Strange Question---php-include_once.

1. It's a wonderful question.

Nginx under Project/www/data

Do_boss_apis.com,do_apis.com

The structure of this two project directory is the same

2. Under Do_boss_apis.com

Index.php:include_once ' core/system/application.class.php '; is the file under do_apis.com introduced? Why????

Index.php:include_once './core/system/application.class.php '; Introduced in the current directory: File OK.

3. It's going to break down, go home and talk tomorrow.

Strange Question---php-include_once.