Detecting host name in java

Question

Is it possible to detect the hostname used in java (even through a cname)?

I am looking for something similar to this: http://api.drupal.org/api/function/conf_path/6

In that code, drupal checks to see what domain name is accessing it in order to load the correct configuration (multi-site). If the domain doesn't match any configurations, it just goes to the default configuration.

Answer 1

Have a look at InetAddress.getLocalHost(), followed by calling getHostName() on the returned value, which does exactly this.

Be aware that not all machines will be able to resolve a network interface which can be used for the local hostname, and that multi-homed machines run into some additional complications too. Thus if you're developing software that will need to work in a variety of situations, consider the edge cases properly as well as the happy path.

Answer 2

Of course doing this causes a reverse DNS lookup for each getHostName() call.
It is a performance penalty on busy sites.
I would recommend doing getHostAddress() and later on looking up the host names.