mvc. redirect controller to controller with request object

hi
redirectView only mak url redirection.
if we use render method of redirectView and add request parameter to Map, we send request parameters to other controller, so other controller can take request parameter as follow
String username=request.getParameter("username");
but our controller need to use attributes of request for object values,

User user = (User) request.getAttribute("user");

in this case we sent request object controller to other controller
how can I do?