@startuml
' 设置样式
skinparam classAttributeIconSize 0
skinparam backgroundColor #FEFEFE
skinparam class {
    BackgroundColor #E1F5FE
    BorderColor #0288D1
    ArrowColor #0288D1
}

abstract class Shape {
    {abstract} + getArea(): double
}

class Circle {
    - radius: double
    + Circle(radius: double)
    + getArea(): double
}

class Rectangle {
    - width: double
    - height: double
    + Rectangle(width: double, height: double)
    + getArea(): double
}

class Triangle {
    - base: double
    - height: double
    + Triangle(base: double, height: double)
    + getArea(): double
}

class ShapeUtil {
    + {static} printArea(shape: Shape): void
}

' 继承关系
Shape <|-- Circle
Shape <|-- Rectangle
Shape <|-- Triangle

' 依赖关系
ShapeUtil ..> Shape : uses

@enduml