fetching top level domain from URL.

[Minhaj Mehmood]

Hi All,

I'm using java.net.URI#getHost() method to extract the top level domain from an URL.
but this method is failed to extract the TLD of such URLs "http://www.schönesdresden.de/resources/internet.2jpg.jpg" It's failed due to umlaut "ö" in it.

Please Advise.

[Sunny Bhandari]

Not sure about java.net package but you can also do that job by String operations.

[Ralph Cook]

It would be very helpful if you would post some code and quote an error message, etc. What you say may be accurate, but it's difficult to help without knowing in more detail what is happening.

rc

[Minhaj Mehmood]

Following is my code:

import java.net.*;

class UrlTest{
	public static void main(String... args) throws URISyntaxException{

		String url = "http://www.schönesdresden.de/resources/internet.2jpg";
		URI uri = new URI(url);
		String host = uri.getHost();
		System.out.println(host); //giving null here, remove 'ö' from url then check.
	}
}

[Rob Spoor]

You can try to use java.net.URL instead of java.net.URI. That will not make getHost() return null. It still can't handle the ö though. For some reason it gets translated from ö (int value 148) to ÷ (int value 246). This conversion already happens in the URL constructor. I've also tried the URL(String, String, String) constructor but I get the same result. The code for URL shows me that the HTTP specific URLStreamHandler is doing this.

[Ralph Cook]

Actually, I should have known the answer from the original description -- RFC 1738 specifies the characters that are allowed in URLs, and it doesn't include anything with umlauts.

"...Only alphanumerics [0-9a-zA-Z], the special characters "$-_.+!*'()," [not including the quotes - ed], and reserved characters used for their reserved purposes may be used unencoded within a URL."

So it isn't working because it isn't supposed to work. You need to use a URL encoder to encode the umlauted o.

rc

[Paul Clapham]

Wasn't there some change recently in which you could have domain names in all kinds of character sets? (Goes off and searches the web...) Yes, there was. Here is an example of somebody registering such domains. However I don't know the details of how it works. There must have been an RFC for it.

(Looks back at results of web search...) And of course there's already a Wikipedia page about it: Internationalized domain name.

[Minhaj Mehmood]

I think the answer has been found check this: http://weblogs.java.net/blog/2007/03/29/international-domain-names

[Campbell Ritchie]

Minhaj Mehmood wrote:I think the answer has been found . . .

Well done finding that solution