JSON--List集合转换成JSON对象

List<Article> al = articleMng.find(f);
            System.out.println(al.size());
            HttpServletResponse hsr = ServletActionContext.getResponse();
            if(null == al){
                return ;
            }
            for(Article a : al){
                System.out.println(a.getId()+a.getDescription()+a.getTitle());
            }
            JSONArray json = new JSONArray();
            for(Article a : al){
                JSONObject jo = new JSONObject();
                jo.put("id", a.getId());
                jo.put("title", a.getTitle());
                jo.put("desc", a.getDescription());
                json.put(jo);
            }
            try {
                System.out.println(json.toString());
                hsr.setCharacterEncoding("UTF-8");
                hsr.getWriter().write(json.toString());
            } catch (IOException e) {
                e.printStackTrace();
            }