为什么我不能在 PHP 中重载构造函数?

2021-12-30 00:00:00 oop constructor overloading php

我已经放弃了在 PHP 中重载构造函数的所有希望，所以我真正想知道的是为什么.

I have abandoned all hope of ever being able to overload my constructors in PHP, so what I'd really like to know is why.

有什么原因吗?它是否会创建本质上不好的代码?是被广泛接受的语言设计不允许，还是其他语言比 PHP 更好?

Is there even a reason for it? Does it create inherently bad code? Is it widely accepted language design to not allow it, or are other languages nicer than PHP?

推荐答案

您不能在 PHP 中重载任何方法.如果您希望能够在传递多个不同参数组合的同时实例化 PHP 对象，请使用带有私有构造函数的工厂模式.

You can't overload ANY method in PHP. If you want to be able to instantiate a PHP object while passing several different combinations of parameters, use the factory pattern with a private constructor.

例如:

public MyClass {
    private function __construct() {
    ...
    }

    public static function makeNewWithParameterA($paramA) {
        $obj = new MyClass(); 
        // other initialization
        return $obj;
    }

    public static function makeNewWithParametersBandC($paramB, $paramC) {
        $obj = new MyClass(); 
        // other initialization
        return $obj;
    }
}

$myObject = MyClass::makeNewWithParameterA("foo");
$anotherObject = MyClass::makeNewWithParametersBandC("bar", 3);

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