PHP automatic loading of two functions __autoload and __sql_autoload_register

First, __autoload

This is an auto-load function, which is triggered when we instantiate an undefined class in PHP5. Look at the following example:

printit.class.php   //File <?php  class PrintIt {   function doprint () {  echo ' Hello World ';}}? >  index.php     //File <?phpfunction __autoload ($class) {$file = $class. '. class.php ';   if (Is_file ($file)) {    require_once ($file);}   }  $obj = new PrintIt (); $obj->doprint ();? >

Second, Spl_autoload_register ()

1. It tells PHP to execute the specified class when it encounters a class that is not defined;

<?phpfunction Loadprint ($class) {$file = $class. '. class.php ';   if (Is_file ($file)) {    require_once ($file);}   }  Spl_autoload_register (' Loadprint ');  $obj = new PrintIt (); $obj->doprint ();? >

2, Spl_autoload_register () call static method

<?phpclass Test {public static function Loadprint ($class) {  $file = $class. '. class.php ';    if (Is_file ($file)) {     require_once ($file);}}  }  Spl_autoload_register (  Array (' Test ', ' Loadprint ')  );//Another notation: Spl_autoload_register (  "test:: Loadprint "  );  $obj = new PrintIt (); $obj->doprint ();? >

PHP automatic loading of two functions __autoload and __sql_autoload_register