public class Test
   public int Id { get; set; }
   public string Name { get; set; }
   public int Age { get; set; }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using OfficeOpenXml;
namespace WebApplication5.Controllers
[ApiController]
    public class ExecelController : ControllerBase
        [Route("api/Execel/TOExecel")]
        public IActionResult TOExecel()
            var list = new List<Test>();
            list.Add(new Test()
                Id = 1,
                Name = "Test",
                Age = 22,
            byte[] fileContents;
            using (ExcelPackage package = new ExcelPackage())
                ExcelWorksheet worksheet = package.Workbook.Worksheets.Add(".Net Core 导出");
                worksheet.Cells[1, 1].Value = "序号";
                worksheet.Cells[1, 2].Value = "Id";
                worksheet.Cells[1, 3].Value = "名称";
                worksheet.Cells[1, 4].Value = "年龄";
                int i = 2;
                foreach (var item in list)
                    worksheet.Cells["A" + i].Value = i - 1;
                   worksheet.Cells["B" + i].Value = item.Id;
                    worksheet.Cells["C" + i].Value = item.Name;
                    worksheet.Cells["D" + i].Value = item.Age;
                    i = i + 1;
                fileContents = package.GetAsByteArray();
                if (fileContents == null || fileContents.Length == 0)
                    return NotFound();
            return File(fileContents, "application/ms-excel", $"{Guid.NewGuid().ToString()}.xlsx");
}

[Route("api/Execel/Import")]
        public async Task<IActionResult> Import(IFormFile excelFile)
            var msg = "";
            if (excelFile == null || excelFile.Length <= 0)
                msg = "请选择导入文件!";
                return Ok(msg);
            if (!Path.GetExtension(excelFile.FileName).Equals(".xlsx", StringComparison.OrdinalIgnoreCase))
                msg = "请选择导入文件为.xlsx的后缀名!";
                return Ok(msg);
                using (var stream = new MemoryStream())
                    await excelFile.CopyToAsync(stream);
                     using (var package = new ExcelPackage(stream))
                        StringBuilder sb = new StringBuilder();
                        ExcelWorksheet worksheet = package.Workbook.Worksheets[0];
                        int rowCount = worksheet.Dimension.Rows;
                        int ColCount = worksheet.Dimension.Columns;
                        bool bHeaderRow = true;
                        for (int row = 2; row <= rowCount; row++)
                            Test model = new Test();
                            for (int col = 1; col <= ColCount; col++)
                                if (bHeaderRow)
                                    switch (col)
                                        case 1:
                                            model.Id = int.Parse(worksheet.Cells[row, col].Value.ToString());
                                            break;
                                        case 2:
                                            model.Name = worksheet.Cells[row, col].Value.ToString();
                                            break;
                                         case 3:
                                            model.Age = int.Parse(worksheet.Cells[row, col].Value.ToString());
                                            break;
                                    switch (col)
                                        case 1:
                                            model.Id = int.Parse(worksheet.Cells[row, col].Value.ToString());
                                            break;
                                        case 2:
                                            model.Name = worksheet.Cells[row, col].Value.ToString();
                                            break;
                                         case 3:
                                            model.Age = int.Parse(worksheet.Cells[row, col].Value.ToString());
                                           break;
                            //插入model即可
                msg = "导入成功!";
                return Ok(msg);