今天主要记录、分享 使用WebClient 下载/获取 文件的两种方式。
话不多说,放置代码。
第一种:使用 WebClient 自封装方法: DownloadFile(); 下载方便、直接。
/// <summary> /// 下载文件(WebClient.DownloadFile) /// </summary> /// <param name="downFileUrl">下载文件链接地址</param> /// <param name="savePath">保存路径</param> /// <returns></returns> public static string DownLoadFileByWebClientStatic(string downFileUrl, string savePath) { string result = string.Empty; try { WebClient wcClient = new WebClient(); wcClient.DownloadFile(downFileUrl, savePath); result = "下载成功"; } catch (WebException ex) { result = $"下载失败!Error={ ex.Message}"; } return result; } /// <summary> /// 下载文件(wcClient.DownloadFileAsync) /// </summary> /// <param name="downFileUrl">下载文件链接地址</param> /// <param name="savePath">保存路径</param> /// <returns></returns> public static string DownLoadFileMethod(string downFileUrl, string savePath) { string result = string.Empty; try { WebClient wcClient = new WebClient(); wcClient.DownloadDataCompleted += (t, s) => { result = "下载成功";//不会直接返回(无状态?) }; wcClient.DownloadFileAsync(new Uri(downFileUrl), savePath); } catch (WebException ex) { result = $"下载失败!Error={ ex.Message}"; } return result; }
第二种:使用读取文件流形式下载/获取文件。(自测通过)
/// <summary> /// 下载文件(Stream 形式处理) /// </summary> /// <param name="downFileUrl">下载文件链接地址</param> /// <param name="savePath">保存路径</param> /// <returns></returns> public static string DownLoadFileByWebClient(string downFileUrl, string savePath) { string result = string.Empty; try { WebClient wcClient = new WebClient(); WebRequest webReq = WebRequest.Create(downFileUrl); WebResponse webRes = webReq.GetResponse(); long fileLength = webRes.ContentLength; Stream srm = webRes.GetResponseStream(); StreamReader srmReader = new StreamReader(srm); byte[] bufferbyte = new byte[fileLength]; int allByte = (int)bufferbyte.Length; int startByte = 0; while (fileLength > 0) { int downByte = srm.Read(bufferbyte, startByte, allByte); if (downByte == 0) break; startByte += downByte; allByte -= downByte; } //检测保存文件所在目录是否存在 if (!File.Exists(savePath)) { string[] dirArray = savePath.Split(‘\\‘); string temp = string.Empty; for (int i = 0; i < dirArray.Length - 1; i++) { temp += dirArray[i].Trim() + "\\"; if (!Directory.Exists(temp)) Directory.CreateDirectory(temp); } } using (FileStream fsSave = new FileStream(savePath, FileMode.OpenOrCreate, FileAccess.Write)) { fsSave.Write(bufferbyte, 0, bufferbyte.Length); fsSave.Dispose(); } //与using 方法两者等同。 //FileStream fs = new FileStream(savePath, FileMode.OpenOrCreate, FileAccess.Write); //fs.Write(bufferbyte, 0, bufferbyte.Length); srm.Close(); srmReader.Close(); //fs.Close(); result = $"下载成功 path={savePath}"; } catch (WebException ex) { result = $"下载失败!Error={ ex.Message}"; } return result; }
第二种 通过文件流 下载,方法分支:(使用WebClient 的 OpenRead() 方式获取到Stream ,然后进行文件流读取,不知为何,自测失败,下载的文件无法正常打开)。 现在还没有找到合理解释,希望大家评论。
/// <summary> /// 下载文件 /// </summary> /// <param name="URLAddress">资源URL</param> /// <param name="saveBasePath">保存根目录/目录</param> /// <returns></returns> public string DownFileByStream(string URLAddress, string saveBasePath) { string result = string.Empty; try { WebClient client = new WebClient(); Stream str = client.OpenRead(URLAddress); StreamReader reader = new StreamReader(str); byte[] bytes = new byte[1024 * 1024];//自定义大小 1M int allybytes = (int)bytes.Length; int startbytes = 0; while (allybytes > 0) { int m = str.Read(bytes, startbytes, allybytes); //获取当前读取字节位置 if (m == 0) break; startbytes += m; allybytes -= m; } reader.Dispose(); str.Dispose(); string path = saveBasePath + System.IO.Path.GetFileName(URLAddress); FileStream fsWrite = new FileStream(path, FileMode.OpenOrCreate, FileAccess.Write); fsWrite.Write(bytes, 0, startbytes); fsWrite.Flush(); fsWrite.Close(); result = "下载成功!"; } catch (Exception ex) { result = "下载失败!" + ex.Message; } return result; }
如有不合理之处,欢迎指出。以上就是今天的记录;本文大部分内容都可以搜到,只是此处做了一个小整理。
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原文地址:https://www.cnblogs.com/skyheaving/p/12499629.html
时间: 2024-10-11 22:59:38