can servlet know servers' ip?

[Serdar BOZDAĞ]

hi, i call a servlet at http://www.asdfg.com/servlet/helloWorld....   this servlet need to know the ip of the server (http://www.asdfg.com) because there is a form in the servlet and in action this servlet is used again. so i need <FORM Action=" + ipOfTheServer + "/servlet/helloWorld">. could you help pls?   thanks in advance, serdar