1、回调接口解析代码如下：

private Map<String, String> getRequestParam(HttpServletRequest request) {
    InputStream inputStream = null;
    InputStreamReader inputStreamReader = null;
    BufferedReader reader = null;
    try {
        inputStream = request.getInputStream();
        inputStreamReader = new InputStreamReader(inputStream);
        reader = new BufferedReader(inputStreamReader);
        String line = null;
        StringBuilder strXML = new StringBuilder();
        while ((line = reader.readLine()) != null) {
            strXML.append(line);
        }
        // 问题：这里的strXML.toString() 的结果是空串
        Map<String, String> paramMap = WXPayUtil.xmlToMap(strXML.toString());
        return paramMap;
    } catch (Exception e) {
        throw new PayException(-1, "wxPayCallBackFail", e);
    } finally {
        try {
            if (reader != null) {
                reader.close();
            }
            if (inputStreamReader != null) {
                inputStreamReader.close();
            }
            if (inputStream != null) {
                inputStream.close();
            }
        } catch (IOException e) {
            logger.error("wxPayCallBackFail", e);
        }
    }
}

2、每天凌晨03:12 、04:26 、05:39 左右会发生上述情况至少三次；

期望能给与答复，谢谢。