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php多态实现uml

2026-02-15 12:06:35PHP

PHP多态实现与UML表示

多态是面向对象编程的核心概念之一，允许不同类的对象对同一消息做出响应。PHP通过继承和接口实现多态，UML类图可清晰描述这种关系。

通过继承实现多态

基类定义通用方法，子类重写该方法实现不同行为：

class Animal {
    public function makeSound() {
        return "Generic animal sound";
    }
}

class Dog extends Animal {
    public function makeSound() {
        return "Bark";
    }
}

class Cat extends Animal {
    public function makeSound() {
        return "Meow";
    }
}

function animalSound(Animal $animal) {
    echo $animal->makeSound();
}

$dog = new Dog();
$cat = new Cat();
animalSound($dog); // 输出: Bark
animalSound($cat); // 输出: Meow

UML表示：

基类Animal与子类Dog、Cat之间用带空心三角箭头的实线连接（泛化关系）
所有类包含makeSound()方法，子类方法前标注{redefined}

通过接口实现多态

接口定义契约，不同类实现相同接口但行为不同：

interface Payment {
    public function pay($amount);
}

class CreditCardPayment implements Payment {
    public function pay($amount) {
        echo "Paying $amount via Credit Card";
    }
}

class PayPalPayment implements Payment {
    public function pay($amount) {
        echo "Paying $amount via PayPal";
    }
}

function processPayment(Payment $payment, $amount) {
    $payment->pay($amount);
}

$creditCard = new CreditCardPayment();
$paypal = new PayPalPayment();
processPayment($creditCard, 100);
processPayment($paypal, 200);

UML表示：

接口Payment与实现类之间用带空心三角箭头的虚线连接（实现关系）
接口名称上方标注<<interface>>构造型
所有实现类必须包含接口定义的pay()方法

抽象类实现多态

抽象类结合继承和接口特点：

abstract class Shape {
    abstract public function calculateArea();
}

class Circle extends Shape {
    private $radius;

    public function __construct($radius) {
        $this->radius = $radius;
    }

    public function calculateArea() {
        return pi() * pow($this->radius, 2);
    }
}

class Square extends Shape {
    private $side;

    public function __construct($side) {
        $this->side = $side;
    }

    public function calculateArea() {
        return pow($this->side, 2);
    }
}

function printArea(Shape $shape) {
    echo "Area: " . $shape->calculateArea();
}

$circle = new Circle(5);
$square = new Square(4);
printArea($circle);
printArea($square);

UML表示：

php多态实现uml