private static Stream ExportDataTableToExcel(DataTable sourceTable, string sheetName)
        {
            HSSFWorkbook workbook = new HSSFWorkbook();
            MemoryStream ms = new MemoryStream();
            ISheet sheet = workbook.CreateSheet(sheetName);
            IRow headerRow = sheet.CreateRow(0);
            foreach (DataColumn column in sourceTable.Columns)
            {
                headerRow.CreateCell(column.Ordinal).SetCellValue(column.ColumnName);
            }
            int rowIndex = 1;

            foreach (DataRow row in sourceTable.Rows)
            {
                IRow dataRow = sheet.CreateRow(rowIndex);

                foreach (DataColumn column in sourceTable.Columns)
                {
                    dataRow.CreateCell(column.Ordinal).SetCellValue(row[column].ToString());
                }

                rowIndex++;
            }

            workbook.Write(ms);
            ms.Flush();
            ms.Position = 0;

            sheet = null;
            headerRow = null;
            workbook = null;

            return ms;
        }
        
        /// <summary>
         /// DataTable导出到Excel文件[winfrom]
         /// </summary>
         /// <param name="dtSource">源DataTable</param>
         /// <param name="strHeaderText">表头文本</param>
         /// <param name="strFileName">保存位置</param>
         public static void Export(DataTable dtSource, string strHeaderText, string strFileName)
         {
             using (MemoryStream ms = Export(dtSource, strHeaderText))
             {
                 using (FileStream fs = new FileStream(strFileName, FileMode.Create, FileAccess.Write))
                 {
                     byte[] data = ms.ToArray();
                     fs.Write(data, 0, data.Length);
                     fs.Flush();
                 }
             }
         }
        
        /// <summary>
        /// 由DataTable导出Excel[web]
        /// </summary>
        /// <param name="sourceTable">要导出数据的DataTable</param>
        /// <param name="fileName">指定Excel工作表名称</param>
        /// <returns>Excel工作表</returns>
        public static void ExportDataTableToExcel(DataTable sourceTable, string fileName, string sheetName)
        {
            try
            {
                MemoryStream ms = ExportDataTableToExcel(sourceTable, sheetName) as MemoryStream;
                HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.GetEncoding("utf-8");
                HttpContext.Current.Response.AppendHeader("Content-Disposition", "attachment;filename=" + System.Web.HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8));
                HttpContext.Current.Response.BinaryWrite(ms.ToArray());
                HttpContext.Current.Response.End();
                ms.Close();
                ms = null;
            }
            catch (Exception ex)
            {

                HttpContext.Current.Response.Write(ex);
            }
        }