问自动装载课程。自动加载功能不起作用

EN

Fatal error: Class 'User' not found in C:\Program Files\xampp\htdocs\MVCApp\index.php on line 35 

<?php

        //define('APPLICATION_PATH', realpath('../'));//C:\Program Files\xampp\htdocs
         define('APPLICATION_PATH', realpath('../'));//C:\Program Files\xampp\htdocs\MVCApp

        echo APPLICATION_PATH;

        $paths=array(
            APPLICATION_PATH,
            APPLICATION_PATH.'/com',
            get_include_path(),


        );
        set_include_path(implode(PATH_SEPARATOR, $paths));

       // echo get_include_path();//C:\Program Files\xampp\php\PEAR

        function _autoload($className)
       {
          require_once $className.'.php';
          return;
       }


          $user=new User();

          echo $user->getName();


        ?>


        C:\Program Files\xampp\htdocs\MVCApp\com\User.php file

        <?php

<?php

class User {

    public function getName()
    {
       return 'Hello Sam';
    }
}