https://developers.weixin.qq.com/doc/offiaccount/Message_Management/Passive_user_reply_message.html 接口地址 /** * 微信服务器回调 */ @Override public String getOpenidAndTicket(HttpServletRequest request, HttpServletResponse response) throws Exception { String message = "success"; request.setCharacterEncoding("UTF-8"); response.setCharacterEncoding("UTF-8"); Map<String, String> map = MessageUtil.xmlToMap(request); log.info(":::::::::微信返回map::::::::" + map.toString()); String openid = map.get("FromUserName"); String kfz = map.get("ToUserName"); String MsgType = map.get("MsgType"); log.info(":::::::::MsgType::::::::" + MsgType); log.info(":::::::::XConstants.MESSAGE_EVENT::::::::" + WXConstants.MESSAGE_EVENT); if (MsgType.equals(WXConstants.MESSAGE_EVENT)) { //从集合中，获取是哪一种事件传入 String eventType = map.get("Event"); //对获取到的参数进行处理 String eventKey = map.get("EventKey"); //扫描带参数的二维码，如果用户未关注，则可关注公众号，事件类型为subscribe；用户已关注，则事件类型为SCAN String ticket = map.get("Ticket"); if (eventType.equals(WXConstants.MESSAGE_SUBSCRIBE)) { // wxPolling(ticket); // 创建document对象 Document document = DocumentHelper.createDocument(); // 创建根节点bookRoot Element xml = document.addElement("xml"); // 向根节点中添加第一个节点 Element toUserName = xml.addElement("ToUserName"); // 向子节点中添加属性 toUserName.addCDATA(openid); Element fromUserName = xml.addElement("FromUserName"); fromUserName.addCDATA(appFromUserName); Element createTime = xml.addElement("CreateTime"); createTime.addCDATA(String.valueOf(System.currentTimeMillis())); Element msgType = xml.addElement("MsgType"); msgType.addCDATA("text"); Element content = xml.addElement("Content"); content.addCDATA("关注回复"); message = document.getRootElement().asXML(); log.info("关注自动回复，openid{}，回复信息为：{}", openid, message); } e } log.info("返回微信服务器消息内容为：{}", message); return message; } 代码如上，第一次关注返回信息时正常，第二次扫码后会提示“该公众号提供的服务出现故障，请稍后再试”，请问是什么原因呢？