle: " + rectangle.calPerimeter());
    rectangle.outputPoints();
}

输出结果如下：

Circle: center point = (0.0, 0.0), radius = 5.0
Area of the circle: 78.53981633974483
Perimeter of the circle: 31.41592653589793
Rectangle: left point = (0.0, 0.0), length = 3.0, width = 4.0
Area of the rectangle: 12.0
Perimeter of the rectangle: 14.0
The four points of the rectangle are: (0.0, 0.0), (3.0, 0.0), (0.0, -4.0), (3.0, -4.0)