Home Backend Development PHP Tutorial PHP autoload implements automatic loading of classes_PHP tutorial

PHP autoload implements automatic loading of classes_PHP tutorial

Jul 13, 2016 am 10:44 AM
autoload php use load Can accomplish mechanism program kind automatic

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 Copy code

$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 Copy code
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...
Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)
1 months ago By 尊渡假赌尊渡假赌尊渡假赌
R.E.P.O. Best Graphic Settings
1 months ago By 尊渡假赌尊渡假赌尊渡假赌
Will R.E.P.O. Have Crossplay?
1 months ago By 尊渡假赌尊渡假赌尊渡假赌

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

PHP 8.4 Installation and Upgrade guide for Ubuntu and Debian PHP 8.4 Installation and Upgrade guide for Ubuntu and Debian Dec 24, 2024 pm 04:42 PM

PHP 8.4 brings several new features, security improvements, and performance improvements with healthy amounts of feature deprecations and removals. This guide explains how to install PHP 8.4 or upgrade to PHP 8.4 on Ubuntu, Debian, or their derivati

How To Set Up Visual Studio Code (VS Code) for PHP Development How To Set Up Visual Studio Code (VS Code) for PHP Development Dec 20, 2024 am 11:31 AM

Visual Studio Code, also known as VS Code, is a free source code editor — or integrated development environment (IDE) — available for all major operating systems. With a large collection of extensions for many programming languages, VS Code can be c

7 PHP Functions I Regret I Didn't Know Before 7 PHP Functions I Regret I Didn't Know Before Nov 13, 2024 am 09:42 AM

If you are an experienced PHP developer, you might have the feeling that you’ve been there and done that already.You have developed a significant number of applications, debugged millions of lines of code, and tweaked a bunch of scripts to achieve op

How do you parse and process HTML/XML in PHP? How do you parse and process HTML/XML in PHP? Feb 07, 2025 am 11:57 AM

This tutorial demonstrates how to efficiently process XML documents using PHP. XML (eXtensible Markup Language) is a versatile text-based markup language designed for both human readability and machine parsing. It's commonly used for data storage an

Explain JSON Web Tokens (JWT) and their use case in PHP APIs. Explain JSON Web Tokens (JWT) and their use case in PHP APIs. Apr 05, 2025 am 12:04 AM

JWT is an open standard based on JSON, used to securely transmit information between parties, mainly for identity authentication and information exchange. 1. JWT consists of three parts: Header, Payload and Signature. 2. The working principle of JWT includes three steps: generating JWT, verifying JWT and parsing Payload. 3. When using JWT for authentication in PHP, JWT can be generated and verified, and user role and permission information can be included in advanced usage. 4. Common errors include signature verification failure, token expiration, and payload oversized. Debugging skills include using debugging tools and logging. 5. Performance optimization and best practices include using appropriate signature algorithms, setting validity periods reasonably,

PHP Program to Count Vowels in a String PHP Program to Count Vowels in a String Feb 07, 2025 pm 12:12 PM

A string is a sequence of characters, including letters, numbers, and symbols. This tutorial will learn how to calculate the number of vowels in a given string in PHP using different methods. The vowels in English are a, e, i, o, u, and they can be uppercase or lowercase. What is a vowel? Vowels are alphabetic characters that represent a specific pronunciation. There are five vowels in English, including uppercase and lowercase: a, e, i, o, u Example 1 Input: String = "Tutorialspoint" Output: 6 explain The vowels in the string "Tutorialspoint" are u, o, i, a, o, i. There are 6 yuan in total

Explain late static binding in PHP (static::). Explain late static binding in PHP (static::). Apr 03, 2025 am 12:04 AM

Static binding (static::) implements late static binding (LSB) in PHP, allowing calling classes to be referenced in static contexts rather than defining classes. 1) The parsing process is performed at runtime, 2) Look up the call class in the inheritance relationship, 3) It may bring performance overhead.

What are PHP magic methods (__construct, __destruct, __call, __get, __set, etc.) and provide use cases? What are PHP magic methods (__construct, __destruct, __call, __get, __set, etc.) and provide use cases? Apr 03, 2025 am 12:03 AM

What are the magic methods of PHP? PHP's magic methods include: 1.\_\_construct, used to initialize objects; 2.\_\_destruct, used to clean up resources; 3.\_\_call, handle non-existent method calls; 4.\_\_get, implement dynamic attribute access; 5.\_\_set, implement dynamic attribute settings. These methods are automatically called in certain situations, improving code flexibility and efficiency.

See all articles