Detailed explanation of the usage of php function spl_autoload_register

class A{
　public function __construct(){
　　echo 'Got it.';
　}
}

Then, there is an index.php that needs to be used To this class A, the conventional writing method is:

require('A.php');
$a = new A();

Problem : If index.php needs to contain not just class A, but many classes, you must write many lines of require statements.

In php5, the __autoload function is automatically called when trying to use a class that has not been defined, so you can let php automatically load the class by writing the __autoload function.

The above example can be modified as:

function __autoload($class) {
　 $file = $class . '.php';
　if (is_file($file)) {
　　require_once($file ; Define the rules for loading classes with __autoload.



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Continue to modify the above example:

function loader($class) {

　$file = $class . '.php';

　if (is_file($file)) {

　　require_once($file

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php does not call __autoload when looking for a class but calls the self-defined function loader.

The following writing methods are also possible, for example:

class Loader {

　public static function loadClass($class) {

　　$file = $class . '.php';

　　if (is_file($file)) {

　　　 require_once($file);

spl_autoload_register(array('Loader', 'loadClass'));
$a = new A();



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