设置session，cookies

 Cookie cookie = new Cookie("username",username);
 cookie.setMaxAge(60 * 60 * 24 * 365 * 2);//设置cookie保存时间
 cookie.setPath("/");//cookie有效路径是网站根目录
 con.getResponse().addCookie(cookie);//向客户端写入cookie
 con.setSessionAttr("userLogin", model);  

 HttpSession session = request.getSession();
 session.setMaxInactiveInterval(60*60);//session过期时间
 session.setAttribute("userLogin", model);