code: public static String getQueryParameter( URI uri, String name )
      {
          Map<String, String> params = parseQueryParameters( uri.getRawQuery() );
          return params.get( name );
      }
docs: Retrieves a query param in a URL according to a key.
  
  If several parameters are to be retrieved from the same URI, better use
  <code>parseQueryString( uri.getRawQuery() )</code>.
  
  @param uri
  @param name
  @return parameter value (if found) ; null if not found or no = after name.