c# .net core 下的网络请求代码详解

在这期间，由于.net core 并不基于IIS，我们的过去的网络请求代码在.net core框架下，有可能会出现不兼容，报错的现象。这里大致介绍下在.net core 下如何进行http请求，主要仍然是GET和POST方法，有错误的地方，欢迎指正！

先来说POST,POST我实现了三种方法，前两种基于的原理是完全一致的，后面的有些小小的差异，但他们的本质都是http请求，本质上是无区别的，只是实现方法有所不同。

废话不多说，上代码：

POST异步方法：

/// <summary> /// 异步请求post（键值对形式,可等待的） /// </summary> /// <param name="uri">网络基址(":59315")</param> /// <param name="url">网络的地址("/api/UMeng")</param> /// <param name="formData">键值对List<KeyValuePair<string, string>> formData=new List<KeyValuePair<string, string>>();formData.Add(new KeyValuePair<string, string>("userid", "29122"));formData.Add(new KeyValuePair<string, string>("umengids", "29122"));</param> /// <param name="charset">编码格式</param> /// <param name="mediaType">头媒体类型</param> /// <returns></returns> public async Task<string> HttpPostAsync(string uri, string url, List<KeyValuePair<string, string>> formData=null, string charset="UTF-8", string mediaType="application/x-www-form-urlencoded") { string tokenUri=url; var client=new HttpClient(); client.baseAddress=new Uri(uri); HttpContent content=new FormUrlEncodedContent(formData); content.Headers.ContentType=new MediaTypeHeaderValue(mediaType); content.Headers.ContentType.CharSet=charset; for (int i=0; i < formData.Count; i++) { content.Headers.Add(formData[i].Key, formData[i].Value); } HttpResponseMessage resp=await client.PostAsync(tokenUri, content); resp.EnsureSuccessStatusCode(); string token=await resp.Content.ReadAsStringAsync(); return token; }

POST同步方法：

/// <summary> /// 同步请求post（键值对形式） /// </summary> /// <param name="uri">网络基址(":59315")</param> /// <param name="url">网络的地址("/api/UMeng")</param> /// <param name="formData">键值对List<KeyValuePair<string, string>> formData=new List<KeyValuePair<string, string>>();formData.Add(new KeyValuePair<string, string>("userid", "29122"));formData.Add(new KeyValuePair<string, string>("umengids", "29122"));</param> /// <param name="charset">编码格式</param> /// <param name="mediaType">头媒体类型</param> /// <returns></returns> public string HttpPost(string uri, string url, List<KeyValuePair<string, string>> formData=null, string charset="UTF-8", string mediaType="application/x-www-form-urlencoded") { string tokenUri=url; var client=new HttpClient(); client.baseAddress=new Uri(uri); HttpContent content=new FormUrlEncodedContent(formData); content.Headers.ContentType=new MediaTypeHeaderValue(mediaType); content.Headers.ContentType.CharSet=charset; for (int i=0; i < formData.Count; i++) { content.Headers.Add(formData[i].Key, formData[i].Value); } var res=client.PostAsync(tokenUri, content); res.Wait(); HttpResponseMessage resp=res.Result; var res2=resp.Content.ReadAsStringAsync(); res2.Wait(); string token=res2.Result; return token; }

遗憾的是，同步方法也是基于异步实现的，个人认为这样做会加大系统开销。如果各位有其他的高效实现，请不吝赐教！

接下来是通过流的方式进行POST：

public string Post(string url, string data, Encoding encoding, int type) { try { HttpWebRequest req=WebRequest.CreateHttp(new Uri(url)); if (type==1) { req.ContentType="application/json;charset=utf-8"; } else if (type==2) { req.ContentType="application/xml;charset=utf-8"; } else { req.ContentType="application/x-www-form-urlencoded;charset=utf-8"; } req.Method="POST"; //req.Accept="text/xml,text/javascript"; req.ContinueTimeout=60000; byte[] postData=encoding.GetBytes(data); Stream reqStream=req.GetRequestStreamAsync().Result; reqStream.Write(postData, 0, postData.Length); reqStream.Dispose(); var rsp=(HttpWebResponse)req.GetResponseAsync().Result; var result=GetResponseAsString(rsp, encoding); return result; } catch (Exception ex) { throw; } }

private string GetResponseAsString(HttpWebResponse rsp, Encoding encoding) { Stream stream=null; StreamReader reader=null; try { // 以字符流的方式读取HTTP响应 stream=rsp.GetResponseStream(); reader=new StreamReader(stream, encoding); return reader.ReadToEnd(); } finally { // 释放资源 if (reader !=null) reader.Dispose(); if (stream !=null) stream.Dispose(); if (rsp !=null) rsp.Dispose(); } }