guava com.google.common.net.InetAddresses

Question

I'd like to check in java if an IP address (IPv4, IPv6) is valid.

Google's guava library looks to me like a viable option. Its isInetAddress(String ipString) method works just fine for IPv4 addresses. However for IPv6 addresses I'd have to use the isIsatapAddress(Inet6Address ip) method.

The problem is that I want to use the args from the void main(String []args) to capture user's input and since the method requires a Inet6Address object I'm not sure how to do that.

Answer 1

InetAddresses.isInetAddress(String) should work for both IPv4 and IPv6 addresses.

If you have also want to accept something like 2607:f0d0:1002:51::4/64 you could strip the netmask off with a little indexOf and substring, I don't think there's a method for that yet in Guava:

static boolean isInetAddressOrBlock(String address) {
  int slash = address.lastIndexOf('/');
  if (slash != -1) {
    address = address.substring(0, slash);
  }
  return InetAddresses.isInetAddress(address);
}

If you considered using sun.net.util.IPAddressUtil, don't -- sun.* packages are implementation details of your JRE, not meant to be used and not available on all JREs.