Autoloading Classes in PHP

How to autoload php class

1. What are Autoloading Classes?

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).

autoloading a class in php
autoloading a class in php

2. How to use Autoload Classes

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.

spl_autoload_register()

Example #1 Autoload example

This example attempts to load the classes MyClass1 and MyClass2 from the files MyClass1.php and MyClass2.php respectively.

Example #2 Autoload other example

This example attempts to load the interface ITest.

Example #3 Autoloading with exception handling for 5.3.0+

This example throws an exception and demonstrates the try/catch block.