Direcionar URL após o login - Falta um detalhe

package loginControle;
import java.io.IOException;   
import javax.servlet.Filter;   
import javax.servlet.FilterChain;   
import javax.servlet.FilterConfig;   
import javax.servlet.ServletException;   
import javax.servlet.ServletRequest;   
import javax.servlet.ServletResponse;   
import javax.servlet.http.HttpServletRequest;   
import javax.servlet.http.HttpServletResponse;   
import javax.servlet.http.HttpSession;   
  
  
public class Validator implements Filter{   
      
   public void destroy() {   
   }   
  
   public void doFilter(ServletRequest request, ServletResponse response, FilterChain filter) throws IOException, ServletException {   
      HttpServletRequest req = (HttpServletRequest) request;   
      HttpServletResponse res = (HttpServletResponse) response;   
         
      HttpSession session = req.getSession();   
      String user = (String) session.getAttribute("login_portal");   
      if(user!=null && user.trim().length()>0){   
         return;   
      }   
      res.sendRedirect("../index.jsp");   
   }   
  
   public void init(FilterConfig arg0) throws ServletException {   
   }   
}  

<filter>
    <display-name>Validator</display-name>
    <filter-name>Validator</filter-name>
    <filter-class>loginControle.Validator</filter-class>
  </filter>
  <filter-mapping>
    <filter-name>Validator</filter-name>
    <url-pattern>/cqa/*</url-pattern>
  </filter-mapping>