C#中POST数据和接收的几种方式（抛砖引玉）

POST方式提交数据，一种众所周知的方式：

html页面中使用form表单提交，接收方式，使用Request.Form[""]或Request.QueryString[""]来获取。

 

这里介绍另外一种POST方式和接收方式，就是将整个数据作为加入到数据流中提交和接收

接收方式:

Stream s = System.Web.HttpContext.Current.Request.InputStream;byte[] b = new byte[s.Length];s.Read(b, 0, (int)s.Length);return Encoding.UTF8.GetString(b);

只需要从input Stream中读取byte数据，然后转为string，再解析即可。如果要回复响应消息只需要用：Response.Write()  输出即可（和普通的页面输出一样）。

 

主动POST发送方式：

            HttpWebRequest webrequest = (HttpWebRequest)HttpWebRequest.Create(url);            webrequest.Method = "post";            byte[] postdatabyte = Encoding.UTF8.GetBytes(postData);            webrequest.ContentLength = postdatabyte.Length;            Stream stream;            stream = webrequest.GetRequestStream();            stream.Write(postdatabyte, 0, postdatabyte.Length);            stream.Close();            using (var httpWebResponse = webrequest.GetResponse())            using (StreamReader responseStream = new StreamReader(httpWebResponse.GetResponseStream()))            {                String ret = responseStream.ReadToEnd();                T result = XmlDeserialize<T>(ret);                return result;            }

使用HttpClient对象发送

 public static  string   PostXmlResponse(string url, string xmlString)                     {            HttpContent httpContent = new StringContent(xmlString);            httpContent.Headers.ContentType = new MediaTypeHeaderValue("application/json");            HttpClient httpClient = new HttpClient();                       HttpResponseMessage response = httpClient.PostAsync(url, httpContent).Result;            if (response.IsSuccessStatusCode)            {                Task<string> t = response.Content.ReadAsStringAsync();                return t.Result;            }            return string.Empty;        }         

 

从代码中可以看出仅仅是将字符串转为byte[] 类型，并加入到请求流中，进行请求即可达到POST效果，该种POST方式与上边所提到的接收方式相互配合使用。

下面一种方式是以键值对的方式主动POST传输的。

 

　　　　 /// <summary>        /// 发起httpPost 请求，可以上传文件        /// </summary>        /// <param name="url">请求的地址</param>        /// <param name="files">文件</param>        /// <param name="input">表单数据</param>        /// <param name="endoding">编码</param>        /// <returns></returns>        public static string PostResponse(string url, UpLoadFile[] files, Dictionary<string, string> input, Encoding endoding)        {            string boundary = "----------------------------" + DateTime.Now.Ticks.ToString("x");            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);            request.ContentType = "multipart/form-data; boundary=" + boundary;            request.Method = "POST";            request.KeepAlive = true;            //request.Credentials = CredentialCache.DefaultCredentials;            request.Expect = "";            MemoryStream stream = new MemoryStream();            byte[] line = Encoding.ASCII.GetBytes("--" + boundary + "\r\n");            byte[] enterER = Encoding.ASCII.GetBytes("\r\n");            ////提交文件            if (files != null)            {                string fformat = "Content-Disposition:form-data; name=\"{0}\";filename=\"{1}\"\r\nContent-Type:{2}\r\n\r\n";                foreach (UpLoadFile file in files)                {                    stream.Write(line, 0, line.Length);        //项目分隔符                    string s = string.Format(fformat, file.Name, file.FileName, file.Content_Type);                    byte[] data = Encoding.UTF8.GetBytes(s);                    stream.Write(data, 0, data.Length);                    stream.Write(file.Data, 0, file.Data.Length);                    stream.Write(enterER, 0, enterER.Length);  //添加\r\n                }            }            //提交文本字段            if (input != null)            {                string format = "--" + boundary + "\r\nContent-Disposition:form-data;name=\"{0}\"\r\n\r\n{1}\r\n";    //自带项目分隔符                foreach (string key in input.Keys)                {                    string s = string.Format(format, key, input[key]);                    byte[] data = Encoding.UTF8.GetBytes(s);                    stream.Write(data, 0, data.Length);                }            }            byte[] foot_data = Encoding.UTF8.GetBytes("--" + boundary + "--\r\n");      //项目最后的分隔符字符串需要带上--              stream.Write(foot_data, 0, foot_data.Length);            request.ContentLength = stream.Length;            Stream requestStream = request.GetRequestStream(); //写入请求数据            stream.Position = 0L;            stream.CopyTo(requestStream); //            stream.Close();            requestStream.Close();            try            {                HttpWebResponse response;                try                {                    response = (HttpWebResponse)request.GetResponse();                    try                    {                        using (var responseStream = response.GetResponseStream())                        using (var mstream = new MemoryStream())                        {                            responseStream.CopyTo(mstream);                            string message = endoding.GetString(mstream.ToArray());                            return message;                        }                    }                    catch (Exception ex)                    {                        throw ex;                    }                }                catch (WebException ex)                {                    //response = (HttpWebResponse)ex.Response;                    //if (response.StatusCode == HttpStatusCode.BadRequest)                    //{                    //    using (Stream data = response.GetResponseStream())                    //    {                    //        using (StreamReader reader = new StreamReader(data))                    //        {                    //            string text = reader.ReadToEnd();                    //            Console.WriteLine(text);                    //        }                    //    }                    //}                    throw ex;                }            }            catch (Exception ex)            {                throw ex;            }        }

 

通过两种主动POST提交 的代码可以看出，其主要区别在于发送前的数据格式 ContentType 的值。

下面列举几种常用的ContentType 值，并简述他们的区别

Content-Type 被指定为 application/x-www-form-urlencoded 时候，传输的数据格式需要如  title=test&sub%5B%5D=1&sub%5B%5D=2&sub%5B%5D=3 所示格式，才能正确解析

Content-Type 被指定为 multipart/form-data 时候，所需格式如下面代码块中所示

Content-Type:multipart/form-data; boundary=----WebKitFormBoundaryrGKCBY7qhFd3TrwA------WebKitFormBoundaryrGKCBY7qhFd3TrwAContent-Disposition: form-data; name="text"title------WebKitFormBoundaryrGKCBY7qhFd3TrwAContent-Disposition: form-data; name="file"; filename="chrome.png"Content-Type: image/pngPNG ... content of chrome.png ...------WebKitFormBoundaryrGKCBY7qhFd3TrwA--

Content-Type 也可以被指定为 application/json ，最终传输格式为 {"title":"test","sub":[1,2,3]}  至于如何接收本人未经尝试，但是可以肯定的讲使用文章开头所说的接收方式接收后转为string类型再

发序列化是可行的。

 

Content-Type指定为 text/xml  ，传输的数据格式为

<?xml version="1.0"?><methodCall>    <methodName>examples.getStateName</methodName>    <params>        <param>            <value><i4>41</i4></value>        </param>    </params></methodCall>

此种方式，本人亦未经尝试，接受方式可以参考上文中 application/json 的接收方式。

由于xml的格式传输数据，使用相对较少，相信很多同学亦不知道如何将字符串解析为对象，下文将提供一种转换方式，供参考

            XmlDocument doc = new XmlDocument();            doc.LoadXml(weixin);//读取xml字符串            XmlElement root = doc.DocumentElement;            ExmlMsg xmlMsg = new ExmlMsg()            {                FromUserName = root.SelectSingleNode("FromUserName").InnerText,                ToUserName = root.SelectSingleNode("ToUserName").InnerText,                CreateTime = root.SelectSingleNode("CreateTime").InnerText,                MsgType = root.SelectSingleNode("MsgType").InnerText,            };            if (xmlMsg.MsgType.Trim().ToLower() == "text")            {                xmlMsg.Content = root.SelectSingleNode("Content").InnerText;            }            else if (xmlMsg.MsgType.Trim().ToLower() == "event")            {                xmlMsg.EventName = root.SelectSingleNode("Event").InnerText;            }            return xmlMsg;

        private class ExmlMsg        {            /// <summary>            /// 本公众账号            /// </summary>            public string ToUserName { get; set; }            /// <summary>            /// 用户账号            /// </summary>            public string FromUserName { get; set; }            /// <summary>            /// 发送时间戳            /// </summary>            public string CreateTime { get; set; }            /// <summary>            /// 发送的文本内容            /// </summary>            public string Content { get; set; }            /// <summary>            /// 消息的类型            /// </summary>            public string MsgType { get; set; }            /// <summary>            /// 事件名称            /// </summary>            public string EventName { get; set; }        }

 

至此，相信一部分同学能有所得。由于本人水平一般，文中所述可能有纰漏之处，还请路过高手指出，同时也欢迎在评论区贴出更好的 发送和接受方式，供大家学习和交流。