自己用的各种工具类(不喜勿喷)

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();
        }
    }