c# asp.net NPOI 使用本地模板导出excel

using NPOI.HSSF.UserModel;  protected void btnExcel_Click(object sender, EventArgs e)        {            //将页面中的值放入excel模板中            string TempletFileName = Server.MapPath("Template/test.xls");            //导出文件              FileStream file = new FileStream(TempletFileName, FileMode.Open, FileAccess.Read);            HSSFWorkbook hssfworkbook = new HSSFWorkbook(file);            HSSFSheet ws = hssfworkbook.GetSheet("testSheet");            //添加或修改WorkSheet里的数据              //line 1            ws.GetRow(0).GetCell(0).SetCellValue("123");            ws.GetRow(0).GetCell(1).SetCellValue("Plan");              ws.ForceFormulaRecalculation = true;                    HttpContext.Current.Response.Clear();                    HttpContext.Current.Response.Buffer = false;                    HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.GetEncoding("UTF-8");                    HttpContext.Current.Response.ContentType = "application/vnd.ms-excel";                    HttpContext.Current.Response.AddHeader("Content-Type", "application/octet-stream");                    HttpContext.Current.Response.Charset = "UTF-8";                    //设置下载的Excel文件名                    HttpContext.Current.Response.AddHeader("Content-Disposition", string.Format("attachment;filename={0}", System.Web.HttpUtility.UrlEncode(filename + DateTime.Now.ToString("yyyyMMddhhmm") + ".xls", System.Text.Encoding.UTF8))); //文件名使用UTF-8编码                    //Clear方法删除所有缓存中的HTML输出。但此方法只删除Response显示输入信息，不删除Response头信息。以免影响导出数据的完整性。                    HttpContext.Current.Response.Clear();                    using (MemoryStream ms = new MemoryStream())                    {                        //将工作簿的内容放到内存流中                        hssfworkbook.Write(ms);                        //将内存流转换成字节数组发送到客户端                        HttpContext.Current.Response.BinaryWrite(ms.GetBuffer());                        HttpContext.Current.Response.End();                    }        }