$.ajax GET请求案例（Controller的另外一种写法）

$.ajax({
            type: "GET",
            url: getRootPath() + "/getDatas.do",
            contentType: 'application/json;charset=utf-8', //设置请求头信息
            data: "devId=" + devId, //必须是字符串
            dataType: "json",
            success: function (res) {
                if (res.rtnCode == 0) {
                    successToast(res.msg);
                }
            },
            error: function (result) {
                errorToast(result.msg);
            }
        });

@RequestMapping(value = "/getDatas.do", method = RequestMethod.GET)
    @ResponseBody
    public Result getDatas(HttpServletRequest request, @RequestParam(defaultValue = "") String devId) {
        Result result = new Result()；
        result.setMsg("查询成功：" + devId)；
        return result;
    }