【C#】.net 发送get/post请求

基础学习

/// <summary>
/// Http (GET/POST)
/// </summary>
/// <param name="url">请求URL</param>
/// <param name="parameters">请求参数</param>
/// <param name="method">请求方法</param>
/// <returns>响应内容</returns>
static string sendPost(string url, IDictionary<string, string> parameters, string method)
{
    if (method.ToLower() == "post")
    {
        HttpWebRequest req = null;
        HttpWebResponse rsp = null;
        System.IO.Stream reqStream = null;
        try
        {
            req = (HttpWebRequest)WebRequest.Create(url);
            req.Method = method;
            req.KeepAlive = false;
            req.ProtocolVersion = HttpVersion.Version10;
            req.Timeout = 5000;
            req.ContentType = "application/x-www-form-urlencoded;charset=utf-8";
            byte[] postData = Encoding.UTF8.GetBytes(BuildQuery(parameters, "utf8"));
            reqStream = req.GetRequestStream();
            reqStream.Write(postData, 0, postData.Length);
            rsp = (HttpWebResponse)req.GetResponse();
            Encoding encoding = Encoding.GetEncoding(rsp.CharacterSet);
            return GetResponseAsString(rsp, encoding);
        }
        catch (Exception ex)
        {
            return ex.Message;
        }
        finally
        {
            if (reqStream != null) reqStream.Close();
            if (rsp != null) rsp.Close();
        }
    }
    else
    {
        //创建请求
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url + "?" + BuildQuery(parameters, "utf8"));

        //GET请求
        request.Method = "GET";
        request.ReadWriteTimeout = 5000;
        request.ContentType = "text/html;charset=UTF-8";
        HttpWebResponse response = (HttpWebResponse)request.GetResponse();
        Stream myResponseStream = response.GetResponseStream();
        StreamReader myStreamReader = new StreamReader(myResponseStream, Encoding.GetEncoding("utf-8"));

        //返回内容
        string retString = myStreamReader.ReadToEnd();
        return retString;
    }
}

public HttpWebRequest GetWebRequest(string url, string method)
        {
            HttpWebRequest request = null;
            if (url.Contains("https"))
            {
                ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(this.CheckValidationResult);
                request = (HttpWebRequest)WebRequest.CreateDefault(new Uri(url));
            }
            else
            {
                request = (HttpWebRequest)WebRequest.Create(url);
            }
            request.ServicePoint.Expect100Continue = false;
            request.Method = method;
            request.KeepAlive = true;
            request.UserAgent = "stgp";
            return request;
        }

        /// <summary>
        /// 解决使用上面方法向同一个地址发送请求时会发生：基础连接已经关闭: 服务器关闭了本应保持活动状态的连接的问题
        /// </summary>
        /// <param name="url"></param>
        /// <param name="method"></param>
        /// <returns></returns>
        public HttpWebRequest GetWebRequestDotnetReference(string url, string method)
        {
            HttpWebRequest request = null;
            if (url.Contains("https"))
            {
                ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(this.CheckValidationResult);
                request = (HttpWebRequest)WebRequest.CreateDefault(new Uri(url));
            }
            else
            {
                request = (HttpWebRequest)WebRequest.Create(url);
            }

            request.Method = method;
            request.KeepAlive = false;//fase
            request.ProtocolVersion = HttpVersion.Version11;//Version11
            request.UserAgent = "stgp";
            return request;
        }

/// <summary>
/// 组装普通文本请求参数。
/// </summary>
/// <param name="parameters">Key-Value形式请求参数字典</param>
/// <returns>URL编码后的请求数据</returns>
static string BuildQuery(IDictionary<string, string> parameters, string encode)
{
    StringBuilder postData = new StringBuilder();
    bool hasParam = false;
    IEnumerator<KeyValuePair<string, string>> dem = parameters.GetEnumerator();
    while (dem.MoveNext())
    {
        string name = dem.Current.Key;
        string value = dem.Current.Value;
        // 忽略参数名或参数值为空的参数
        if (!string.IsNullOrEmpty(name))//&& !string.IsNullOrEmpty(value)
        {
            if (hasParam)
            {
                postData.Append("&");
            }
            postData.Append(name);
            postData.Append("=");
            if (encode == "gb2312")
            {
                postData.Append(HttpUtility.UrlEncode(value, Encoding.GetEncoding("gb2312")));
            }
            else if (encode == "utf8")
            {
                postData.Append(HttpUtility.UrlEncode(value, Encoding.UTF8));
            }
            else
            {
                postData.Append(value);
            }
            hasParam = true;
        }
    }
    return postData.ToString();
}

/// <summary>
/// 把响应流转换为文本。
/// </summary>
/// <param name="rsp">响应流对象</param>
/// <param name="encoding">编码方式</param>
/// <returns>响应文本</returns>
static string GetResponseAsString(HttpWebResponse rsp, Encoding encoding)
{
    System.IO.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.Close();
        if (stream != null) stream.Close();
        if (rsp != null) rsp.Close();
    }
}

string url = "http://www.example.com/api/exampleHandler.ashx";
var parameters = new Dictionary<string, string>();
parameters.Add("param1", "1"); 
parameters.Add("param2", "2"); 

string result = sendPost(url, parameters, "get");

进阶学习

一、读取本地图片文件，进行上传

public string DoPostWithFile(string url, IDictionary<string, string> textParams, List<string> filePathList, string charset = "utf-8")
        {
            string boundary = "-------" + DateTime.Now.Ticks.ToString("X"); // 随机分隔线

            HttpWebRequest req = GetWebRequestDotnetReference(url, "POST");
            req.ContentType = "multipart/form-data;charset=" + charset + ";boundary=" + boundary;

            System.IO.Stream reqStream = req.GetRequestStream();
            byte[] itemBoundaryBytes = Encoding.GetEncoding(charset).GetBytes("
--" + boundary + "
");
            byte[] endBoundaryBytes = Encoding.GetEncoding(charset).GetBytes("
--" + boundary + "--
");

            // 组装文本请求参数
            string textTemplate = "Content-Disposition:form-data;name="{0}"
Content-Type:text/plain

{1}";
            IEnumerator<KeyValuePair<string, string>> textEnum = textParams.GetEnumerator();
            while (textEnum.MoveNext())
            {
                string textEntry = string.Format(textTemplate, textEnum.Current.Key, textEnum.Current.Value);
                byte[] itemBytes = Encoding.GetEncoding(charset).GetBytes(textEntry);
                reqStream.Write(itemBoundaryBytes, 0, itemBoundaryBytes.Length);
                reqStream.Write(itemBytes, 0, itemBytes.Length);
            }

            // 组装文件请求参数
            #region 将文件转成二进制
            string fileName = string.Empty;
            byte[] fileContentByte = new byte[1024];

            string fileTemplate = "Content-Disposition:form-data;name="{0}";filename="{1}"

";
            foreach (string filePath in filePathList)
            {
                fileName = filePath.Substring(filePath.LastIndexOf("\") + 1);

                FileStream fs = new FileStream(filePath, FileMode.Open, FileAccess.Read);
                fileContentByte = new byte[fs.Length];
                fs.Read(fileContentByte, 0, Convert.ToInt32(fs.Length));
                fs.Close();

                string fileEntry = string.Format(fileTemplate, "images[]", fileName);
                byte[] itemBytesF = Encoding.GetEncoding(charset).GetBytes(fileEntry);
                reqStream.Write(itemBoundaryBytes, 0, itemBoundaryBytes.Length);
                reqStream.Write(itemBytesF, 0, itemBytesF.Length);
                reqStream.Write(fileContentByte, 0, fileContentByte.Length);
            }
            #endregion

            reqStream.Write(endBoundaryBytes, 0, endBoundaryBytes.Length);
            reqStream.Close();

            HttpWebResponse rsp = (HttpWebResponse)req.GetResponse();
            Encoding encoding = Encoding.GetEncoding(rsp.CharacterSet);
            return GetResponseAsString(rsp, encoding);
        }

string url = "http://www.example.com/api/exampleHandler.ashx";
var param = new Dictionary<string, string>();
 param.Add("param1", "1");
List<string> filePathList = new List<string>();
filePathList.Add(@"C:Userspic1.png");

string result = DoPostWithFile(url, param, filePathList);

二、读取网络上的图片文件，进行上传

public string DoPostWithNetFile(string url, IDictionary<string, string> textParams, List<string> filePathList, string charset = "utf-8")
        {
            string boundary = "-------" + DateTime.Now.Ticks.ToString("X"); // 随机分隔线

            //HttpWebRequest req = GetWebRequest(url, "POST");
            HttpWebRequest req = GetWebRequestDotnetReference(url, "POST");
            req.ContentType = "multipart/form-data;charset=" + charset + ";boundary=" + boundary;

            System.IO.Stream reqStream = req.GetRequestStream();
            byte[] itemBoundaryBytes = Encoding.GetEncoding(charset).GetBytes("
--" + boundary + "
");
            byte[] endBoundaryBytes = Encoding.GetEncoding(charset).GetBytes("
--" + boundary + "--
");

            // 组装文本请求参数
            string textTemplate = "Content-Disposition:form-data;name="{0}"
Content-Type:text/plain

{1}";
            IEnumerator<KeyValuePair<string, string>> textEnum = textParams.GetEnumerator();
            while (textEnum.MoveNext())
            {
                string textEntry = string.Format(textTemplate, textEnum.Current.Key, textEnum.Current.Value);
                byte[] itemBytes = Encoding.GetEncoding(charset).GetBytes(textEntry);
                reqStream.Write(itemBoundaryBytes, 0, itemBoundaryBytes.Length);
                reqStream.Write(itemBytes, 0, itemBytes.Length);
            }

            // 组装文件请求参数
            #region 将文件转成二进制
            string fileName = string.Empty;
            byte[] fileContentByte = new byte[1024];

            string fileTemplate = "Content-Disposition:form-data;name="{0}";filename="{1}"

";
            foreach (string filePath in filePathList)
            {
                fileName = filePath.Substring(filePath.LastIndexOf(@"/") + 1);



                HttpWebRequest imgRequest = (HttpWebRequest)WebRequest.Create(filePath);
                imgRequest.Method = "GET";
                using (HttpWebResponse imgResponse = imgRequest.GetResponse() as HttpWebResponse)
                {
                    if (imgResponse.StatusCode == HttpStatusCode.OK)
                    {
                        Stream rs = imgResponse.GetResponseStream();

                        MemoryStream ms = new MemoryStream();
                        const int bufferLen = 4096;
                        byte[] buffer = new byte[bufferLen];
                        int count = 0;
                        while ((count = rs.Read(buffer, 0, bufferLen)) > 0)
                        {
                            ms.Write(buffer, 0, count);
                        }


                        ms.Seek(0, SeekOrigin.Begin); int buffsize = (int)ms.Length; //rs.Length 此流不支持查找,先转为MemoryStream
                        fileContentByte = new byte[buffsize];

                        ms.Read(fileContentByte, 0, buffsize);
                        ms.Flush(); ms.Close();
                        rs.Flush(); rs.Close();
                    }
                }

                string fileEntry = string.Format(fileTemplate, "images[]", fileName);
                byte[] itemBytesF = Encoding.GetEncoding(charset).GetBytes(fileEntry);
                reqStream.Write(itemBoundaryBytes, 0, itemBoundaryBytes.Length);
                reqStream.Write(itemBytesF, 0, itemBytesF.Length);
                reqStream.Write(fileContentByte, 0, fileContentByte.Length);
            }
            #endregion

            reqStream.Write(endBoundaryBytes, 0, endBoundaryBytes.Length);
            reqStream.Close();

            HttpWebResponse rsp = (HttpWebResponse)req.GetResponse();
            Encoding encoding = Encoding.GetEncoding(rsp.CharacterSet);
            return GetResponseAsString(rsp, encoding);
        }

string url = "http://www.example.com/api/exampleHandler.ashx";
var param = new Dictionary<string, string>();
param.Add("param1", "1");
List<string> filePathList = new List<string>();
filePathList.Add(@"http://www.example.com/img/pic1.png");

string result = DoPostWithNetFile(url, param, filePathList);