关于include文件赋值的有关问题

include文件：
    $_CFG = array();
    $_CFG['DB_HOST'] = 'localhost';
    $_CFG['DB_USER'] = 'root';
    $_CFG['DB_PASWORD'] = 'liujianian';
    $_CFG['DB_NAME'] = 'commerceClub';

class conf{
	protected static $ins = null;
	protected  $data = array();
	final protected function _construct(){
		//一次性将配置文件读取进来
		include('./config.php');
		$this->data = $_CFG;
	}
	final protected function _clone(){
	
	}
	public static function getIns(){
		if(self::$ins instanceof self){
			return self::$ins;
		}else{
			self::$ins = new self();
			return self::$ins;
		}
	}
}
$conf = conf::getIns();
print_r($conf);