public ActionForward getList(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response){
        PrintWriter out = null;
        String realname=null;
        Integer pageno = Common.PAGE_PAGENO;
        Integer pagesize = Common.PAGE_SIZE;
        JSONObject json = new JSONObject();
        
        List<Users> list = new ArrayList<Users>(); // 不知道你的list 取的是什么，暂且为用户list 吧
        List<Map<String,Object>> list_user = new ArrayList<Map<String,Object>>();
        PageModel user_page = new PageModel();
        list = .......;//这里调用你的方法得到list
        
        if(!list.isEmpty()){ // 对list进行简单的判断
            for(Users _user:list){
                Map _map = new HashMaps();//这里可能会提示让你加泛型，不用鸟
                Map<String,Object> tmp_map = new HashMap<String,Object>();//这个是放那json结构里面的那个小结构的'stats'
                _map.put("id", _user.getId());
                _map.put("name", _user.getName());
                tmp_map.put("fileCount",_user.getFiles().getFileCount())
                tmp_map.put("fileSize", _user.getFiles.getFilesize());
                _map.put("stats",tmp_map);
                list_user.add(_map);
            }
        }
        try{
            json.put("users_", list_user);
            json.put("totalPages", user_page.getTotalPages());
            json.put("_size", user_page.getPageSize());
            json.put("_pno", user_page.getPageNo());
            json.put("_trs", user_page.getTotalRecords());
        }catch(Exception e){
            this.log.error("User JSON Error:"+e.getMessage());
        }
        out.write(json.toString());
        out.flush();
        out.close();
        return null;
    }