Session filter [RESOLVIDO]

"servlet"

package servlet;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 *
 * @author CPD04
 */
public class ServletAutentica extends HttpServlet {

    /** 
     * Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        try {
            String usuario = request.getParameter("usuario");
            String senha = request.getParameter("senha");
            
            if(usuario.equals("ADMIN") && senha.equals("123")){
                
                HttpSession session  = request.getSession();
                session.setAttribute("usuario",usuario);
                System.out.println(session.getAttribute(usuario));
                response.sendRedirect("pgRestrito/principal.jsp");
            }else{
                response.sendRedirect("index.jsp");
            }

        } finally {            
            out.close();
        }
    }

    

"filter"

public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain)
            throws IOException, ServletException {
        
        HttpServletRequest rq = (HttpServletRequest)request;
        HttpServletResponse rs = (HttpServletResponse)response;
        
        
        HttpSession session = rq.getSession();
               
        if(session.getAttribute("usuario") != null){
            chain.doFilter(request, response);
        }else{
            rs.sendRedirect("../index.jsp");
        }
    }