HttpWebRequest 上传文件

最新推荐文章于 2022-02-10 08:00:00 发布

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最新推荐文章于 2022-02-10 08:00:00 发布

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CC 4.0 BY-SA版权

原文链接：http://www.cnblogs.com/loujady/archive/2011/09/13/2174695.html

本文详细介绍了使用C#语言通过HTTP POST请求上传文件至服务器的方法，包括初始化请求、设置请求头、构造请求参数和文件数据、发送请求及接收响应等关键步骤。同时，文中还涉及了如何利用内存流处理文件上传过程，确保了上传过程的高效性和安全性。

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  //边界
            string boundary = DateTime.Now.Ticks.ToString("x");
            HttpWebRequest uploadRequest = (HttpWebRequest)WebRequest.Create(url);//url为上传的地址
            uploadRequest.ContentType = "multipart/form-data; boundary=" + boundary;
            uploadRequest.Method = "POST";
            uploadRequest.Accept = "*/*";
            uploadRequest.KeepAlive = true;
            uploadRequest.Headers.Add("Accept-Language", "zh-cn");
            uploadRequest.Headers.Add("Accept-Encoding", "gzip, deflate");
            uploadRequest.Credentials = System.Net.CredentialCache.DefaultCredentials;
            uploadRequest.Headers["Cookie"] = cookies;//上传文件时需要的cookies

            WebResponse reponse;
            //创建一个内存流
            Stream memStream = new MemoryStream();

            //确定上传的文件路径
            if (!String.IsNullOrEmpty(file))
            {
                boundary = "--" + boundary;

                //添加上传文件参数格式边界
                string paramFormat = boundary + "\r\nContent-Disposition: form-data; name=\"{0}\";\r\n\r\n{1}\r\n";
                NameValueCollection param = new NameValueCollection();
                param.Add("fname", Guid.NewGuid().ToString() + Path.GetExtension(file));

                //写上参数
                foreach (string key in param.Keys)
                {
                    string formitem = string.Format(paramFormat, key, param[key]);
                    byte[] formitembytes = System.Text.Encoding.UTF8.GetBytes(formitem);
                    memStream.Write(formitembytes, 0, formitembytes.Length);
                }

                //添加上传文件数据格式边界
                string dataFormat = boundary + "\r\nContent-Disposition: form-data; name=\"{0}\";filename=\"{1}\"\r\nContent-Type:application/octet-stream\r\n\r\n";
                string header = string.Format(dataFormat, "Filedata", Path.GetFileName(file));
                byte[] headerbytes = System.Text.Encoding.UTF8.GetBytes(header);
                memStream.Write(headerbytes, 0, headerbytes.Length);

                //获取文件内容
                FileStream fileStream = new FileStream(file, FileMode.Open, FileAccess.Read);
                byte[] buffer = new byte[1024];
                int bytesRead = 0;

                //将文件内容写进内存流
                while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)
                {
                    memStream.Write(buffer, 0, bytesRead);
                }
                fileStream.Close();

                //添加文件结束边界
                byte[] boundarybytes = System.Text.Encoding.UTF8.GetBytes("\r\n\n" + boundary + "\r\nContent-Disposition: form-data; name=\"Upload\"\r\n\nSubmit Query\r\n" + boundary + "--");
                memStream.Write(boundarybytes, 0, boundarybytes.Length);

                //设置请求长度
                uploadRequest.ContentLength = memStream.Length;
                //获取请求写入流
                Stream requestStream = uploadRequest.GetRequestStream();


                //将内存流数据读取位置归零
                memStream.Position = 0;
                byte[] tempBuffer = new byte[memStream.Length];
                memStream.Read(tempBuffer, 0, tempBuffer.Length);
                memStream.Close();

                //将内存流中的buffer写入到请求写入流
                requestStream.Write(tempBuffer, 0, tempBuffer.Length);
                requestStream.Close();
            }

            //获取到上传请求的响应
            reponse = uploadRequest.GetResponse();

作者：Louja
出处：http://loujady.cnblogs.com
本文版权归作者和博客园共有，欢迎转载，但未经作者同意必须保留此声明，且在文章页面给出原文连接，否则保留追究法律责任的权利。

转载于:https://www.cnblogs.com/loujady/archive/2011/09/13/2174695.html