[HttpGet]

        public HttpResponseMessage ExportPdf(string id)

        {

            string pdfName = "";
　　　　　　　//id 查询条件，根据实际情况修改即可
　　　　　　　//pdfName 例如download.pdf

            byte[] pdfData= _policyGapManagerService.ExportPdf(id, out pdfName);//获得pdf字节

            var result = new HttpResponseMessage(HttpStatusCode.OK)

            {

                Content = new ByteArrayContent(pdfData)

            };

            result.Content.Headers.ContentDisposition =

                new ContentDispositionHeaderValue("attachment")

                {

                    FileName = pdfName

                };

            result.Content.Headers.ContentType =new MediaTypeHeaderValue("application/pdf");

            return result;

        }

#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, , 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, , buffer1.Length)) > )

                {

                    stmMemory.Write(buffer1, , 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[];

                    int n = ;

                    while (n > )

                    {

                        //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, , );

                        fs.Write(bytes, , 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

/// <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 = ;

                        byte[] bytes = new byte[];

                        readCout = s.Read(bytes, , );

                        while (readCout > )

                        {

                            fs.Write(bytes, , readCout);

                            readCout = s.Read(bytes, , );

                        }

                    }

                }

                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 > )

                        {

                            fileList.Add(sb.ToString());

                            sb.Clear();

                        }

                        else

                        {

                            break;

                        }

                    } while (true);

                }

                return fileList.ToArray();

            }

            catch (Exception)

            {

                 return null;

            }

        }