PHP:AutoLoader是否可以在单个php文件中加载多个类? [英] PHP: Is AutoLoader able to load multiple class in a single php file？

问题描述

自动加载类的引用:

许多编写面向对象应用程序的开发人员创建了一个PHP每个类定义的源文件.最大的烦恼之一是必须在开始时写一长串所需的清单每个脚本(每个类一个).

Many developers writing object-oriented applications create one PHP source file per class definition. One of the biggest annoyances is having to write a long list of needed includes at the beginning of each script (one for each class).

在PHP 5中，这不再是必需的.spl_autoload_register()函数注册任意数量的自动加载器，从而启用类和如果当前没有自动加载的接口定义.通过注册自动加载器，PHP得到了最后的机会在出现错误之前加载类或接口.

In PHP 5, this is no longer necessary. The spl_autoload_register() function registers any number of autoloaders, enabling for classes and interfaces to be automatically loaded if they are currently not defined. By registering autoloaders, PHP is given a last chance to load the class or interface before it fails with an error.

这里是一个问题，如果单个php文件中有多个类，该代码适合自动加载吗?还是我必须使用 require filepath 语句?

Here comes the question, what if there are multiple classes in a single php file, is it suitable for autoload usage? or do I have to use require filepath statement?

例如，我在Protobuf \ Client.php下有一个协议文件:

For example, I have a protocol file under Protobuf\Client.php:

<?php

namespace Protobuf;
class A {
...
}
class B {
...
}

推荐答案

您必须具有一些复杂的功能，才能从名为 Client.php 的文件中自动加载这些类.这个想法是将您的 namespace \ classname 转换为 directory \ filename.php

You would have to have some complex function to autoload those classes from the file named Client.php. The idea is to translate your namespace\classname into a directory\filename.php

在这种情况下，您需要将文件命名为 A.php ，然后在调用 new Protobuf \ A()时会找到它.否则，您将不得不创建一个过于复杂的自动加载器.

In this instance you would need to name your file A.php then when you call new Protobuf\A() it will find it. Otherwise you will have to create an overly-complex autoloader.

假设您创建了自动加载器，以便找到 A 类，然后可以在同一文件上具有 B ，但前提是您已经自动加载了 A ，否则您必须做一些算法才能知道 A 和 B 在同一页面上.

Let's say you do create the autoloader so it finds the A class, then you can have B on the same file, but only if you have already autoloaded A otherwise you have to make some algorythm to know that A and B are on the same page.

我将执行上述模式或 Magento 之类的应用所采用的模式，该模式通过替换下划线将类名转换为目录路径:

I would do the above pattern or the pattern adopted by apps like Magento that turn class names into directory paths by replacing underscores:

$class = new Core_Classes_MyClass_Client();

您的自动加载器将替换下划线并加载:

Your autoloader would replace the underscores and will load:

Core/Classes/MyClass/Client.php //or similar scheme

这对我来说是一种简单的方法，但是我更喜欢使用名称空间和类.上面的方法目前并不受欢迎，从命名的角度来看，很容易混淆，因为很多类可能位于同一文件夹中，或者实际上嵌套在子文件夹中.您可能会为类获得一些很长的命名.

This to me is an easy way to do it, but I prefer using namespace and class. The above method is not in favor at the moment and from a naming standpoint, very easy to get mixed up since a lot of classes may be in the same folder or nested really deep into sub folders. You could get some really long naming for classes.

这篇关于PHP:AutoLoader是否可以在单个php文件中加载多个类?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！