将HtmlTable内容导出到Excel，使用NPOI组件

      /// <summary>
        /// 将DataTable导出到Excel
        /// </summary>
        /// <param name="htmlTable">html表格内容</param>
        /// <param name="fileName">仅文件名（非路径）</param>
        /// <returns>返回Excel文件绝对路径</returns>
        public static string ExportHtmlTableToExcel(string htmlTable, string fileName)
        {
            string result;
            try
            {
                #region 第一步：将HtmlTable转换为DataTable
                htmlTable = htmlTable.Replace("\"", "'");
                var trReg = new Regex(pattern: @"(?<=(<[t|T][r|R]))[\s\S]*?(?=(</[t|T][r|R]>))");
                var trMatchCollection = trReg.Matches(htmlTable);
                DataTable dt = new DataTable("data");
                for (int i = 0; i < trMatchCollection.Count; i++)
                {
                    var row = "<tr " + trMatchCollection[i].ToString().Trim() + "</tr>";
                    var tdReg = new Regex(pattern: @"(?<=(<[t|T][d|D|h|H]))[\s\S]*?(?=(</[t|T][d|D|h|H]>))");
                    var tdMatchCollection = tdReg.Matches(row);
                    if (i == 0)
                    {
                        foreach (var rd in tdMatchCollection)
                        {
                            var tdValue = RemoveHtml("<td " + rd.ToString().Trim() + "</td>");
                            DataColumn dc = new DataColumn(tdValue);
                            dt.Columns.Add(dc);
                        }
                    }
                    if (i > 0)
                    {
                        DataRow dr = dt.NewRow();
                        for (int j = 0; j < tdMatchCollection.Count; j++)
                        {
                            var tdValue = RemoveHtml("<td " + tdMatchCollection[j].ToString().Trim() + "</td>");
                            dr[j] = tdValue;
                        }
                        dt.Rows.Add(dr);
                    }
                }
                #endregion

                #region 第二步：将DataTable导出到Excel
                result = "ok_" + ExportDataSetToExcel(dt, fileName);
                #endregion
            }
            catch (Exception ex)
            {
                result = "err_" + ex.Message;
            }
            return result;
        }

        /// <summary>
        /// 将DataTable导出到Excel
        /// </summary>
        /// <param name="dt">DataTable</param>
        /// <param name="fileName">仅文件名（非路径）</param>
        /// <returns>返回Excel文件绝对路径</returns>
        public static string ExportDataSetToExcel(DataTable dt, string fileName)
        {
            #region 表头
            HSSFWorkbook hssfworkbook = new HSSFWorkbook();
            NPOI.SS.UserModel.Sheet hssfSheet = hssfworkbook.CreateSheet(fileName);
            hssfSheet.DefaultColumnWidth = 13;
            hssfSheet.SetColumnWidth(0, 25 * 256);
            hssfSheet.SetColumnWidth(3, 20 * 256);
            // 表头
            NPOI.SS.UserModel.Row tagRow = hssfSheet.CreateRow(0);
            tagRow.Height = 22 * 20;

            // 标题样式
            NPOI.SS.UserModel.CellStyle cellStyle = hssfworkbook.CreateCellStyle();
            cellStyle.Alignment = HorizontalAlignment.CENTER;
            cellStyle.VerticalAlignment = VerticalAlignment.CENTER;
            cellStyle.BorderBottom = CellBorderType.THIN;
            cellStyle.BorderBottom = CellBorderType.THIN;
            cellStyle.BottomBorderColor = NPOI.HSSF.Util.HSSFColor.BLACK.index;
            cellStyle.BorderLeft = CellBorderType.THIN;
            cellStyle.LeftBorderColor = NPOI.HSSF.Util.HSSFColor.BLACK.index;
            cellStyle.BorderRight = CellBorderType.THIN;
            cellStyle.RightBorderColor = NPOI.HSSF.Util.HSSFColor.BLACK.index;
            cellStyle.BorderTop = CellBorderType.THIN;
            cellStyle.TopBorderColor = NPOI.HSSF.Util.HSSFColor.BLACK.index;

            int colIndex;
            for (colIndex = 0; colIndex < dt.Columns.Count; colIndex++)
            {
                tagRow.CreateCell(colIndex).SetCellValue(dt.Columns[colIndex].ColumnName);
                tagRow.GetCell(colIndex).CellStyle = cellStyle;
            }
            #endregion
            #region 表数据
            // 表数据
            for (int k = 0; k < dt.Rows.Count; k++)
            {
                DataRow dr = dt.Rows[k];
                NPOI.SS.UserModel.Row row = hssfSheet.CreateRow(k + 1);
                for (int i = 0; i < dt.Columns.Count; i++)
                {
                    row.CreateCell(i).SetCellValue(dr[i].ToString());
                    row.GetCell(i).CellStyle = cellStyle;
                }
            }
            #endregion
            FileStream file = new FileStream(HttpContext.Current.Request.PhysicalApplicationPath + "Temp/" + fileName + ".xls", FileMode.Create);
            hssfworkbook.Write(file);
            file.Close();
            var basePath = VirtualPathUtility.AppendTrailingSlash(HttpContext.Current.Request.ApplicationPath);
            return (basePath + "Temp/" + fileName + ".xls");
        }

        /// <summary>
        ///     去除HTML标记
        /// </summary>
        /// <param name="htmlstring"></param>
        /// <returns>已经去除后的文字</returns>
        public static string RemoveHtml(string htmlstring)
        {
            //删除脚本
            htmlstring =
                Regex.Replace(htmlstring, @"<script[^>]*?>.*?</script>",
                              "", RegexOptions.IgnoreCase);
            //删除HTML
            htmlstring = Regex.Replace(htmlstring, @"<(.[^>]*)>", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"([\r\n])[\s]+", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"-->", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"<!--.*", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"&(quot|#34);", "\"", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"&(amp|#38);", "&", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"&(lt|#60);", "<", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"&(gt|#62);", ">", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"&(nbsp|#160);", "   ", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"&(iexcl|#161);", "\xa1", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"&(cent|#162);", "\xa2", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"&(pound|#163);", "\xa3", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"&(copy|#169);", "\xa9", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"&#(\d+);", "", RegexOptions.IgnoreCase);

            htmlstring = htmlstring.Replace("<", "");
            htmlstring = htmlstring.Replace(">", "");
            htmlstring = htmlstring.Replace("\r\n", "");
            return htmlstring;
        }