@RequestMapping("/checkLogin.do")
public String checkLogin(Map map, HttpSession httpSession, String username, String password) {

    JSONObject userJson = userService.checkLogin(username, password);

    if ((Integer) userJson.get("success") == 0) {
        httpSession.setAttribute("userinfo", userJson);
        return "redirect:/index.do";
    } else {
        map.put("error", -1);
        return "login";
}

@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse arg1, Object arg2) throws Exception {
        String requestURI = request.getRequestURI();
        HttpSession session = request.getSession();
        String userinfo= (String) session.getAttribute("userinfo");
        if (userinfo!= null) {
            return true;
        } else {
            arg1.sendRedirect("/login.do");
            return false;
        }

}