net mvc 利用NPOI导入导出excel

1、导出Excel ：
首先引用NPOI包（Action一定要用FileResult）

    /// <summary>
            /// 批量导出需要导出的列表
            /// </summary>
            /// <returns></returns>
            public FileResult ExportStu2()
            {
                //获取list数据
                var checkList = (from oc in db.OrganizeCustoms
                                join o in db.Organizes.DefaultIfEmpty() on oc.custom_id equals o.id
                                where oc.organize_id ==
                                select new
                                {
                                    customer_id = o.id,
                                    customer_name = o.name
                                }).ToList();  

                //创建Excel文件的对象
                NPOI.HSSF.UserModel.HSSFWorkbook book = new NPOI.HSSF.UserModel.HSSFWorkbook();
                //添加一个sheet
                NPOI.SS.UserModel.ISheet sheet1 = book.CreateSheet("Sheet1");  

                //貌似这里可以设置各种样式字体颜色背景等，但是不是很方便，这里就不设置了  

                //给sheet1添加第一行的头部标题
                NPOI.SS.UserModel.IRow row1 = sheet1.CreateRow();
                row1.CreateCell().SetCellValue("编号");
                row1.CreateCell().SetCellValue("姓名");
                //....N行  

                //将数据逐步写入sheet1各个行
                for (int i = ; i < checkList.Count; i++)
                {
                    NPOI.SS.UserModel.IRow rowtemp = sheet1.CreateRow(i + );
                    rowtemp.CreateCell().SetCellValue(checkList[i].customer_id.ToString());
                    rowtemp.CreateCell().SetCellValue(checkList[i].customer_name.ToString());
                    //....N行
                }
                // 写入到客户端
                System.IO.MemoryStream ms = new System.IO.MemoryStream();
                book.Write(ms);
                ms.Seek(, SeekOrigin.Begin);
                DateTime dt = DateTime.Now;
                string dateTime = dt.ToString("yyMMddHHmmssfff");
                string fileName = "查询结果" + dateTime + ".xls";
                return File(ms, "application/vnd.ms-excel", fileName);
            }  

前台直接写就可实现：

@Html.ActionLink("点击导出Excel", "ExportStu2")  

这里有一篇专门介绍设置样式的文章：
http://www.cnblogs.com/puzi0315/p/3265958.html
http://blog.csdn.net/xhccom/article/details/7687264
http://blog.csdn.net/bestreally/article/details/23257851

2、导入Excel：

首先说一些前台吧，mvc上传注意必须加 new { enctype = "multipart/form-data" }

    <td>
        @using (@Html.BeginForm("ImportStu", "ProSchool", FormMethod.Post, new { enctype = "multipart/form-data" }))
        {
            <text>选择上传文件：（工作表名为“Sheet1”，“电脑号”在A1单元格。）</text>
            <input name="file" type="file" id="file" />
            <input type="submit" name="Upload" value="批量导入第一批名册" />
        }
    </td>  

后台实现：只传路径得出DataTable：

    /// <summary>
        /// Excel导入
        /// </summary>
        /// <param name="filePath"></param>
        /// <returns></returns>
        public DataTable ImportExcelFile(string filePath)
        {
          HSSFWorkbook hssfworkbook;
          #region//初始化信息
          try
          {
            using (FileStream file = new FileStream(filePath, FileMode.Open, FileAccess.Read))
            {
              hssfworkbook = new HSSFWorkbook(file);
            }
          }
          catch (Exception e)
          {
            throw e;
          }
          #endregion  

          using (NPOI.SS.UserModel.ISheet sheet = hssfworkbook.GetSheetAt())
          {
            DataTable table = new DataTable();
            IRow headerRow = sheet.GetRow();//第一行为标题行
            int cellCount = headerRow.LastCellNum;//LastCellNum = PhysicalNumberOfCells
            int rowCount = sheet.LastRowNum;//LastRowNum = PhysicalNumberOfRows - 1  

            //handling header.
            for (int i = headerRow.FirstCellNum; i < cellCount; i++)
            {
              DataColumn column = new DataColumn(headerRow.GetCell(i).StringCellValue);
              table.Columns.Add(column);
            }
            for (int i = (sheet.FirstRowNum + ); i <= rowCount; i++)
            {
              IRow row = sheet.GetRow(i);
              DataRow dataRow = table.NewRow();  

              if (row != null)
              {
                for (int j = row.FirstCellNum; j < cellCount; j++)
                {
                  if (row.GetCell(j) != null)
                    dataRow[j] = GetCellValue(row.GetCell(j));
                }
              }
              table.Rows.Add(dataRow);
            }
            return table;
          }
        }  

补充一个类：

    /// <summary>
        /// 根据Excel列类型获取列的值
        /// </summary>
        /// <param name="cell">Excel列</param>
        /// <returns></returns>
        private static string GetCellValue(ICell cell)
        {
          if (cell == null){ return string.Empty; }
          switch (cell.CellType)
          {
            case CellType.BLANK:
              return string.Empty;
            case CellType.BOOLEAN:
              return cell.BooleanCellValue.ToString();
            case CellType.ERROR:
              return cell.ErrorCellValue.ToString();
            case CellType.NUMERIC:
            case CellType.Unknown:
            default:
              return cell.ToString();//This is a trick to get the correct value of the cell. NumericCellValue will return a numeric value no matter the cell value is a date or a number
            case CellType.STRING:
              return cell.StringCellValue;
            case CellType.FORMULA:
              try
              {
                HSSFFormulaEvaluator e = new HSSFFormulaEvaluator(cell.Sheet.Workbook);
                e.EvaluateInCell(cell);
                return cell.ToString();
              }
              catch
              {
                return cell.NumericCellValue.ToString();
              }
          }
        }  

得到DataTable后，就想怎么操作就怎么操作了。