我知道这已经晚了几年，但如果有人偶然发现这个问题，请尝试以下操作:

I know this is a few years late but if anyone stumbles across this question try the following:

InternetDomainName.from("subhost.example.co.uk").topPrivateDomain().name

以上将返回example.co.uk.

The above will return example.co.uk.