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php实现多态

2026-02-13 15:13:33PHP

PHP 实现多态的方法

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作出不同的响应。PHP 通过继承、接口和抽象类实现多态。

通过继承实现多态

子类可以重写父类的方法，实现不同的行为。调用时根据对象类型决定执行哪个方法。

php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";
    }
}

$animals = [new Animal(), new Dog(), new Cat()];
foreach ($animals as $animal) {
    $animal->makeSound();
}

通过接口实现多态

接口定义一组方法签名，不同类实现相同接口但提供不同实现。

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 Square implements Shape {
    private $side;

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

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

$shapes = [new Circle(5), new Square(4)];
foreach ($shapes as $shape) {
    echo $shape->calculateArea();
}

通过抽象类实现多态

抽象类可以包含抽象方法和具体方法，子类必须实现抽象方法。

php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";
    }
}

$vehicles = [new Car(), new Bike()];
foreach ($vehicles as $vehicle) {
    $vehicle->drive();
}

类型提示与多态

方法参数使用父类或接口类型提示，可以接受任何子类或实现类的实例。

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

makeSound(new Dog());
makeSound(new Cat());

动态方法调用

PHP 支持动态调用方法，进一步增强多态性。

class Printer {
    public function printDocument() {
        echo "Printing document";
    }
}

class Fax {
    public function sendFax() {
        echo "Sending fax";
    }
}

function execute($device, $method) {
    $device->$method();
}

execute(new Printer(), 'printDocument');
execute(new Fax(), 'sendFax');