Two implementations of PHP auto loading

There are two ways to automatically load PHP.
The first scheme USES successive autoload, which is simpler and weaker.
One problem that hasn't been resolved is whether there is a problem with the file before include.

 
set_include_path('aa' . PATH_SEPARATOR . get_include_path()); 
function __autoload($className) 
{ 
//If you add this detection, because the file is not in the current directory, it will not detect the existence of the file,
//But include works
if (file_exists($className . '.php')) { 
　　include_once($className . '.php'); 
} else { 
exit('no file'); 
} 
} 
$a = new Acls(); 

The second option USES SPL to automatically load, and I'm going to talk about that here.
Spl_autoload_register ()
A simple example

 
set_include_path('aa' . PATH_SEPARATOR . get_include_path()); 
//function __autoload($className) 
//{ 
// if (file_exists($className . '.php')) { 
// include_once($className . '.php'); 
// } else { 
// exit('no file'); 
// } 
//} 
spl_autoload_register(); 
$a = new Acls(); 

Spl_autoload_register () automatically calls spl_autoload() to look for ".php" programs with lowercase file names in the path.
In the case of missing, you can also find by defining their own functions
Such as
The function loader1 ($class)
{
// write some load code yourself
}
The function loader2 ($class)
{
// when loader1() cannot be found, I will look for it
}
Spl_autoload_register (' loader1 ');
Spl_autoload_register (' loader2 ');
There could be more...
How does the MVC framework implement auto-loading
So let's set the path
'include' = > Array (' application/catalog/controllers', 'application/catalog/models'), $include = array (' application/controllers',' application/models', 'application/library');
Set_include_path (get_include_path().path_separator. Separator DE (PATH_SEPARATOR, $config['include']);
After getting the URL, parse out the controller and method.
Then set the auto load

 
class Loader 
{ 
 
public static function autoload($class) 
{ 
$path = ''; 
$path = str_replace('_', '/', $class) . '.php'; 
include_once($path); 
} 
} 
 
spl_autoload_register(array('Loader', 'autoload')); 

Routing, instantiating the controller, calling the method, and what you write is executed

 
 
public function route() 
{ 
if (class_exists($this->getController())) { 
$rc = new ReflectionClass($this->getController()); 
if ($rc->hasMethod($this->getAction())) { 
$controller = $rc->newInstance(); 
$method = $rc->getMethod($this->getAction()); 
$method->invoke($controller); 
} else 
throw new Exception('no action'); 
} else 
throw new Exception('no controller'); 
} 

The initial auto-load is complete