@WebServlet("/textfileAPI")
public class Servlet extends HttpServlet {

    static String q;
    static int limit;
    static  int lenght;
        Filter filter;
        @Override
        protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

            req.setAttribute("q",q);
            req.setAttribute("limit",limit);
            req.setAttribute("length",lenght);
            filter.setQ(q);
            filter.setLimit(limit);
            filter.setLength(lenght);
            PrintWriter writer = resp.getWriter();
            writer.println("<p>"+filter.filtration(filter.getQ(),filter.getLimit(),filter.getLength())+"<p>");
        }
}