.Net 使用HttpWebRequest 和 HttpWebResponse 下载文件

最新推荐文章于 2023-05-13 14:29:38 发布

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本文介绍了如何在.Net中使用HttpWebRequest和HttpWebResponse类进行文件下载和POST请求上传文件。首先，通过创建HttpWebRequest对象并设置方法为GET，从指定URL获取文件数据流，然后将数据流写入本地文件。接着，展示了如何发起POST请求，通过设置请求方法为POST，打开请求流，并读取本地文件内容写入请求流完成文件上传。

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private void DownFile()
        {
            //获取文件路径
            string file_url = Request.QueryString["url"];
            if (file_url == null)
            {
                return;
            }

string ext_name = Path.GetExtension(file_url);
string file_name = Path.GetFileName(file_url);

            //组织存储路径和存储文件名
            string up_folder = System.Configuration.ConfigurationManager.AppSettings["hj_up_img"].ToString();
            up_folder = up_folder + HJ_DAL.ImgFolder._cls_space;
            string time_span = HJ_DAL.ImgFolder.GetTimeStamp();

            //获取远程文件的数据流
            FileStream fs = new FileStream(up_folder + time_span + ext_name, FileMode.Create);
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(file_url);
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            Stream stream = response.GetResponseStream();

int bufferSize = 2048;
byte[] bytes = new byte[bufferSize];

            try
            {
                int length = stream.Read(bytes, 0, bufferSize);

                while (length > 0)
                {
                    fs.Write(bytes, 0, length);
                    length = stream.Read(bytes, 0, bufferSize);
                }
                stream.Close();
                fs.Close();
                response.Close();
            }
            catch (Exception ex) {
                return;
            }
        }

post请求

protected void Button1_Click(object sender, EventArgs e)
        {
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://localhost:2588/http_file.aspx");
            request.Method = "post";
            request.KeepAlive = true;
           // request.ContentType = "application/x-www-form-urlencoded";

            string file = "img01.jpg";
            file=Server.MapPath(file);
            FileStream fileStream = new FileStream(file, FileMode.Open, FileAccess.Read);

request.ContentLength = fileStream.Length;
Stream rs = request.GetRequestStream();

            byte[] buffer = new byte[2048];
            int bytesRead = 0;
            while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)
            {
                rs.Write(buffer, 0, bytesRead);
            }
            fileStream.Close();

}