PHP autoload implements automatic loading of classes

PHP autoload implements automatic loading of classes_PHP tutorial

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Release： 2016-07-13 10:44:53

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The autoload mechanism makes it possible for PHP programs to automatically include class files only when classes are used, instead of including all class files from the beginning. This mechanism is also called lazy loading.

The following is an example of using the autoload mechanism to load the Person class:

Plan it yourself and use it in conjunction with set_include_path and get_include_path to make the automatic loading class more complete. The code will be faster (imitating magento):

The code is as follows

代码如下	复制代码
/* autoload.php */ function __autoload($classname) { require_once ($classname . “class.php”); } $person = new Person(”Altair”, 6); var_dump ($person); ?>

Copy code

/* autoload.php */
function __autoload($classname) {
require_once ($classname . “class.php”);
}
$person = new Person("Altair", 6);
var_dump ($person);
?>

代码如下

复制代码

$paths[] = BP . DS . ‘app’ . DS . ‘local’;
$paths[] = BP . DS . ‘app’ . DS . ‘base’;
$paths[] = BP . DS . ‘lib’;

$appPath = implode(PS, $paths);
set_include_path($appPath . PS . get_include_path());

Implementation of PHP’s autoload mechanism

代码如下

复制代码

class Autoload {

/**
* 自身对象
*
*/
protected static $_instance = null;

public function __construct() {

}

/*
* 实例化自身
*
*/

public static function instance() {
if (null == self::$_instance) {
self::$_instance = new self();
}

return self::$_instance;
}

/**
*
* 注册自动加载函数
*/
public static function register() {
spl_autoload_register(array(self::instance(), ‘autoload’));
}

/*
*
* 自动加载类
*/

public function autoload($class) {
if (!is_string($class)) {
return;
}

$classFile = str_replace(‘ ‘, DS, ucwords(str_replace(‘_’, ‘ ‘, $class)));
$classFile .= ‘.php’;
return include $classFile;
}

}

To implement automatic loading of classes in PHP, we need to talk about a magic method, __autoload(); this is the automatic loading class method added by PHP5. As long as this function is defined, if PHP runs and the class cannot be found, it will search according to the rules of __autoload.

The code is as follows

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$paths[] = BP . DS . ‘app’ . DS . ‘local’;
$paths[] = BP . DS . ‘app’ . DS . ‘base’;
$paths[] = BP . DS . ‘lib’; $appPath = implode(PS, $paths);
set_include_path($appPath . PS . get_include_path()); In this way, you can add a default class loading environment for PHP. Here, you just add the path to the PHP environment. If you want to continue adding rules, you can define the __autoload function. However, I use it here for objects, so I changed it. One method: spl_autoload_register method. The following is a set I made based on the rules of magento. In fact, it is similar to magento.

The code is as follows

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class Autoload {

/**
* Self object
*
*/
protected static $_instance = null; public function __construct() { } /*
* Instantiate itself
*
*/ public static function instance() {
if (null == self::$_instance) {
self::$_instance = new self();
} return self::$_instance;
} /**
*
* Register automatic loading function
*/
public static function register() {
spl_autoload_register(array(self::instance(), ‘autoload’));
} /*
*
* Automatically load classes
*/ public function autoload($class) {
if (!is_string($class)) {
return;
} $classFile = str_replace(‘ ‘, DS, ucwords(str_replace(‘_’, ‘ ‘, $class)));
$classFile .= ‘.php’;
return include $classFile;
} } http://www.bkjia.com/PHPjc/633080.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/633080.htmlTechArticleThe autoload mechanism makes it possible for PHP programs to automatically include class files only when they are used, instead of including them from the beginning. All class files are included. This mechanism is also called lazy loading. Next...