C# 通过 HttpWebRequest发送数据以及服务器通过Request请求获取数据

C# 通过 HttpWebRequest发送数据以及服务器通过Request请求获取数据, 后台请求的三种类型"application/x-www-form-urlencoded"和"multipart/form-data"以及"application/json"，对应的服务器端应该获取数据参数的方法

C#中HttpWebRequest的用法详解 可参考：

C#中HttpWebRequest的用法详解
C# HttpWebRequest详解
C# 服务器通过Request获取参数 可参考：
C# WebService 接口 通过Request请求获取json参数

一、客户端和服务器传输数据的类

1、后台程序发送HTTP请求的Class，服务器端也要添加该类

namespace WebApiInvoke{    /// 
    /// 后台程序发送HTTP请求数据的类    ///     class RequestDataModel    {        /// 
        /// 姓名        ///         public string DataName { get; set; }        /// 
        /// 性别        ///         public string DataSex { get; set; }        /// 
        /// 结果        ///         public string DataResult { get; set; }        /// 
        /// 年龄        ///         public int DataAge { get; set; }    }}

2、服务端返回HTTP请求的数据class，客户端也要有

namespace ServiceTest{    /// 
    /// WebService 服务端返回的类    ///     public class WebServiceWriteBack    {        public bool Success { get; set; } = true;        public string Data { get; set; } = string.Empty;    }}

二、“application/json”：

1、后台程序(客户端)发送HTTP请求(request.Method = “POST”、request.ContentType = “application/json”),

a.客户端代码：

namespace WebApiInvoke{    class HttpApiRequestHelper    {        /// 
        /// 使用HttpWebRequest发送一个POST请求         ///         /// 请求的地址        /// 发送的数据对象        ///         public static string HttpJsonPost(string url, object dto)        {            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);            request.Method = "POST";            request.KeepAlive = false;            request.AllowAutoRedirect = true;            request.Accept = "application/json";            request.ContentType = "application/json";            string strContent = JsonConvert.SerializeObject(dto); //序列化为字符串，可以使用自己项目中封装的json方法            using (StreamWriter dataStream = new StreamWriter(request.GetRequestStream()))            {                dataStream.Write(strContent);            }            //  获取服务器返回的响应体            HttpWebResponse response = (HttpWebResponse)request.GetResponse();            string encoding = response.ContentEncoding;            if (encoding == null || encoding.Length < 1)            {                encoding = "UTF-8"; //默认编码              }            StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.GetEncoding(encoding));            string retString = reader.ReadToEnd();            return retString;        }   }}

服务器端通过Request.InputStream获取json数据，并做相应的处理；
需要NuGet程序包中安装Microsoft.AspNetCore.Mvc.WebApiCompatShim，并usingSystem.Web.Http;

b.服务器端对应的代码

using Newtonsoft.Json;using System;using System.IO;using System.Web;using System.Web.Http;namespace ServiceTest{    /// WebService 接口 通过Request请求获取json参数    class GetRequestDataHelper : ApiController    {        /// 
        /// 通过Request请求获取json参数        /// 对应request.ContentType = "application/json"        ///         ///         public WebServiceWriteBack GetRequestJsonData()        {        // 服务器端回写数据库的类            WebServiceWriteBack writeBack = new WebServiceWriteBack();            HttpContextBase context = Request.Properties["MS_HttpContext"] as HttpContextBase;            HttpRequestBase request = context.Request;            string data = string.Empty;            using (Stream stream = request.InputStream)// 读取Json数据            {                stream.Position = 0;                using (StreamReader streamReader = new StreamReader(stream))                {                    data = streamReader.ReadToEnd();                }            }            // 将Json数据转换为对象            RequestDataModel data1 = JsonConvert.DeserializeObject<RequestDataModel>(data);            #region 对传进来的 DataModel 进行处理 并对要回写的WebServiceWriteBack类进行赋值            if (string.IsNullOrEmpty(data1.DataSex))            {                writeBack.Success = true;                writeBack.Data = "成功了！";            }            #endregion            return writeBack;        }    }}

三、表单：

1、传统的表单数据是"DataName=1&DataSex=dadada&DataResult=S201FR&DataAge=1"一个字符串中间用‘&’分割；

后台程序(客户端)发送HTTP请求(request.Method = “POST”、request.ContentType = “application/x-www-form-urlencoded”),

a.客户端代码：

        /// 
        /// HttpWebRequest Post请求        /// application/x-www-form-urlencoded        /// "DataName=1&DataSex=dadada&DataResult=S201FR&DataAge=1"        ///         /// 请求地址        /// 请求参数(json格式请求数据时contentType必须指定为application/json)        /// 返回结果        /// 请求类型        /// 返回结果        public static bool WebHttpPost(string postUrl, string postData, out string result, string contentType = "application/x-www-form-urlencoded")        {            try            {                Encoding encoding = Encoding.GetEncoding("gb2312");                byte[] byteArray = encoding.GetBytes(postData);                HttpWebRequest httpWebRequest = (HttpWebRequest)WebRequest.Create(postUrl);                httpWebRequest.Method = "POST";                httpWebRequest.ContentType = contentType;                httpWebRequest.ContentLength = byteArray.Length;                httpWebRequest.AllowAutoRedirect = true;                using (Stream stream = httpWebRequest.GetRequestStream())                {                    stream.Write(byteArray, 0, byteArray.Length); // 写入参数                                  }//  获取服务器返回的响应体                HttpWebResponse httpWebResponse = httpWebRequest.GetResponse() as HttpWebResponse;                using (Stream responseStream = httpWebResponse.GetResponseStream())                {                    StreamReader streamReader = new StreamReader(responseStream, Encoding.GetEncoding("UTF-8"));                    result = streamReader.ReadToEnd(); // 请求返回的数据                    streamReader.Close();                }                return true;            }            catch (Exception ex)            {                result = ex.Message;                return false;            }        }

b.服务器端通过Request.Form获取表单数据，并做相应的处理；

using Newtonsoft.Json;using System;using System.IO;using System.Web;using System.Web.Http;namespace ServiceTest{        /// 
        /// 通过Request请求获取表单参数        /// 对应contentType = "application/x-www-form-urlencoded"和contentType =  "multipart/form-data"        ///         ///         public WebServiceWriteBack GetRequestFromData()        {            // 服务器端回写数据库的类            WebServiceWriteBack writeBack = new WebServiceWriteBack();            HttpContextBase context = Request.Properties["MS_HttpContext"] as HttpContextBase;            HttpRequestBase request = context.Request;                        RequestDataModel data1 = new RequestDataModel()            {                DataName = request.Form["DataName"]?.ToString(),                DataSex = request.Form["DataSex"]?.ToString(),                DataAge = Convert.ToInt32(request.Form["DataAge"]?.ToString()),                DataResult = request.Form["DataResult"]?.ToString()            };            #region 对传进来的 DataModel 进行处理 并对要回写的WebServiceWriteBack类进行赋值            if (string.IsNullOrEmpty(data1.DataSex))            {                writeBack.Success = true;                writeBack.Data = "成功了！";            }            #endregion            return writeBack;        }    }}

2、“multipart/form-data”

包含异步请求方法HttpPostAsync和HttpPostFromData方法

a.客户端代码，两个方法

using Newtonsoft.Json;using Newtonsoft.Json.Linq;using System;using System.Collections.Generic;using System.IO;using System.Linq;using System.Net;using System.Text;namespace WebApiInvoke{    class HttpApiRequestHelper    {        /// 
        /// Async异步请求 POST        ///         /// 请求的地址        /// Json字符串        ///         public static string HttpPostAsync(string urlStr, string jsonStr)        {            string content = "";            try            {                Dictionary<string, string> map = JsonStringToKeyValuePairs(jsonStr);                var mfdc = new System.Net.Http.MultipartFormDataContent();                mfdc.Headers.Add("ContentType", "multipart/form-data");//声明头部                foreach (string key in map.Keys)                {                    mfdc.Add(new System.Net.Http.StringContent(map[key]), key);//参数, 内容在前,参数名称在后                }                var clientTask = new System.Net.Http.HttpClient().PostAsync(urlStr, mfdc);//发起异步请求                clientTask.Wait();//等待请求结果                if (clientTask.Result.IsSuccessStatusCode)                {                    //请求正常                    var resultTask = clientTask.Result.Content.ReadAsStringAsync();//异步读取返回内容                    resultTask.Wait();//等读取返回内容                    content = resultTask.Result;//返回内容字符串                }                else                {                    //请求异常                    content = "失败";                }            }            catch (Exception ex)            {                content = ex.Message;            }            return content;        }        /// 
        /// multipart/form-data POST请求        ///         /// 请求的地址        /// Json字符串        ///         public static string HttpPostFromData(string url, string jsonStr)        {            string content = "";            try            {                string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x");                byte[] boundarybytes = Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");                byte[] endbytes = Encoding.ASCII.GetBytes("\r\n--" + boundary + "--\r\n");                HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);                request.ContentType = "multipart/form-data; boundary=" + boundary;                request.Method = WebRequestMethods.Http.Post;                request.KeepAlive = true;                request.Timeout = -1;                CredentialCache credentialCache = new CredentialCache();                credentialCache.Add(new Uri(url), "Basic", new NetworkCredential("user", "user"));                request.Credentials = credentialCache;                request.ServicePoint.Expect100Continue = false;                Dictionary<string, string> map = JsonStringToKeyValuePairs(jsonStr);                using (Stream stream = request.GetRequestStream())                {                    //1.1 key/value                    string formdataTemplate = "Content-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}";                    if (map != null)                    {                        foreach (string key in map.Keys)                        {stream.Write(boundarybytes, 0, boundarybytes.Length);string formitem = string.Format(formdataTemplate, key, map[key]);byte[] formitembytes = Encoding.GetEncoding("UTF-8").GetBytes(formitem);stream.Write(formitembytes, 0, formitembytes.Length);                        }                    }                    stream.Write(endbytes, 0, endbytes.Length);                }                //2.WebResponse                HttpWebResponse response = request.GetResponse() as HttpWebResponse;                using (Stream responsestream = response.GetResponseStream())                {                    using (StreamReader sr = new StreamReader(responsestream))                    {                        content = sr.ReadToEnd();                    }                }            }            catch (Exception ex)            {                content = ex.Message;            }            return content;        }        /// 
        /// JSON格式转Dictionary        ///         ///         ///         public static Dictionary<string, string> JsonStringToKeyValuePairs(string jsonStr)        {            char jsonBeginToken = '{';            char jsonEndToken = '}';            if (string.IsNullOrEmpty(jsonStr))            {                return null;            }            //验证json字符串格式            if (jsonStr[0] != jsonBeginToken || jsonStr[jsonStr.Length - 1] != jsonEndToken)            {                throw new ArgumentException("非法的Json字符串!");            }            var resultDic = new Dictionary<string, string>();            var jobj = JObject.Parse(jsonStr);            JsonOn(jobj, resultDic);            return resultDic;        }        private static Dictionary<string, string> JsonOn(JToken jobT, Dictionary<string, string> Dic)        {            //找出包含嵌套的字段列            if (jobT is JObject jobj && jobj.Properties().Count() > 0)            {                foreach (var item in jobj.Properties())                {                    JsonProperties(item, Dic);                }            }            else            {                Dic.Add(jobT.Path, jobT.ToString());                return Dic;            }            return Dic;        }        private static Dictionary<string, string> JsonProperties(JProperty jobj, Dictionary<string, string> Dic)        {            return JsonOn(jobj.Value, Dic);        }    }}

b. 服务器方法同1.b 这里不再赘述

来源地址：https://blog.csdn.net/qq_44618510/article/details/131328581