不是我写的，但是可用的：       
   public void WxCallback(HttpServletRequest request, HttpServletResponse response) throws Exception {
 log.info("****微信回调开始****");
        BufferedReader br = new BufferedReader(new InputStreamReader(request.getInputStream()));
        String line = null;
        StringBuilder sb = new StringBuilder();
        while ((line = br.readLine()) != null) {
            sb.append(line);
        }
        br.close();
        //sb为微信返回的xml微信返回的所有信息
        String notityXml = sb.toString();
        String resXml = "";
        log.info("接收到的报文" + notityXml);

另外用RequestMapping("/XXXX")