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

namespaceWebApiInvoke{/// <summary>/// 后台程序发送HTTP请求数据的类/// </summary>classRequestDataModel{/// <summary>/// 姓名/// </summary>publicstring DataName {get;set;}/// <summary>/// 性别/// </summary>publicstring DataSex {get;set;}/// <summary>/// 结果/// </summary>publicstring DataResult {get;set;}/// <summary>/// 年龄/// </summary>publicint DataAge {get;set;}}}

2、服务端返回HTTP请求的数据class，客户端也要有

namespaceServiceTest{/// <summary>/// WebService 服务端返回的类/// </summary>publicclassWebServiceWriteBack{publicbool Success {get;set;}=true;publicstring 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：

namespaceWebApiInvoke{classHttpApiRequestHelper{/// <summary>/// 使用HttpWebRequest发送一个POST请求 /// </summary>/// <param name="url">请求的地址</param>/// <param name="dto">发送的数据对象</param>/// <returns></returns>publicstaticstringHttpJsonPost(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 =newStreamWriter(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 =newStreamReader(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

usingNewtonsoft.Json;usingSystem;usingSystem.IO;usingSystem.Web;usingSystem.Web.Http;namespaceServiceTest{/// WebService 接口 通过Request请求获取json参数classGetRequestDataHelper:ApiController{/// <summary>/// 通过Request请求获取json参数/// 对应request.ContentType = "application/json"/// </summary>/// <returns></returns>publicWebServiceWriteBackGetRequestJsonData(){// 服务器端回写数据库的类WebServiceWriteBack writeBack =newWebServiceWriteBack();HttpContextBase context = Request.Properties["MS_HttpContext"]asHttpContextBase;HttpRequestBase request = context.Request;string data =string.Empty;using(Stream stream = request.InputStream)// 读取Json数据{
                stream.Position =0;using(StreamReader streamReader =newStreamReader(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！";}#endregionreturn 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：

/// <summary>/// HttpWebRequest Post请求/// application/x-www-form-urlencoded/// "DataName=1&DataSex=dadada&DataResult=S201FR&DataAge=1"/// </summary>/// <param name="postUrl">请求地址</param>/// <param name="postData">请求参数(json格式请求数据时contentType必须指定为application/json)</param>/// <param name="result">返回结果</param>/// <param name="contentType">请求类型</param>/// <returns>返回结果</returns>publicstaticboolWebHttpPost(string postUrl,string postData,outstring 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()asHttpWebResponse;using(Stream responseStream = httpWebResponse.GetResponseStream()){StreamReader streamReader =newStreamReader(responseStream, Encoding.GetEncoding("UTF-8"));
                    result = streamReader.ReadToEnd();// 请求返回的数据
                    streamReader.Close();}returntrue;}catch(Exception ex){
                result = ex.Message;returnfalse;}}

b.服务器端通过Request.Form获取表单数据，并做相应的处理；

usingNewtonsoft.Json;usingSystem;usingSystem.IO;usingSystem.Web;usingSystem.Web.Http;namespaceServiceTest{/// <summary>/// 通过Request请求获取表单参数/// 对应contentType = "application/x-www-form-urlencoded"和contentType =  "multipart/form-data"/// </summary>/// <returns></returns>publicWebServiceWriteBackGetRequestFromData(){// 服务器端回写数据库的类WebServiceWriteBack writeBack =newWebServiceWriteBack();HttpContextBase context = Request.Properties["MS_HttpContext"]asHttpContextBase;HttpRequestBase request = context.Request;RequestDataModel data1 =newRequestDataModel(){
                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！";}#endregionreturn 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

usingNewtonsoft.Json;usingNewtonsoft.Json.Linq;usingSystem;usingSystem.Collections.Generic;usingSystem.IO;usingSystem.Linq;usingSystem.Net;usingSystem.Text;namespaceWebApiInvoke{classHttpApiRequestHelper{/// <summary>/// Async异步请求 POST/// </summary>/// <param name="urlStr">请求的地址</param>/// <param name="jsonStr">Json字符串</param>/// <returns></returns>publicstaticstringHttpPostAsync(string urlStr,string jsonStr){string content ="";try{Dictionary<string,string> map =JsonStringToKeyValuePairs(jsonStr);var mfdc =newSystem.Net.Http.MultipartFormDataContent();
                mfdc.Headers.Add("ContentType","multipart/form-data");//声明头部foreach(string key in map.Keys){
                    mfdc.Add(newSystem.Net.Http.StringContent(map[key]), key);//参数, 内容在前,参数名称在后}var clientTask =newSystem.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;}/// <summary>/// multipart/form-data POST请求/// </summary>/// <param name="url">请求的地址</param>/// <param name="jsonStr">Json字符串</param>/// <returns></returns>publicstaticstringHttpPostFromData(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 =newCredentialCache();
                credentialCache.Add(newUri(url),"Basic",newNetworkCredential("user","user"));
                request.Credentials = credentialCache;

                request.ServicePoint.Expect100Continue =false;Dictionary<string,string> map =JsonStringToKeyValuePairs(jsonStr);using(Stream stream = request.GetRequestStream()){//1.1 key/valuestring 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.WebResponseHttpWebResponse response = request.GetResponse()asHttpWebResponse;using(Stream responsestream = response.GetResponseStream()){using(StreamReader sr =newStreamReader(responsestream)){
                        content = sr.ReadToEnd();}}}catch(Exception ex){
                content = ex.Message;}return content;}/// <summary>/// JSON格式转Dictionary/// </summary>/// <param name="jsonStr"></param>/// <returns></returns>publicstaticDictionary<string,string>JsonStringToKeyValuePairs(string jsonStr){char jsonBeginToken ='{';char jsonEndToken ='}';if(string.IsNullOrEmpty(jsonStr)){returnnull;}//验证json字符串格式if(jsonStr[0]!= jsonBeginToken || jsonStr[jsonStr.Length -1]!= jsonEndToken){thrownewArgumentException("非法的Json字符串!");}var resultDic =newDictionary<string,string>();var jobj = JObject.Parse(jsonStr);JsonOn(jobj, resultDic);return resultDic;}privatestaticDictionary<string,string>JsonOn(JToken jobT,Dictionary<string,string> Dic){//找出包含嵌套的字段列if(jobT isJObject 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;}privatestaticDictionary<string,string>JsonProperties(JProperty jobj,Dictionary<string,string> Dic){returnJsonOn(jobj.Value, Dic);}}}

b. 服务器方法同1.b 这里不再赘述