__autoload() - php 类对象函数
__autoload()
(PHP 5, PHP 7)
尝试加载未定义的类
WarningThis feature has beenDEPRECATEDas of PHP 7.2.0. Relying on this featureis highly discouraged.
说明
__autoload(string $class): void你可以通过定义这个函数来启用类的自动加载。
参数
$class待加载的类名。
返回值
没有返回值。
参见
spl_autoload_register()
注册给定的函数作为 __autoload 的实现
It is highly recommended not to use the __autoload() function any more. Now the spl_autoload_register() function is what you should consider.Sorry for the mistake in line 6 of my previous note. And below is the corrected PHP code.
Even I have never been using this function, just a simple example in order to explain it; ./myClass.php *** At this line, our "./myClass.php" will be included! This is the magic that we're wondering... And you get this result "myClass init'ed successfuly!!!". So, if you call a class that named as myClass then a file will be included myClass.php if it exists (if not you get an include error normally). If you call Foo, Foo.php will be included, and so on... And you don't need some code like this anymore; Your class files will be included "automatically" when you call (init) them without these functions: "include, include_once, require, require_once".
qeremy, your code is incorrect. should be:
If you can keep file name and class name as same, it will be good programming practice. It helps to __autoload function to load file without checking any condition. function __autoload($class){ require_once( $class.".php"); }
keyboardSmasher You may or may not be right as the file name doesn't necessarily have to reflect a class name it contains (but it's usually considered a good practice). It isn't always a straightforward mapping (look at some PHP frameworks and autoload implementations). File myBar.php may contain the class: class Bar { } or it even contain the class: class Foo { } Best regards
Simple autoload : function __autoload($class_name){ require 'class/' . $class_name . '.php'; }
You should use include() or require() inside __autoload() instead of include_once() or require_once(). If you reach __autoload(), then you know the file with the class definition has not been loaded yet. include() and require() are more efficient than include_once() and require_once().
In PHP 7.2, this code will trigger a " Deprecated: __autoload() is deprecated, use spl_autoload_register() instead in path\to\file.php on line *" error although the spl_autoload_register function really really exists.
Guys, this document ( i mean __autoload() ) not mentioned one special situation: if you both use __autoload() and spl_autoload_register(), the __autoload() function will never to be called. Although spl_autoload_register() documentation explained why, i decide to wrote this in case some one get confused and waste all day to figure out why. Here is some code to verify above:
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