.Net core 使用NPOI 直接导入Excel到数据库（即不先将Excel保存到服务器再读取文件到数据库）

         /// <summary>
         /// 导入信息
         /// </summary>
         /// <param name="file"></param>
         /// <returns></returns>
         /// /Public/PublicPool/ImportCustomer
         public ResultData ImportCustomer(IFormFile file)
         {
             ResultData resultData = new ResultData();
             if (file.Length > )
             {
                 DataTable dt = new DataTable();
                 string strMsg;
     //利用IFormFile里面的OpenReadStream()方法直接读取文件流
                 dt = ExcelHelper.ExcelToDatatable(file.OpenReadStream(), Path.GetExtension(file.FileName), out strMsg);
                 if (!string.IsNullOrEmpty(strMsg))
                 {
                     resultData.Code = -;
                     resultData.Msg = strMsg;
                     return resultData;
                 }
                 if (dt.Rows.Count > )
                 {
                 }
                 else
                 {
                     resultData.Code = -;
                     resultData.Msg = "Excel导入表无数据!";
                 }
             return resultData;
         }

 using NPOI.HSSF.UserModel;
 using NPOI.SS.UserModel;
 using NPOI.XSSF.UserModel;
 using System;
 using System.Collections.Generic;
 using System.Data;
 using System.IO;
 using System.Text;

 namespace CRM.Common
 {
     public static class ExcelHelper
     {
         /// <summary>
         /// 将Excel单表转为Datatable
         /// </summary>
         /// <param name="stream"></param>
         /// <param name="fileType"></param>
         /// <param name="strMsg"></param>
         /// <param name="sheetName"></param>
         /// <returns></returns>
         public static DataTable ExcelToDatatable(Stream stream, string fileType, out string strMsg, string sheetName = null)
         {
             strMsg = "";
             DataTable dt = new DataTable();
             ISheet sheet = null;
             IWorkbook workbook = null;
             try
             {
                 #region 判断excel版本
                 //2007以上版本excel
                 if (fileType == ".xlsx")
                 {
                     workbook = new XSSFWorkbook(stream);
                 }
                 //2007以下版本excel
                 else if (fileType == ".xls")
                 {
                     workbook = new HSSFWorkbook(stream);
                 }
                 else
                 {
                     throw new Exception("传入的不是Excel文件！");
                 }
                 #endregion
                 if (!string.IsNullOrEmpty(sheetName))
                 {
                     sheet = workbook.GetSheet(sheetName);
                     if (sheet == null)
                     {
                         sheet = workbook.GetSheetAt();
                     }
                 }
                 else
                 {
                     sheet = workbook.GetSheetAt();
                 }
                 if (sheet != null)
                 {
                     IRow firstRow = sheet.GetRow();
                     int cellCount = firstRow.LastCellNum;
                     for (int i = firstRow.FirstCellNum; i < cellCount; i++)
                     {
                         ICell cell = firstRow.GetCell(i);
                         if (cell != null)
                         {
                            string cellValue = cell.StringCellValue.Trim();
                             if (!string.IsNullOrEmpty(cellValue))
                             {
                                 DataColumn dataColumn = new DataColumn(cellValue);
                                 dt.Columns.Add(dataColumn);
                             }
                         }
                     }
                     DataRow dataRow = null;
                     //遍历行
                     for (int j = sheet.FirstRowNum + ; j <= sheet.LastRowNum; j++)
                     {
                         IRow row = sheet.GetRow(j);
                         dataRow = dt.NewRow();
                         if (row == null || row.FirstCellNum < )
                         {
                             continue;
                         }
                         //遍历列
                         for (int i = row.FirstCellNum; i < cellCount; i++)
                         {
                             ICell cellData = row.GetCell(i);
                             if (cellData != null)
                             {
                                 //判断是否为数字型，必须加这个判断不然下面的日期判断会异常
                                 if (cellData.CellType == CellType.Numeric)
                                 {
                                     //判断是否日期类型
                                     if (DateUtil.IsCellDateFormatted(cellData))
                                     {
                                         dataRow[i] = cellData.DateCellValue;
                                     }
                                     else
                                     {
                                         dataRow[i] = cellData.ToString().Trim();
                                     }
                                 }
                                 else
                                 {
                                     dataRow[i] = cellData.ToString().Trim();
                                 }
                             }
                         }
                         dt.Rows.Add(dataRow);
                     }
                 }
                 else
                 {
                     throw new Exception("没有获取到Excel中的数据表！");
                 }
             }
             catch (Exception ex)
             {
                 strMsg = ex.Message;
             }
             return dt;
         }
     }
 }

网上找了好多都没有直接保存导数据库的方法，自己研究了IFormFile类后尝试了一下没想到意外的成功了~~~~~~~~~~