HttpServletRequest httpRequest = (HttpServletRequest) request;
httpRequest.getSession().setAttribute("login", account);
chain.doFilter(httpRequest, httpResponse);

public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String userAccount = request.getParameter("userAccount");
        respons.setContentType("text/html; charset=UTF-8");
        try
        {
            out = respons.getWriter();
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
        //注销session
        HttpSession session = request.getSession();

            }

HttpServletRequest httpRequest = (HttpServletRequest)request;
Object login = httpRequest.getSession().getAttribute("login");