.Net(C#)后台发送Get和Post请求的几种方法总结

1、通过HttpClient发送Get和Post请求

适用平台：.NET Framework 4.5+, .NET Standard 1.1+, .NET Core 1.0+

其它平台的移植版本可以通过Nuget来安装。(Nuget使用方法：http://www.wonhero.com/article/21/)

命名空间：using System.Net.Http;

HttpClient推荐使用单一实例共享使用，发关请求的方法推荐使用异步的方式，代码如下，

private static readonly HttpClient client = new HttpClient();//发送Get请求var responseString = await client.GetStringAsync("http://www.example.com/recepticle.aspx");//发送Post请求var values = new Dictionary{   { "thing1", "hello" },   { "thing2", "world" }};var content = new FormUrlEncodedContent(values);var response = await client.PostAsync("http://www.example.com/recepticle.aspx", content);var responseString = await response.Content.ReadAsStringAsync();

2、通过第三方类库发送Get和Post请求

1）Flurl.Http(可以通过Nuget来安装)

命名空间：using Flurl.Http;

//发送Get请求var responseString = await "http://www.example.com/recepticle.aspx"    .GetStringAsync();//发送Post请求var responseString = await "http://www.example.com/recepticle.aspx"    .PostUrlEncodedAsync(new { thing1 = "hello", thing2 = "world" })    .ReceiveString();

2）RestSharp(可以通过Nuget来安装)

//发送Get和Post请求 RestClient client = new RestClient("http://example.com");//指定请求的url RestRequest req = new RestRequest("resource/{id}", Method.GET);//指定请求的方式，如果Post则改成Method.POSTrequest.AddParameter("name", "value"); // 添加参数到 URL querystringrequest.AddUrlSegment("id", "123"); // 替换上面指定请求方式中的{id}参数//req.AddBody(body); /*如发送post请求，则用req.AddBody()指定body内容*///发送请求得到请求的内容//如果有header可以使用下面方法添加//request.AddHeader("header", "value");IRestResponse response = client.Execute(request);//上传一个文件//request.AddFile("file", path);var content = response.Content; // 未处理的content是string//还可以下面几种方式发送请求//发送请求,反序列化请求结果IRestResponse response2 = client.Execute(request);var name = response2.Data.Name;//发送请求下载一个文件，并保存到path路径client.DownloadData(request).SaveAs(path);// 简单发送异步请求await client.ExecuteAsync(request);// 发送异常请求并且反序列化结果var asyncHandle = client.ExecuteAsync(request, response => {    Console.WriteLine(response.Data.Name);});//终止异步的请求asyncHandle.Abort();

3、比较老一点的方法通过WebRequest发送请求

适用平台：.NET Framework 1.1+, .NET Standard 2.0+, .NET Core 1.0+

命名空间：
using System.Net;
using System.Text;  // for class Encoding
using System.IO;    // for StreamReader

//发送Get请求var request = (HttpWebRequest)WebRequest.Create("http://www.example.com/recepticle.aspx");var response = (HttpWebResponse)request.GetResponse();var responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();//发送Post请求var request = (HttpWebRequest)WebRequest.Create("http://www.example.com/recepticle.aspx");var postData = "thing1=hello";    postData += "&thing2=world";var data = Encoding.ASCII.GetBytes(postData);request.Method = "POST";request.ContentType = "application/x-www-form-urlencoded";request.ContentLength = data.Length;using (var stream = request.GetRequestStream()){    stream.Write(data, 0, data.Length);}var response = (HttpWebResponse)request.GetResponse();var responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();

4、通过WebClient的方式发送请求

适用平台：.NET Framework 1.1+, .NET Standard 2.0+, .NET Core 2.0+

命名空间：
using System.Net;
using System.Collections.Specialized;

using System.Net;using System.Collections.Specialized;//发送Get请求 string url = string.Format("http://localhost:28450/api/values?p1=a&p2=b"); using (var wc = new WebClient()){ Encoding enc = Encoding.GetEncoding("UTF-8"); Byte[] pageData = wc.DownloadData(url); string re = enc.GetString(pageData);}//发送Post请求using (var client = new WebClient()){    var values = new NameValueCollection();    values["thing1"] = "hello";    values["thing2"] = "world";    var response = client.UploadValues("http://www.example.com/recepticle.aspx", values);    var responseString = Encoding.Default.GetString(response);}