classDiagram
    class Graphic {
        <<interface>>
        + double area()
        + double perimeter()
    }

    class Circle {
        - double radius
        + Circle(double radius)
        + double area()
        + double perimeter()
        + double getRadius()
    }

    class Rectangle {
        - double width
        - double height
        + Rectangle(double width, double height)
        + double area()
        + double perimeter()
        + double getWidth()
        + double getHeight()
    }

    class Test {
        + main(String[] args)
    }

    Graphic <|.. Circle : 实现
    Graphic <|.. Rectangle : 实现
    Test --> Circle : 创建与使用
    Test --> Rectangle : 创建与使用