cookie

Cookie userIdCookie = new Cookie("userId", "uid12345");
userIdCookie.setMaxAge(60*60*24*7);
response.addCookie(userIdCookie);

String cookieName = "userId";
Cookie[] cookies = request.getCookies();
if(cookies != null){
    for(int i=0; i<cookies.length; i++){
        Cookie cookie = cookies[i];
        if(cookieName.equals(cookie.getName())){
            doSomeThing(cookie.getValue());
        }
    }
}