public static function get($name, $default = NULL)
 {
     $value = NULL;
     if (array_key_exists($name, Y::getParams())) {
         $value = Y::getParams($name);
     } else {
         $params = $_GET;
         if (array_key_exists($name, $params)) {
             $value = $params[$name];
         }
     }
     if (!self::validate('get_' . $name, $value) || is_null($value)) {
         $value = $default;
     }
     return $value;
 }
 public function __destruct()
 {
     if (Y::getParams('debug') && Y::getParams('debug') == 'safe') {
         //开启xhprof
         Debug::disable();
     }
 }