/// <summary>
        /// 获取Excel数据
        /// </summary>
        /// <param name="fileName"></param>
        /// <returns></returns>
        public DataSet GetExcelData(string fileName,string workSheetName)
        {
            //连接字符串 HDR=Yes;查询数据包含数据行；"IMEX=1;"  将excel cell 內含值视为 text 
            string connString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=\""+fileName+"\";Extended Properties=\"Excel 8.0;HDR=Yes;IMEX=1\"";
            //查询字符串
            string sql = "select * from ["+workSheetName+"$] ";
            

            DataSet ds = new DataSet();
            OleDbConnection conn = new OleDbConnection(connString);
            try
            {
                OleDbDataAdapter adapter = new OleDbDataAdapter(sql, conn);
                conn.Open();

                adapter.Fill(ds);
            }
            catch (Exception ex)
            {
                throw new Exception("获取Excel数据出错:" + ex.Message.ToString());
            }
            finally
            {
                if (conn.State == ConnectionState.Open)
                {
                    conn.Close();
                }
            }

            return ds;
        }

Stopwatch watch = Stopwatch.StartNew();
            Console.WriteLine("------NPOI------");
            Console.WriteLine("{0}\tStart...", watch.ElapsedMilliseconds);
            var reader = DataSource.GetExportData(66);
            using (reader)
            {
                IWorkbook workbook = new XSSFWorkbook();
                ISheet sheet = workbook.CreateSheet();
                IRow headerRow = sheet.CreateRow(0);
                int cellCount = reader.FieldCount;
                string columnName = string.Empty;

                int rowIndex = 0;
                while (reader.Read())
                {
                    IRow dataRow = sheet.CreateRow(rowIndex);
                    for (int i = 0; i < cellCount; i++)
                    {
                        dataRow.CreateCell(i).SetCellValue(reader[i].ToString());
                    }
                    rowIndex++;
                    if (rowIndex % 10000 == 0)
                    {
                        Console.WriteLine("{0}\t{1}", watch.ElapsedMilliseconds, rowIndex);
                    }
                }
                MemoryStream ms = new MemoryStream();
                workbook.Write(ms);
                using (FileStream fs = new FileStream("NPOI.xlsx", FileMode.Create, FileAccess.Write))
                {
                    byte[] data = ms.ToArray();
                    fs.Write(data, 0, data.Length);
                    fs.Flush();
                }
            }
            Console.WriteLine("{0}\tEnd...", watch.ElapsedMilliseconds);
            watch.Stop();
以前写的测试代码，上百万条，这货压根吃不住。