public static String list2JsonArray(List list) {        StringBuffer str = new StringBuffer("[");        if (list != null && list.size() > 0) {            int len = list.size();            Object map = null;            for (int i = 0; i < len; i++) {                map = list.get(i);                if (i > 0) {                    str.append(",");                }                str.append(JSONUtil.object2json(map));            }        }        str.append("]");        return str.toString();    }

//向前端返回json字符串    public void outString(String json) {        PrintWriter print = null;        try {            HttpServletResponse response;            response = this.getResponse();            response.setContentType("text/json;charset=UTF-8");            response.setHeader("Cache-Control", "no-cache");            response.setHeader("Pargma", "no-cache");            response.setDateHeader("Expires", 0);            print = this.getResponse().getWriter();            print.write(json);        } catch (IOException e) {            e.printStackTrace();        }    }