系统中经常用需要读取Excel文件中的数据，导入到数据库，下面是一个示例。

vs：2022

框架：abpvnext 3.1

把Excel中的数据导入到数据库

/// <summary>
/// 导入
/// </summary>
/// <param name="formFile"></param>
/// <returns></returns>
[HttpPost("DefectiveReasonImport")]
public async Task<IActionResult> DefectiveReasonImportAsync(IFormFile formFile)
{string resultMsg = string.Empty;var result = false;int j = 0;//记录行数try{if (formFile.Length > 0){var stopWatch = new Stopwatch();stopWatch.Start();#region 防呆验证//将excel表格中的数据转化为dataTable数据var getDataTable = NpoiExcelHelper.helper.ExcelToDataTable(formFile.OpenReadStream(), Path.GetExtension(formFile.FileName), out result, out resultMsg);if (getDataTable.Rows.Count <= 0) throw new Exception($"Excel表中无数据可导入");var columnData = getDataTable.AsEnumerable().Select(row => row.Field<string>("编码")).ToList();for (int i = 0; i < getDataTable.Rows.Count; i++){if (getDataTable.Rows[i][0].ToString() == "") throw new Exception($"第[{i + 2}]行，编码不可为空");if (getDataTable.Rows[i][1].ToString() == "") throw new Exception($"第[{i + 2}]行，不良原因不可为空");var query = _defectiveReasonRepository.Where(d => d.Code == getDataTable.Rows[i][0].ToString());if (query.Any())throw new Exception($"第[{i + 2}]行，表中已存在编码[{getDataTable.Rows[i][0].ToString()}]");}//var codeColumnNullOrEmpty = columnData.Where(d => string.IsNullOrEmpty(d));//if (codeColumnNullOrEmpty.Any()) throw new Exception($"编码不可为空");var codeColumnGroupList = columnData.GroupBy(d => d).Where(d => d.Count() > 1).Select(d => d.Key).ToList();if (codeColumnGroupList != null && codeColumnGroupList.Count > 0) throw new Exception($"编码存在重复[{codeColumnGroupList.JoinAsString(",")}]");//var nameColumnNullOrEmpty = columnData.Where(d => string.IsNullOrEmpty(d));//if (nameColumnNullOrEmpty.Any()) throw new Exception($"不良原因不可为空");#endregion#region 向数据库新增数据for (int i = 0; i < getDataTable.Rows.Count; i++){j = i;var defectiveReasonCreateDto = new DefectiveReasonCreateUpdateDto{Code = getDataTable.Rows[i][0].ToString(),Name = getDataTable.Rows[i][1].ToString(),Status = (getDataTable.Rows[i][2] != null && !string.IsNullOrEmpty(getDataTable.Rows[i][2].ToString())) ? Convert.ToBoolean(getDataTable.Rows[i][2]) : true};var defectiveReason = ObjectMapper.Map<DefectiveReasonCreateUpdateDto, DefectiveReason>(defectiveReasonCreateDto);defectiveReason.ChangeCreateUser(DateTime.Now, CurrentUser.Id.ToString());await _defectiveReasonRepository.InsertAsync(defectiveReason);}#endregionstopWatch.Stop();resultMsg = $"Excel导入成功,耗费总时长{stopWatch.Elapsed.TotalSeconds}秒，总共导入{getDataTable.Rows.Count}条数据";}else{resultMsg = "Excel表中无数据可导入！";}}catch (Exception e){await CurrentUnitOfWork.RollbackAsync();result = false;resultMsg = $"{e.Message}";}return Ok(new { status = result ? 0 : 1, message = resultMsg });
}

Excel帮助类

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 Imagine.Mes.MesBase.Application.CommonTool
{/// <summary>/// Excel帮助类/// </summary>public class NpoiExcelHelper{private static NpoiExcelHelper _excelImportHelper;public static NpoiExcelHelper helper{get => _excelImportHelper ?? (_excelImportHelper = new NpoiExcelHelper());set => _excelImportHelper = value;}/// <summary>/// 读取excel表格中的数据,将Excel文件流转化为dataTable数据源  /// 默认第一行为标题 /// </summary>/// <param name="stream">excel文档文件流</param>/// <param name="fileType">文档格式</param>/// <param name="isSuccess">是否转化成功</param>/// <param name="resultMsg">转换结果消息</param>/// <returns></returns>public DataTable ExcelToDataTable(Stream stream, string fileType, out bool isSuccess, out string resultMsg){isSuccess = false;resultMsg = "Excel文件流成功转化为DataTable数据源";var excelToDataTable = new DataTable();try{//Workbook对象代表一个工作簿,首先定义一个Excel工作薄IWorkbook workbook;//XSSFWorkbook 适用XLSX格式，HSSFWorkbook 适用XLS格式#region 判断Excel版本switch (fileType){//.XLSX是07版(或者07以上的)的Office Excelcase ".xlsx":workbook = new XSSFWorkbook(stream);break;//.XLS是03版的Office Excelcase ".xls":workbook = new HSSFWorkbook(stream);break;default:throw new Exception("Excel文档格式有误");}#endregionvar sheet = workbook.GetSheetAt(0);var rows = sheet.GetRowEnumerator();var headerRow = sheet.GetRow(0);int cellCount = headerRow.LastCellNum;//最后一行列数（即为总列数）//获取第一行标题列数据源,转换为dataTable数据源的表格标题名称for (var j = 0; j < cellCount; j++){var cell = headerRow.GetCell(j);excelToDataTable.Columns.Add(cell.ToString());}//获取Excel表格中除标题以为的所有数据源，转化为dataTable中的表格数据源for (var i = (sheet.FirstRowNum + 1); i <= sheet.LastRowNum; i++){var dataRow = excelToDataTable.NewRow();var row = sheet.GetRow(i);if (row == null) continue; //没有数据的行默认是null　for (int j = row.FirstCellNum; j < cellCount; j++){if (row.GetCell(j) != null)//单元格内容非空验证{#region NPOI获取Excel单元格中不同类型的数据//获取指定的单元格信息var cell = row.GetCell(j);switch (cell.CellType){//首先在NPOI中数字和日期都属于Numeric类型//通过NPOI中自带的DateUtil.IsCellDateFormatted判断是否为时间日期类型case CellType.Numeric when DateUtil.IsCellDateFormatted(cell):dataRow[j] = cell.DateCellValue;break;case CellType.Numeric://其他数字类型dataRow[j] = cell.NumericCellValue;break;//空数据类型case CellType.Blank:dataRow[j] = "";break;//公式类型case CellType.Formula:{HSSFFormulaEvaluator eva = new HSSFFormulaEvaluator(workbook);dataRow[j] = eva.Evaluate(cell).StringValue;break;}//布尔类型case CellType.Boolean:dataRow[j] = row.GetCell(j).BooleanCellValue;break;错误//case CellType.Error://    dataRow[j] = HSSFErrorConstants.GetText(row.GetCell(j).ErrorCellValue);//    break;//    //其他类型都按字符串类型来处理（未知类型CellType.Unknown，字符串类型CellType.String）default:dataRow[j] = cell.StringCellValue;break;}#endregion}}excelToDataTable.Rows.Add(dataRow);}isSuccess = true;}catch (Exception e){resultMsg = e.Message;}return excelToDataTable;}}
}