Validating URI, below redirect. Web App : Servlets Java

I have URL entered by users.

User can enter URI. [relat开发者_如何学Cive URI]

How can I validate that relative URI ?

EX: For absolute URI https://stackoverflow.com/questions/ask.

User can enter "questions/ask".

Is there any ways read web.xml to validate uri.[Java web app]

• if you can verify whether the address actually exists, you can use:

  HttpURLConnection connection = 
       (HttpURLConnection) new URL(host + relativePart).openConnection();
  
  
  int status = connection.getResponseCode(); 
  

and see whether status 200 will be returned.

• if you want to check if the URI is well formed according to RFC 2396 - new URI(uri)