C#HttpWebRequest常用请求方式

在C#中使用HttpWebRequest类是用于发送HTTP请求的类，它属于System.Net命名空间。通过HttpWebRequest，你可以使用不同的请求方法（例如GET、POST、PUT、DELETE等）来与Web服务器进行交互。

1. GET请求

GET请求通常用于请求服务器上的数据，不修改服务器上的资源。

引用

using System.IO;
using System.Net;
using System.Threading.Tasks;

//直接返回字符串
public static string HttpGet(string url)
{
	Encoding encoding = Encoding.UTF8;
	HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
	request.Method = "GET";
	request.Accept = "text/html, application/xhtml+xml, */*";
	request.ContentType = "application/json";
	HttpWebResponse response = (HttpWebResponse)request.GetResponse();
	using (StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8))
	{
		return reader.ReadToEnd();
	}
}

// 直接读取文件流
public static string HttpGet(string url)
{
    HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
    req.Method = "Get";
    try
    {
        using (WebResponse wr = req.GetResponse())
        {
            HttpWebResponse response = wr as HttpWebResponse;
            Stream stream = response.GetResponseStream();
            //读取到内存
            MemoryStream ms = new MemoryStream();
            byte[] buffer = new byte[1024];
            while (true)
            {
                int sz = stream.Read(buffer, 0, 1024);
                if (sz == 0) break;
                ms.Write(buffer, 0, sz);
            }
            string content = Convert.ToBase64String(ms.ToArray());
            return content;
        }
    }
    catch (Exception ex)
    {
        return null;
    }
}

2. POST请求

POST请求通常用于向服务器提交数据，如表单数据或JSON数据。

application/json

//Post
public static string HttpPost(string url, string body)
{
	Encoding encoding = Encoding.UTF8;
	HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
	request.Method = "POST";
	request.Accept = "text/html, application/xhtml+xml, */*";
	request.ContentType = "application/json";
	byte[] buffer = encoding.GetBytes(body);
	request.ContentLength = buffer.Length;
	request.GetRequestStream().Write(buffer, 0, buffer.Length);
	HttpWebResponse response = (HttpWebResponse)request.GetResponse();
	using (StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8))
	{
		return reader.ReadToEnd();
	}
}

application/x-www-form-urlencoded

public static string PostUrlFormUrlencoded(string url, string postData)
{
    string result = "";
    try
    {
        HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);


        req.Method = "POST";


        req.ContentType = "application/x-www-form-urlencoded";


        //req.Timeout = 8000;//请求超时时间


        byte[] data = Encoding.UTF8.GetBytes(postData);


        req.ContentLength = data.Length;


        using (Stream reqStream = req.GetRequestStream())
        {
            reqStream.Write(data, 0, data.Length);


            reqStream.Close();
        }


        HttpWebResponse resp = (HttpWebResponse)req.GetResponse();


        Stream stream = resp.GetResponseStream();


        //获取响应内容
        using (StreamReader reader = new StreamReader(stream, Encoding.UTF8))
        {
            result = reader.ReadToEnd();
        }
    }
    catch (Exception e)
    {
        Console.WriteLine("发送请求出错：" + e.Message);
    }


    return result;
}

multipart/form-data

public static string HttpPost(string url, NameValueCollection kVDatas = null, JObject headers = null,
    string method = WebRequestMethods.Http.Post, int timeOut = -1)
{
    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)WebRequest.Create(url);
        request.ContentType = "multipart/form-data; boundary=" + boundary;
        request.Method = "POST";
        request.KeepAlive = true;
        request.Timeout = timeOut;
        if (headers != null)
        {
            IEnumerable properties = headers.Properties();
            foreach (JProperty item in properties)
            {
                request.Headers.Add(item.Name, item.Value.ToString());
            }
        }


        CredentialCache credentialCache = new CredentialCache
        {
            { new Uri(url), "Basic", new NetworkCredential("member", "secret") }
        };
        request.Credentials = credentialCache;


        request.ServicePoint.Expect100Continue = false;
        using (Stream stream = request.GetRequestStream())
        {
            string formdataTemplate = "Content-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}";
            if (kVDatas != null)
            {
                foreach (string key in kVDatas.Keys)
                {
                    stream.Write(boundarybytes, 0, boundarybytes.Length);
                    string formitem = string.Format(formdataTemplate, key, kVDatas[key]);
                    byte[] formitembytes = Encoding.GetEncoding("UTF-8").GetBytes(formitem);
                    stream.Write(formitembytes, 0, formitembytes.Length);
                }
            }
            stream.Write(endbytes, 0, endbytes.Length);
        }
        HttpWebResponse response = (HttpWebResponse)request.GetResponse();
        using (StreamReader stream = new StreamReader(response.GetResponseStream()))
        {
            return stream.ReadToEnd();
        }


    }
    catch (Exception e)
    {


        Console.WriteLine(e.Message);
        return e.Message;
    }
}

上传文件

public static string HttpUploadFile(string url, string filePath, string fileName, string paramName, string contentType,
    NameValueCollection nameValueCollection)
{
    string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x");
    byte[] boundarybytes = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");
    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
    request.ContentType = "multipart/form-data; boundary=" + boundary;
    request.Method = "POST";
    request.KeepAlive = true;
    request.Credentials = CredentialCache.DefaultCredentials;
    Stream requestStream = request.GetRequestStream();
    string formdataTemplate = "Content-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}";
    foreach (string key in nameValueCollection.Keys)
    {
        requestStream.Write(boundarybytes, 0, boundarybytes.Length);
        string formitem = string.Format(formdataTemplate, key, nameValueCollection[key]);
        byte[] formitembytes = System.Text.Encoding.UTF8.GetBytes(formitem);
        requestStream.Write(formitembytes, 0, formitembytes.Length);
    }
    requestStream.Write(boundarybytes, 0, boundarybytes.Length);
    string header = string.Format("Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\nContent-Type: {2}\r\n\r\n", paramName, fileName, contentType);
    byte[] headerbytes = Encoding.UTF8.GetBytes(header);
    requestStream.Write(headerbytes, 0, headerbytes.Length);
    FileStream fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read);
    byte[] buffer = new byte[4096];
    int bytesRead = 0;
    while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)
    {
        requestStream.Write(buffer, 0, bytesRead);
    }
    fileStream.Close();
    byte[] trailer = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "--\r\n");
    requestStream.Write(trailer, 0, trailer.Length);
    requestStream.Close();
    WebResponse webResponse = null;
    try
    {
        webResponse = request.GetResponse();
        Stream responseStream = webResponse.GetResponseStream();
        StreamReader streamReader = new StreamReader(responseStream);
        string result = streamReader.ReadToEnd();
        return result;
    }
    catch (Exception ex)
    {
        if (webResponse != null)
        {
            webResponse.Close();
            webResponse = null;
        }
        return null;
    }
    finally
    {
        request = null;
    }
}

3. PUT请求

PUT请求用于上传文件或修改服务器上的资源。

public static void HttpPUT()
{
	HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://example.com/api/data");
	request.Method = "PUT";
	request.ContentType = "application/json"; // 或者其他适当的MIME类型，如 "text/xml" 或 "image/jpeg" 等


	using (var postData = new StreamWriter(request.GetRequestStream()))
	{
		postData.Write(JsonConvert.SerializeObject(new { key1 = "value1", key2 = "value2" })); // 发送JSON数据示例
	}


	using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
	{
		using (Stream responseStream = response.GetResponseStream())
		{
			using (StreamReader reader = new StreamReader(responseStream))
			{
				string responseText = reader.ReadToEnd();
				Console.WriteLine(responseText);
			}
		}
	}
}

4. DELETE请求

DELETE请求用于请求删除指定的资源。

public static void HttpDELETE()
{
	HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://example.com/api/data/123"); // 假设删除ID为123的资源
	request.Method = "DELETE";
	using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
	{
		Console.WriteLine("Resource deleted with status: " + response.StatusCode);
	}
}

C# HttpClient四种常用请求数据格式

C#调用WebApi请求常用的两种方式