PHP Automatic loading

__autoload () auto-load function, in PHP5, when we instantiate an undefined class, this function is triggered. The static call is not valid. It is deprecated.

Spl_autoload_register () http://php.net/manual/zh/function.spl-autoload-register.php

Supports automatic loading at static calls, and can load multiple processing functions or methods.

When using namespaces, you need to be aware of the relationship between the namespace name and the file path, or you may not find a handler function or you cannot load the class.

PHP Automatic loading