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The ClassLoader Component
The ClassLoader component provides tools to autoload your classes and cache their locations for performance.
Usage
Whenever you reference a class that has not been required or included yet, PHP uses the autoloading mechanism to delegate the loading of a file defining the class. Symfony provides three autoloaders, which are able to load your classes:
- The PSR-0 Class Loader: loads classes that follow the PSR-0 class naming standard;
- The PSR-4 Class Loader: loads classes that follow the `PSR-4` class naming standard;
- MapClassLoader: loads classes using a static map from class name to file path.
Additionally, the Symfony ClassLoader component ships with a wrapper class which makes it possible to cache the results of a class loader.
When using the Debug component, you can also use a special DebugClassLoader that eases debugging by throwing more helpful exceptions when a class could not be found by a class loader.
Installation
You can install the component in 2 different ways:
- Install it via Composer (
symfony/class-loaderon Packagist); - Use the official Git repository (https://github.com/symfony/ClassLoader).
Then, require the vendor/autoload.php file to enable the autoloading mechanism
provided by Composer. Otherwise, your application won't be able to find the classes
of this Symfony component.