对于新手小白来说添加摄像机到硬盘录像机上面总会出问题，添加成功后，显示不在线怎么办?问题出在设备设置上面，2) 检查摄像头的设置或参数是否出现不匹配，比如网络问题、onvif协议、视频的压缩格式等等，需要电脑访问摄像头配置，更改一下就可以了。
看来wget之前也存在此类问题，于是继续搜索标准，输出如下:The presence of a message body in a response depends on both the request method to which it is responding and the response status code . Responses to the HEAD request method never include a message body because the associated response header fields ， if present， indicate only what their values would have been if the request method had been GET . 2xx responses to a CONNECT request method switch to tunnel mode instead of having a message body. All 1xx ， 204 ， and 304 responses do not include a message body. All other responses do include a message body， although the body might be of zero length.
