Rest文件下载

 public void DownloadFile(string fileId)
        {
            //Stream fileStream = null;
            try
            {
                int fileID = Convert.ToInt32(fileId);
                string RelatePath = fileInfoBLL.GetRelatePath(fileID);
                string fileFullPath = filePath + "\\" + RelatePath;
                string fileName = fileInfoBLL.GetFileName(fileID);
                var response = HttpContext.Current.Response;
                response.Clear();
                response.Buffer = true;
                //fileName = System.Web.HttpUtility.UrlEncode(fileName, System.Text.Encoding.GetEncoding("UTF-8"));
                response.AppendHeader("Content-Disposition", "attachment;filename=" + fileName);
                response.ContentEncoding = System.Text.Encoding.UTF8;
                response.Charset = "UTF-8";
                response.WriteFile(fileFullPath);
            }
            catch (Exception ex)
            {
                ExceptionHandler.ExceptionHelper.Instance.HandleException(ex);
            }
        }

将字符串转换成指定编码格式：

  string fileName = System.Web.HttpUtility.UrlEncode("要转换的字符串", System.Text.Encoding.GetEncoding("UTF-8"));

2    string gbStr =  System.Text.Encoding.GetEncoding("gb2312").GetString(System.Text.Encoding.Default.GetBytes('xxx'));

另一种：

 private void DownloadFile(string fileName, string filePath)
        {
            try
            {
                if (!string.IsNullOrEmpty(filePath))
                {
                    if (string.IsNullOrEmpty(fileName))
                    {
                        fileName = filePath.Substring(filePath.LastIndexOf("\\") + 1);
                    }

                    context.Response.Clear();
                    context.Response.Buffer = true;
                    context.Response.AppendHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlPathEncode(fileName));
                    context.Response.ContentEncoding = System.Text.Encoding.UTF8;
                    context.Response.Charset = "UTF-8";
                    //context.Response.ContentType = "application/vnd.ms-excel";
                    context.Response.WriteFile(UploadFileSavePath + "\\" + filePath);
                }
            }
            catch (Exception ex)
            {
                ExceptionHelper.Instance.HandleException(ex);
                context.Response.Write("{\"bizSuccess\":false,\"msg\":\"下载文件时发生错误！\"}");
            }

            context.Response.Flush();
            context.Response.End();
        }

 利用WebOperationContext.Current.OutgoingResponse下载

public Stream DownloadFile(string token)
        {
            Stream fileStream = null;
            try
            {
                //FilesInfo filesInfo = m_FileDAL.Find<FilesInfo>(fileId);
                //string fileFullPath = filesInfo.FileUrl + filesInfo.FileName;
                //string fileFullPath = m_FileDAL.Find<FilesInfo>(fileId).FileUrl;
                //string fileFullPath = @"C:\Users\chen\Desktop\reader.txt";
                string fileFullPath = @"C:\Users\chen\Desktop\HSF第四次读后感.docx";
                //string fileName = "reader.txt";
                string fileName = "HSF第四次读后感.docx";
                fileStream = File.OpenRead(fileFullPath);
                var response = WebOperationContext.Current.OutgoingResponse;
                response.Headers.Add("Content-Disposition", "attachment;filename=" + HttpUtility.UrlPathEncode(fileName));
                response.ContentType = "application/octet-stream";               
                //var message = WebOperationContext.Current.CreateStreamResponse(fileStream, "application/octet-stream");
                //message.Headers.Add(System.ServiceModel.Channels.MessageHeader.CreateHeader("Content-Disposition", "", "attachment;filename=" + HttpUtility.UrlPathEncode(fileName)));               
             //response.Clear();
                  //response.Buffer = true;
                  //response.AppendHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlPathEncode(fileName));
                  //response.ContentEncoding = System.Text.Encoding.UTF8;
                  //response.Charset = "UTF-8";
               
                //result.Success = true;
                //result.ErrorMessage = string.Format("{0}下载成功！", fileId);
                //result.Data = fileStream;
            }
            catch (Exception ex)
            {
               
                //result.Success = false;
                //result.ErrorMessage = string.Format("{0}下载失败！", fileId);
                //result.Data = null;
            }

            return fileStream;
        }