C# 下载PDF文件（http与ftp）

1.下载http模式的pdf文件（以ASP.NET为例，将PDF存在项目的目录下，可以通过http直接打开项目下的pdf文件）

 #region 调用本地文件使用返回pdfbyte数组

        /// <summary>
        /// 调用本地文件使用返回pdfbyte数组
        /// </summary> /// <param name="srcPdfFile">‘D:\in2434341555551.pdf’</param> /// <returns></returns> public static byte[] GetSignaturePDFByte(string srcPdfFile) { using (FileStream fsRead = new FileStream(srcPdfFile, FileMode.Open, FileAccess.Read, FileShare.Read)) { int fsLen = (int)fsRead.Length; byte[] hebyte = new byte[fsLen]; fsRead.Read(hebyte, 0, hebyte.Length); return hebyte; } } #endregion 调用本地文件使用返回pdfbyte数组 #region 从网站上下载pdf，转化为字节流 /// <summary> /// 从网站上下载pdf，转化为字节流 /// </summary> /// <param name="srcPdfFile">文件地址：'https://******/group2/M00/00/04/wKj-mlpcoZ2IUbK5AACrpaV6k98AAAB6gAAAAAAAKu9562.pdf'</param> /// <returns></returns> public static Byte[] GetByteByRemoteURL(string srcPdfFile) { byte[] arraryByte; HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(srcPdfFile); req.Method = "GET"; using (WebResponse wr = req.GetResponse()) { StreamReader responseStream = new StreamReader(wr.GetResponseStream(), Encoding.UTF8); int length = (int)wr.ContentLength; byte[] bs = new byte[length]; HttpWebResponse response = wr as HttpWebResponse; Stream stream = response.GetResponseStream(); //读取到内存 MemoryStream stmMemory = new MemoryStream(); byte[] buffer1 = new byte[length]; int i; //将字节逐个放入到Byte 中 while ((i = stream.Read(buffer1, 0, buffer1.Length)) > 0) { stmMemory.Write(buffer1, 0, i); } arraryByte = stmMemory.ToArray(); stmMemory.Close(); } return arraryByte; } #endregion 从网站上下载pdf，转化为字节流 #region 从网站上下载文件，保存到其他路径 /// <summary> /// 从网站上下载文件，保存到其他路径 /// </summary> /// <param name="pdfFile">文件地址</param> /// <param name="saveLoadFile">保存文件路径：D:\12221.pdf</param> /// <returns></returns> public string SaveRemoteFile( string saveLoadFile , string pdfFile) { //bool flag = false; var f = saveLoadFile + Guid.NewGuid().ToString("D") + ".pdf"; Uri downUri = new Uri(pdfFile); //建立一个ＷＥＢ请求，返回HttpWebRequest对象 HttpWebRequest hwr = (HttpWebRequest)WebRequest.Create(downUri); //流对象使用完后自动关闭 using (Stream stream = hwr.GetResponse().GetResponseStream()) { //文件流，流信息读到文件流中，读完关闭 using (FileStream fs = File.Create(f)) { //建立字节组，并设置它的大小是多少字节 byte[] bytes = new byte[102400]; int n = 1; while (n > 0) { //一次从流中读多少字节，并把值赋给Ｎ，当读完后，Ｎ为０,并退出循环 n = stream.Read(bytes, 0, 10240); fs.Write(bytes, 0, n);　//将指定字节的流信息写入文件流中  } } } //return flag; //return _outPath + saveLoadFile; return f; } #endregion 从网站上下载文件，保存到其他路径

2.ftp模式的pdf文件

  /// <summary>
        /// 下载FTP文件。
        /// </summary> /// <param name="offsetPath">相对路径</param> /// <param name="fileName">文件名称</param> /// <returns>下载结果，本地文件路径</returns> public string DownLoad(string offsetPath,string fileName) { try { FtpWebRequest ftpWeb = (FtpWebRequest)WebRequest.Create(_ftpRootPath + offsetPath + fileName); ftpWeb.Method = WebRequestMethods.Ftp.DownloadFile; ftpWeb.UseBinary = true; var resp = ftpWeb.GetResponse(); using (FileStream fs = new FileStream(_outPath + fileName, FileMode.Create)) { using (var s = resp.GetResponseStream()) { if (s == null) { return "文件不存在!"; } int readCout = 0; byte[] bytes = new byte[1024]; readCout = s.Read(bytes, 0, 1024); while (readCout > 0) { fs.Write(bytes, 0, readCout); readCout = s.Read(bytes, 0, 1024); } } } resp.Close(); return _outPath + fileName; } catch (Exception e) { return e.Message; } } /// <summary> /// 判断文件是否存在 /// </summary> /// <param name="offsetPath"></param> /// <param name="fileName"></param> /// <returns></returns> public bool FileExists(string offsetPath, string fileName) { try { FtpWebRequest ftpWeb = (FtpWebRequest)WebRequest.Create(_ftpRootPath + offsetPath + fileName); ftpWeb.Method = WebRequestMethods.Ftp.DownloadFile; ftpWeb.UseBinary = true; var resp = (FtpWebResponse)ftpWeb.GetResponse(); resp.Close(); return true; } catch (Exception) { return false; } } /// <summary> /// 获取目录下所有文件 /// </summary> /// <returns></returns> public string[] Files(string offsetPath) { try { FtpWebRequest ftpWeb = (FtpWebRequest)WebRequest.Create(_ftpRootPath + offsetPath); ftpWeb.Method = WebRequestMethods.Ftp.ListDirectory; Stream stream = ftpWeb.GetResponse().GetResponseStream(); if (stream == null) { return null; } List<string> fileList = new List<string>(); using (StreamReader sr = new StreamReader(stream)) { StringBuilder sb = new StringBuilder(); do { sb.Append(sr.ReadLine()); if (sb.Length > 0) { fileList.Add(sb.ToString()); sb.Clear(); } else { break; } } while (true); } return fileList.ToArray(); } catch (Exception) { return null; } }