【NPOI】WebAPI-使用NPOI导出Excel

1.安装nuget包

2.封装方法

　　　　 public byte[] ExportToByteArray(IEnumerable<string> headerText,
                                        IEnumerable<string[]> dataList,
                                        string extraMessage = null)
        {
            IWorkbook workbook = Write(headerText, dataList, extraMessage);
            var memoryStream = new MemoryStream();
            workbook.Write(memoryStream);

            return memoryStream.ToArray();
        }
        
        private static IWorkbook Write(IEnumerable<string> headerText,
                                       IEnumerable<string[]> dataList,
                                       string extraMessage = null)
        {
            IWorkbook wb = new XSSFWorkbook();
            ISheet sheet = wb.CreateSheet("Sheet1");
            var rowIndex = 0;

            if (!string.IsNullOrEmpty(extraMessage))
            {
                SetExcelRowForExtraMessage(sheet, extraMessage);
                rowIndex += 1;
            }

            SetExcelHeaderRow(sheet, rowIndex, headerText.ToList());
            rowIndex += 1;

            if (!dataList.Any())
            {
                return wb;
            }

            for (var i = 0; i < dataList.Count(); i++)
            {
                SetExcelBodyRow(sheet, rowIndex + i, dataList.ElementAt(i));
            }

            //优化表格的列宽
            int maxColumnIndex = dataList.Max(row => row.Count());
            for (var i = 0; i < maxColumnIndex; i++)
            {
                sheet.AutoSizeColumn(i);
            }

            return wb;
        }

3.Controller调用方法

  　　　 /// <summary>
        /// 基金净值下载
        /// </summary>
        [HttpGet]
        public HttpResponseMessage DownloadExecl()
        {
            try
            {
                //获取数据         var productList = _productService.GetProductList();

                var exportData = ProductList.Select(t => new {
                    t.Date,
                    t.Name
                }).ToList();
                //下载文件
                var fileName = $"{DateTime.Today:yyyyMMdd}.xlsx";
                var bytes = _exportor.ExportToByteArray(HeaderText, exportData, "");
                var response = GetFileResponse(fileName, bytes);

                return response;
            }
            catch (Exception)
            {
               return new HttpResponseMessage(System.Net.HttpStatusCode.NoContent);
            }
        }

        private HttpResponseMessage GetFileResponse(string fileName, byte[] bytes)
        {
            HttpResponseMessage response = new HttpResponseMessage(System.Net.HttpStatusCode.OK);
            var mime = System.Web.MimeMapping.GetMimeMapping(fileName);
            var stream = new MemoryStream(bytes);
            response.Content = new StreamContent(stream);
            response.Content = new StreamContent(stream);
            bool isFirefox = Request.Headers.UserAgent.ToString()
                                .IndexOf("Firefox", StringComparison.CurrentCultureIgnoreCase) > -1;
            response.Content.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue(mime);
            response.Content.Headers.ContentDisposition =
                    new ContentDispositionHeaderValue("attachment")
                    {
                            FileName = isFirefox ? fileName :
                            HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8)
                    };
            response.Content.Headers.ContentLength = stream.Length;

            return response;
        }

　　　　 /// <summary>
        /// Excel列头
        /// </summary>
        private static readonly string[] HeaderText =
        {
            "时间",
            "名称"
        };

ASP.NET MVC

ACTION

        /// <summary>
        /// Action
        /// </summary>
        public FileResult ExportExcel(string name)
        {
            var results = new List<Student>
            {
                new Student {Name = "james",Address = "Los Angeles"},
                new Student {Name = "londo",Address = "Cleveland"}
            };

            var dt = new DataTable();
            dt.Columns.Add("姓名");
            dt.Columns.Add("地址");

            foreach (var item in results)
            {
                DataRow dr = dt.NewRow();
                dr["姓名"] = item.Name;
                dr["地址"] = item.Address;
                dt.Rows.Add(dr);
            }
            var stream = ExcelUtil.TableToExcel(dt);
            return File(stream, "application/x-xls", "学生信息.xls");
        }

common

using System.Data;
using System.IO;
using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;

namespace Common
{
    /// <summary>
    /// Excel 数据导出、导入
    /// </summary>
    public static class ExcelUtil
    {
        /// <summary>
        /// Datable导出成Excel
        /// </summary>
        /// <param name="dt"></param>
        /// <param name="file">导出路径(包括文件名与扩展名)</param>
        public static byte[] TableToExcel(DataTable dt)
        {
            IWorkbook workbook;
            workbook = new HSSFWorkbook();
            //if (fileExt == ".xlsx") { workbook = new XSSFWorkbook(); } else if (fileExt == ".xls") { ; } else { workbook = null; }
            //if (workbook == null) { return null; }
            ISheet sheet = string.IsNullOrEmpty(dt.TableName) ? workbook.CreateSheet("Sheet1") : workbook.CreateSheet(dt.TableName);

            //表头  
            IRow row = sheet.CreateRow(0);
            for (int i = 0; i < dt.Columns.Count; i++)
            {
                ICell cell = row.CreateCell(i);
                cell.SetCellValue(dt.Columns[i].ColumnName);
            }

            //数据  
            for (int i = 0; i < dt.Rows.Count; i++)
            {
                IRow row1 = sheet.CreateRow(i + 1);
                for (int j = 0; j < dt.Columns.Count; j++)
                {
                    ICell cell = row1.CreateCell(j);
                    cell.SetCellValue(dt.Rows[i][j].ToString());
                }
            }

            //转为字节数组  
            MemoryStream stream = new MemoryStream();
            workbook.Write(stream);
            var buf = stream.ToArray();
            return buf;
        }

    }
}

前端调用：

无参

// 导出
$(".export_btn").click(function () {
    window.open("/controller/action");
})

有参：

$('#export_btn').click(function () {
     var url ="/controller/action";
     url += "?a=" + $('#a').val();
     url += "&b=" + $('#b').val();
     window.open(url);
});

导入

        /// <summary>
        /// 导入
        /// </summary>
        public JsonResult ImportPdm(HttpPostedFileBase file)
        {
            var fileName = file?.FileName;

            var msg = string.IsNullOrWhiteSpace(fileName) ? "上传文件为空" : $"{fileName} 上传成功";

            List<Pdm> data = ReadFromExcel(file, GetPdm);

            return Json(new { Msg = msg });
        }

        private List<Pdm> ReadFromExcel(HttpPostedFileBase httpPostedFileBase, Func<IRow, int, Pdm> convertToPdm)
        {
            var list = new List<Pdm>();
            IWorkbook wk = null;

            string extension = System.IO.Path.GetExtension(httpPostedFileBase.FileName)?.ToLower();
            if (extension != null && extension.Equals(".xls"))
            {
                wk = new HSSFWorkbook(httpPostedFileBase.InputStream);
            }
            else
            {
                wk = new XSSFWorkbook(httpPostedFileBase.InputStream);
            }

            ISheet sheet = wk.GetSheetAt(0); // 第0个sheet
            int offset = 1;
            for (int i = offset; i <= sheet.LastRowNum; i++)
            {
                var model = convertToPdm(sheet.GetRow(i), i + 1);
                if (model == null) break;
                 
                list.Add(model);
            }
            return list;
        }

        private Pdm GetPdm(IRow row, int index)
        {
            var model = new Pdm();
            SetCellType(row, CellType.String);
            model.TechnologyName = row.GetCell(0).StringCellValue.Trim();
            model.Number = row.GetCell(1).StringCellValue.Trim();
            model.Workshop = row.GetCell(2).StringCellValue.Trim(); 
          
            return model;
        }

        private void SetCellType(IRow row, CellType type)
        {
            row.GetCell(0).SetCellType(type);
            row.GetCell(1).SetCellType(type);
            row.GetCell(2).SetCellType(type);
        }