一、 HttpWebRequest 方式
支持.net 4.5 以下。一些老项目无法升级高版本的项目还用的到。例如支持XP系统的winfrom程序
可以携带cookie，使用HttpWebRequest的SupportsCookieContainer属性
public string HttpRequest() { HttpWebResponse response = null; StreamReader resultReader = null; Dictionary<string, object> parameter = new Dictionary<string, object>() { { "p1","v1"}, { "p2","v2"} }; var parameterString = JsonConvert.SerializeObject(parameter); try { HttpWebRequest request = (HttpWebRequest)WebRequest.Create("htt://url"); request.Method = "POST"; request.ContentType = "application/json; charset=UTF-8"; request.Headers = new WebHeaderCollection { { "Header1", "v1" }, { "Header2", "v2" } }; //设置参数 byte[] data = Encoding.UTF8.GetBytes(parameterString); request.ContentLength = data.Length; using (Stream newStream = request.GetRequestStream()) { newStream.Write(data, 0, data.Length); }; //获取正确或错误结果 try { response = (HttpWebResponse)request.GetResponse(); } catch (WebException ex) { response = (HttpWebResponse)ex.Response; } Stream webStream = response.GetResponseStream(); if (webStream == null) { throw new Exception("Network error"); } int statsCode = (int)response.StatusCode; resultReader = new StreamReader(webStream, Encoding.UTF8); string responseContent = resultReader.ReadToEnd(); //如果http请求响应非200，则异常 if (statsCode != 200) { throw new Exception(statsCode.ToString()); } return responseContent; } catch (Exception e) { throw e; } finally { if (response != null) response.Close(); if (resultReader != null) resultReader.Close(); } }
二、WebClient
支持.net 4.5 以下。主要用于从特定的URI请求文件，WebClient很轻量级的访问Internet资源的类，在指定uri后可以发送和接受数据。WebClient提供了 DownLoadData,DownLoadFile,UploadData,UploadFile 等方法，同时通过了这些方法对应的异步方法，通过WebClient可以很方便地上传和下载文件。
上传文件
{ /*
这个方法会在对应的目录创建test.txt 文件
*/
WebClient webClient = new WebClient();
Stream stream = webClient.OpenRead("http://localhost:5743/file/test.txt");
StreamWriter writer = new StreamWriter(stream);
writer.WriteLine("哈哈哈哈哈哈");
writer.Flush();
writer.Close();
}
{ /*
UploadFile把文件上传到指定目录
*/
WebClient webClient = new WebClient();
string file = @"d:download emp.zip";
byte[] responseArray = webClient.UploadFile("http://localhost:5743/rss/temp.zip", file);
Console.WriteLine(Encoding.ASCII.GetString(responseArray));
}
{
/*
UploadData数据缓冲区上传到指定目录
*/
WebClient webClient = new WebClient
{
Encoding = Encoding.UTF8
};
string file = @"d:download emp.jpg";
FileStream fs = new FileStream(file, FileMode.Open, FileAccess.Read);
byte[] btye = new byte[fs.Length];
fs.Read(btye, 0, btye.Length);
byte[] responseArray = webClient.UploadData("http://localhost:5743/rss/temp.jpg", btye);
Console.WriteLine(Encoding.UTF8.GetString(responseArray));
}
下载文件
{ /*
DownloadData读取文件为byte[] 例如直接读取图片,文本
DownloadString 直接读取文件为string,除了读文本,可以当做Get方法,直接读取html代码
DownloadFile 下载文件到指定目录
*/
WebClient webClient = new WebClient();
byte[] bytes = webClient.DownloadData("http://localhost:5743/rss/temp.zip");
string result = webClient.DownloadString("http://localhost:5743/rss/temp.zip");
webClient.DownloadFile("http://localhost:5743/rss/temp.zip", @"d:download emp.zip");
}
三、HttpClient
.net 4.5 开始提供基本类，用于发送 HTTP 请求和接收来自通过 URI 确认的资源的 HTTP 响应。Get方式，HttpClient提供 GetAsync,GetStringAsync,GetStreamAsync,GetStringAsync 方法。相对于Post 则要提供派生自httpContent类作为请求参数
Task.Run(async () => { HttpClient httpClient = new HttpClient(); var parameter = new List<KeyValuePair<string, string>>() { new KeyValuePair<string, string>("userName","haosit"), new KeyValuePair<string, string>("password","haosit123") }; FormUrlEncodedContent content = new FormUrlEncodedContent(parameter); HttpResponseMessage response = await httpClient.PostAsync("http://localhost:5531", content); response.EnsureSuccessStatusCode();//如果响应错误则抛出异常 string result = await response.Content.ReadAsStringAsync(); });
3.1 HttpContent 分别是：
1. FormUrlEncodedContent 使用应用程序/x-www 的窗体的 urlencoded MIME 类型编码的名称/值元组的 HTTP 内容。例如：application/x-www-form-urlencoded
2. MultipartContent 获取序列化使用多部分 HTTP 内容 / * 内容类型规范。例如：multipart/mixed; boundary="aba404d0-4a56-4cb7-be14-f0fb32b02030"
3. MultipartFormDataContent 的使用 multipart/form-data MIME 类型编码 HTTP 内容。例如：multipart/form-data; boundary="755ab5e6-1263-4e19-8b8b-da60f9ce78c2"
4. StringContent -基于 HTTP 内容字符串
5. StreamContent -基于 HTTP 内容流
6. ByteArrayContent -基于 HTTP 内容的字节数组
3.2 StringContent
StringContent 可以定义Content-Type
Dictionary<string, string> parameter = new Dictionary<string, string>() { { "username","haosit"}, { "password","haosit123"} }; var http = new HttpClient(); string body = JsonConvert.SerializeObject(parameter); var content = new StringContent(body, Encoding.UTF8, "application/json"); http.PostAsync("http://localhost:5531", content);
3.3 StreamContent 和 ByteArrayContent ：httpClient 携带文件
StreamContent，ByteArrayContent 可以作为MultipartContent，MultipartFormDataContent 携带的文件参数
var multipartFormDataContent = new MultipartFormDataContent(); var parameter = new[] { new KeyValuePair<string, string>("a", "3"), new KeyValuePair<string, string>("c", "2"), new KeyValuePair<string, string>("d", "2") }; var http = new HttpClient(); foreach (var item in parameter) { multipartFormDataContent.Add(new StringContent(item.Value),item.Key); } multipartFormDataContent.Add(new ByteArrayContent(File.ReadAllBytes(@"D: est.jpg")),"test","test.jpg"); http.PostAsync("http://localhost:5531", multipartFormDataContent);
3.4 携带cookie
handler.UseCookies=true(默认为true)，默认的会自己带上cookies
{ var handler = new HttpClientHandler() { UseCookies = true }; var http = new HttpClient(handler); }