@PreAuthorize("@SS.hasPermi()")

This annotation is used in Spring Security to specify that the method being annotated should only be executed if the current user has permission to do so. The permission check is performed using the SS (Spring Security) object, which has a method called hasPermi() that checks if the current user has the required permission. The permission itself is typically defined in a custom PermissionEvaluator implemented in the application.

In other words, this annotation helps to ensure that only authorized users can access certain functionality within the application.