Process URL in Java

Use Regex pattern to extract URL in String:

           String url_pattern = "\\b(https?|ftp|file|ldap)://"  
       + "[-A-Za-z0-9+&@#/%?=~_|!:,.;]"  
       + "*[-A-Za-z0-9+&@#/%=~_|]";  
           Pattern p = Pattern.compile(url_pattern, Pattern.CASE_INSENSITIVE);  
           Matcher m = p.matcher(post.getContent());  
           // Find all url and do your logic  
           while (m.find()) {  
           }  

Expand shorten URL: 
http://www.srccodes.com/p/article/37/expand-shortened-link-using-java

URL Validator:
https://commons.apache.org/proper/commons-validator/