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php如何实现多态

2026-02-13 20:14:02PHP

PHP 实现多态的方法

多态是面向对象编程的核心概念之一，PHP 主要通过继承和接口实现多态。以下是具体实现方式：

通过继承实现多态

利用父类和子类的继承关系，子类可以重写父类的方法，从而实现多态。

class Animal {
    public function makeSound() {
        echo "Animal sound";
    }
}

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

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

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

$dog = new Dog();
$cat = new Cat();

animalSound($dog); // 输出: Bark
animalSound($cat); // 输出: Meow

通过接口实现多态

接口定义了一组方法，任何实现该接口的类必须实现这些方法，从而实现多态。

interface Shape {
    public function calculateArea();
}

class Circle implements Shape {
    private $radius;

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

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

class Rectangle implements Shape {
    private $width;
    private $height;

    public function __construct($width, $height) {
        $this->width = $width;
        $this->height = $height;
    }

    public function calculateArea() {
        return $this->width * $this->height;
    }
}

function printArea(Shape $shape) {
    echo $shape->calculateArea();
}

$circle = new Circle(5);
$rectangle = new Rectangle(4, 6);

printArea($circle);    // 输出圆的面积
printArea($rectangle); // 输出矩形的面积

使用抽象类实现多态

抽象类可以定义部分实现，子类必须实现抽象方法，从而实现多态。

php如何实现多态

abstract class Vehicle {
    abstract public function drive();
}

class Car extends Vehicle {
    public function drive() {
        echo "Driving a car";
    }
}

class Bike extends Vehicle {
    public function drive() {
        echo "Riding a bike";
    }
}

function testDrive(Vehicle $vehicle) {
    $vehicle->drive();
}

$car = new Car();
$bike = new Bike();

testDrive($car);  // 输出: Driving a car
testDrive($bike); // 输出: Riding a bike