.NetMvc从http或本地下载pdf文件

1、帮助类

public static class PdfHelper
    {
        #region 从http链接下载
        public static void Download(string url, string name, System.Web.Mvc.Controller controller)
        {
            var bytes = GetByteByRemoteURL(url);
            controller.Response.Charset = "UTF-8";
            controller.Response.ContentType = "application/octet-stream";
            controller.Response.ContentEncoding = Encoding.Default;
            controller.Response.AddHeader("Content-Disposition", "attachment; filename=" + name.Replace(" ", "") + ".pdf");
            controller.Response.BinaryWrite(bytes);
            controller.Response.Flush();
            controller.Response.End();
        }
        #endregion

        #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

    }

2、调用方法

public ActionResult Down()
        {            
            PdfHelper.Download("http链接", "导出文件名字", this);
            return new EmptyResult();
        }

3、前端使用

 function Download() {
        location.href = "/xx/down";
    }