Anyone have a good (preferably tested) regex for accepting only a valid DNS hostname, IPv4 or IPv6 address?
I understand that you may be forced to use a regex. However, if possible it is better to avoid using regexes for this task and use a Java library class to do the validation instead.
If you want to do validation and DNS lookup together, then InetAddress.getByName(String)
is a good choice. This will cope with DNS, IPv4 and IPv6 in one go, and it returns you a neatly wrapped InetAddress
instance that contains both the DNS name (if provided) and the IPv4 or IPv6 address.
If you just want to do a syntactic validation, then Apache commons has a couple of classes that should do the job: DomainValidator
and InetAddressValidator
.