ajax模拟表单提交，后台使用npoi实现导入操作 方式一

  <form id="form1" enctype="multipart/form-data">
                <div style="float:right">
                    &nbsp;
                    <button type="button" class="btn btn-primary" onclick="$(‘#fileUpload‘).click()" id="reviewFile">浏览</button>
                    <button class="btn btn-primary" type="button" style="margin-left:5px;height:30px;" id="dataExport">批量导入</button>
                    <input type="button" class="btn btn-primary" style="margin-left:5px;height:30px;" id="downLoad" value="下载模板">
                </div>
                <div style="float:right;margin-top:5px">
                    <input id="fileUpload" name="fileUpload" type="file" style="display:none" />
                    <input id="fileText" type="text" class="form-control" disabled />
                </div>
                <script>
                    $("#fileUpload").change(function () {
                        $("#fileText").val($(this).val());
                    })
                </script>
            </form>

 //导入excel数据
        $("#dataExport").click(function () {
            var formData = new FormData($(‘form‘)[0]);
            $.ajax({
                url: ‘/BaseInfoPage/Upload‘,
                type: ‘POST‘,
                xhr: function () {
                    return $.ajaxSettings.xhr();
                },
                data: formData,
                cache: false,
                contentType: false,
                processData: false,
                success: function (data) {
                    if (data == "导入成功!") {
                        layer.msg(data, { icon: 1, time: 5000 }, function () {
                            location.reload();    //刷新父页面   第二个参数设置msg显示的时间长短
                        });
                    } else {
                        layer.msg(data, { icon: 0, time: 5000 }, function () {
                            return;
                        });
                    }

                },
                error: function (e) {
                    layer.msg(e, { icon: 0, time: 5000 }, function () {
                        return;
                    });
                }

            });
        })

 public string Upload(HttpPostedFileBase fileUpload)
        {
            if (fileUpload == null)
            {
                return "文件为空";
            }
            string fileExtension = Path.GetExtension(fileUpload.FileName);//获取文件名后缀
            try
            {
                //判断文件类型
                if (".xls" == fileExtension || ".xlsx" == fileExtension)
                {
                    //将硬盘路径转化为服务器路径的文件流
                    //string fileName = Path.Combine(Request.MapPath("~/ExcelTemplate"), Path.GetFileName(fileUpload.FileName));
                    string fileName = fileUpload.FileName;
                    string filePath = "";
                    filePath = CSysCfg.exFilePath;
                    if (!Directory.Exists(filePath))
                    {
                        Directory.CreateDirectory(filePath);
                    }
                    //保存模板到服务器            
                    fileUpload.SaveAs(filePath + "\\" + fileName);

                    //从NPOI读取到的Excel的数据，保存到excelTable里
                    DataTable excelTable = new DataTable();
                    excelTable = GetExcelDataTable(filePath + "\\" + fileName);//自定义方法

                    //把表的中文表头转换成数据库表中对应的英文
                    DataTable dbdata = new DataTable();
                    dbdata.Columns.Add("ltl_Id");
                    dbdata.Columns.Add("ltl_PlateId");
                    dbdata.Columns.Add("ltl_StarteTime");
                    dbdata.Columns.Add("ltl_EndTime");
                  
                    for (int i = 0; i < excelTable.Rows.Count; i++)
                    {
                        DataRow dr = excelTable.Rows[i];
                        DataRow dr_ = dbdata.NewRow();
                        dr_["ltl_Id"] = dr["申请编号"];
                        dr_["ltl_PlateId"] = dr["车牌号码"];
                        dr_["ltl_StarteTime"] = dr["开始日期"];
                        dr_["ltl_EndTime"] = dr["结束日期"];
                        dbdata.Rows.Add(dr_);
                    }
                    RemoveEmpty(dbdata);//自定义方法

                    //获取连接字符串，调用批量插入数据库的方法  需更改web.config添加配置
                    string constr = System.Configuration.ConfigurationManager.AppSettings["exportData"];
                    SqlBulkCopyByDatatable(constr, "LargeTransportLicense", dbdata);//自定义方法(连接字符串，表名，数据)
                    return "导入成功!";
                }
                else
                {
                    return "只可以选择Excel文件!";
                }
            }
            catch
            {
                return "导入失败!";
            }
        }
        // 从Excel中获取数据到DataTable   
        public static DataTable GetExcelDataTable(string filePath)
        {
            IWorkbook Workbook;
            DataTable table = new DataTable();
            try
            {
                using (FileStream fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
                {
                    //XSSFWorkbook 适用XLSX格式，HSSFWorkbook 适用XLS格式
                    string fileExt = Path.GetExtension(filePath).ToLower();
                    if (fileExt == ".xls")
                    {
                        Workbook = new HSSFWorkbook(fileStream);
                    }
                    else if (fileExt == ".xlsx")
                    {
                        Workbook = new XSSFWorkbook(fileStream);
                    }
                    else
                    {
                        Workbook = null;

                    }
                }
                //定位在第一个sheet
                ISheet sheet = Workbook.GetSheetAt(0);
                //第一行为标题行
                IRow headerRow = sheet.GetRow(1);
                int cellCount = headerRow.LastCellNum;// 是当前行的总列数
                int rowCount = sheet.LastRowNum;////LastRowNum 是当前表的总行数-1（注意）

                //循环添加标题列
                for (int i = headerRow.FirstCellNum; i < cellCount; i++)
                {
                    DataColumn column = new DataColumn(headerRow.GetCell(i).StringCellValue);
                    table.Columns.Add(column);
                }
                List<string> regionName = new List<string>();
                //数据
                for (int i = (sheet.FirstRowNum + 2); 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] = GetCellValue2(row.GetCell(j));

                            }
                            
                        }
                    }
                    table.Rows.Add(dataRow);
                }
            }
            catch (Exception ex)
            {
                throw ex;
            }
            return table;
        }

        //数据类型判断  方式一
        private static string GetCellValue(NPOI.SS.UserModel.ICell cell)
        {
            if (cell == null)
            {
                return string.Empty;
            }
            else
            {
                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://数值

                    case CellType.Unknown:
                    default:
                        return cell.ToString();
                    case CellType.String:
                        return cell.StringCellValue;
                    case CellType.Formula://公式
                        try
                        {
                            HSSFFormulaEvaluator e = new HSSFFormulaEvaluator(cell.Sheet.Workbook);
                            e.EvaluateInCell(cell);
                            return cell.ToString();
                        }
                        catch
                        {
                            return cell.NumericCellValue.ToString();
                        }
                }
            }
        }

        //数据类型判断，并设置为对应的数据类型 方式二
        public static object GetCellValue2(NPOI.SS.UserModel.ICell cell)
        {
            object value = null;
            if (cell == null)
            {
                value = 0;
            }
            try
            {
                if (cell.CellType != CellType.Blank)
                {
                    switch (cell.CellType)
                    {
                        case CellType.Blank:
                            value = string.Empty;
                            break;
                        case CellType.Numeric:
                            // 日期
                            if (DateUtil.IsCellDateFormatted(cell))
                            {
                                value = cell.DateCellValue;
                            }
                            else
                            {
                                // 数值
                                value = cell.NumericCellValue;
                            }
                            break;
                        case CellType.Boolean:
                            // Boolean type
                            value = cell.BooleanCellValue;
                            break;
                        case CellType.Formula:
                            value = cell.CellFormula;
                            break;
                        default:
                            // String type
                            value = cell.StringCellValue;
                            break;
                    }
                }
                else
                {
                    value = 0;
                }


            }
            catch (Exception)
            {
                value = 0;
            }

            return value;
        }

        /// <summary>
        /// 大数据插入
        /// </summary>
        /// <param name="connectionString">目标库连接</param>
        /// <param name="TableName">目标表</param>
        /// <param name="dtSelect">来源数据</param>
        public static void SqlBulkCopyByDatatable(string connectionString, string TableName, DataTable dtSelect)
        {
            using (SqlConnection conn = new SqlConnection(connectionString))
            {
                using (SqlBulkCopy sqlbulkcopy = new SqlBulkCopy(connectionString, SqlBulkCopyOptions.UseInternalTransaction))
                {
                    try
                    {
                        sqlbulkcopy.DestinationTableName = TableName;
                        sqlbulkcopy.BatchSize = 20000;
                        sqlbulkcopy.BulkCopyTimeout = 0;//不限时间
                        for (int i = 0; i < dtSelect.Columns.Count; i++)
                        {

                            sqlbulkcopy.ColumnMappings.Add(dtSelect.Columns[i].ColumnName, dtSelect.Columns[i].ColumnName);
                        }
                        sqlbulkcopy.WriteToServer(dtSelect);
                    }
                    catch (System.Exception ex)
                    {
                        throw ex;
                    }
                }
            }
        }

        //在导入Excel数据的时候，有时候会有空行，用RemoveEmpty方法去空
        protected void RemoveEmpty(DataTable dt)
        {
            List<DataRow> removelist = new List<DataRow>();
            for (int i = 0; i < dt.Rows.Count; i++)
            {
                bool IsNull = true;
                for (int j = 0; j < dt.Columns.Count; j++)
                {
                    if (!string.IsNullOrEmpty(dt.Rows[i][j].ToString().Trim()))
                    {
                        IsNull = false;
                    }
                }
                if (IsNull)
                {
                    removelist.Add(dt.Rows[i]);
                }
            }
            for (int i = 0; i < removelist.Count; i++)
            {
                dt.Rows.Remove(removelist[i]);
            }
        }