Teach you step by step how to import mvc into excel_Practical tips

<p class="filebtn"> 
        @using (Html.BeginForm("importexcel", "foot", FormMethod.Post, new { enctype = "multipart/form-data" }))
          {
            <samp>请选择要上传的Excel文件：</samp>
            <span id="txt_Path"></span>
            <strong>选择文件<input name="file" type="file" id="file" /></strong>@*
            @Html.AntiForgeryToken() //防止跨站请求伪造(CSRF:Cross-site request forgery)攻击
           *@<input type="submit" id="ButtonUpload" value="提交"  class="offer"/> 
          }
      </p>

public class footController : Controller
  {
    //
    // GET: /foot/
    private static readonly String Folder = "/files";
    public ActionResult excel()
    {
      return View();
    }

    /// 导入excel文档
    public ActionResult importexcel()
    {
      //1.接收客户端传过来的数据
      HttpPostedFileBase file = Request.Files["file"];
      if (file == null || file.ContentLength <= 0)
      {
        return Json("请选择要上传的Excel文件", JsonRequestBehavior.AllowGet);
      }
      //string filepath = Server.MapPath(Folder);
      //if (!Directory.Exists(filepath))
      //{
      //  Directory.CreateDirectory(filepath);
      //}
      //var fileName = Path.Combine(filepath, Path.GetFileName(file.FileName));
      // file.SaveAs(fileName);
      //获取一个streamfile对象，该对象指向一个上传文件，准备读取改文件的内容
      Stream streamfile = file.InputStream;
      DataTable dt = new DataTable();
      string FinName = Path.GetExtension(file.FileName);
      if (FinName != ".xls" && FinName != ".xlsx")
      {
        return Json("只能上传Excel文档",JsonRequestBehavior.AllowGet);
      }
      else
      {
        try
        {
          if (FinName == ".xls")
          {
            //创建一个webbook，对应一个Excel文件(用于xls文件导入类)
            HSSFWorkbook hssfworkbook = new HSSFWorkbook(streamfile);
            dt = excelDAL.ImExport(dt, hssfworkbook);
          }
          else
          {
            XSSFWorkbook hssfworkbook = new XSSFWorkbook(streamfile);
            dt = excelDAL.ImExport(dt, hssfworkbook);
          }
          return Json("",JsonRequestBehavior.AllowGet);
        }
        catch(Exception ex)
        {
          return Json("导入失败 ！"+ex.Message, JsonRequestBehavior.AllowGet);
        }
    }
      
    }

}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using NPOI;
using NPOI.SS.UserModel;
using NPOI.HSSF.UserModel;
using System.Data;
using NPOI.XSSF.UserModel;

namespace GJL.Compoent
{
  public class excelDAL
  {
    ///<summary>
    /// #region 两种不同版本的操作excel
    /// 扩展名*.xlsx
    /// </summary>
    public static DataTable ImExport(DataTable dt, XSSFWorkbook hssfworkbook)
    {
      NPOI.SS.UserModel.ISheet sheet = hssfworkbook.GetSheetAt(0);
      System.Collections.IEnumerator rows = sheet.GetRowEnumerator();
      for (int j = 0; j < (sheet.GetRow(0).LastCellNum); j++)
      {
        dt.Columns.Add(sheet.GetRow(0).Cells[j].ToString());
      }
      while (rows.MoveNext())
      {
        XSSFRow row = (XSSFRow)rows.Current;
        DataRow dr = dt.NewRow();
        for (int i = 0; i < row.LastCellNum; i++)
        {
          NPOI.SS.UserModel.ICell cell = row.GetCell(i);
          if (cell == null)
          {
            dr[i] = null;
          }
          else
          {
            dr[i] = cell.ToString();
          }
        }
        dt.Rows.Add(dr);
      }
      dt.Rows.RemoveAt(0);
      if (dt!=null && dt.Rows.Count != 0)
      {
        for (int i = 0; i < dt.Rows.Count; i++)
        {
          string categary = dt.Rows[i]["页面"].ToString();
          string fcategary = dt.Rows[i]["分类"].ToString();
          string fTitle = dt.Rows[i]["标题"].ToString();
          string fUrl = dt.Rows[i]["链接"].ToString();
          FooterDAL.Addfoot(categary, fcategary, fTitle, fUrl);
        }
      }
      return dt;
    }

    #region 两种不同版本的操作excel
    ///<summary>
    /// 扩展名*.xls
    /// </summary>
    public static DataTable ImExport(DataTable dt, HSSFWorkbook hssfworkbook)
    {
      // 在webbook中添加一个sheet,对应Excel文件中的sheet,取出第一个工作表，索引是0 
      NPOI.SS.UserModel.ISheet sheet = hssfworkbook.GetSheetAt(0);
      System.Collections.IEnumerator rows = sheet.GetRowEnumerator();
      for (int j = 0; j < (sheet.GetRow(0).LastCellNum); j++)
      {
        dt.Columns.Add(sheet.GetRow(0).Cells[j].ToString());
      }
      while (rows.MoveNext())
      {
        HSSFRow row = (HSSFRow)rows.Current;
        DataRow dr = dt.NewRow();
        for (int i = 0; i < row.LastCellNum; i++)
        {
          NPOI.SS.UserModel.ICell cell = row.GetCell(i);
          if (cell == null)
          {
            dr[i] = null;
          }
          else 
          {
            dr[i] = cell.ToString();
          }
        }
        dt.Rows.Add(dr);
      }
      dt.Rows.RemoveAt(0);
      if (dt != null && dt.Rows.Count != 0)
      {
        for (int i = 0; i < dt.Rows.Count; i++)
        {
          string categary = dt.Rows[i]["页面"].ToString();
          string fcategary = dt.Rows[i]["分类"].ToString();
          string fTitle = dt.Rows[i]["标题"].ToString();
          string fUrl = dt.Rows[i]["链接"].ToString();
          FooterDAL.Addfoot(categary, fcategary, fTitle, fUrl);
        }

      }
      return dt;
    }
    #endregion
  }
}

 public static partial class FooterDAL
  {
    /// <summary>
    /// 添加
    /// </summary>
    /// <param name="id"></param>
    /// <param name="catgary"></param>
    /// <param name="fcatgary"></param>
    /// <param name="fTitle"></param>
    /// <param name="fUrl"></param>
    /// <returns></returns>
    public static int Addfoot(string categary, string fcategary, string fTitle, string fUrl)
    {
      string sql = string.Format("insert into Foot (categary,fcategary,fTitle,fUrl)values(@categary,@fcategary,@fTitle,@fUrl)");
      SqlParameter[] parm = 
        { 
           new SqlParameter("@categary",categary)
          ,new SqlParameter("@fcategary",fcategary)
          ,new SqlParameter("@fTitle",fTitle)
          ,new SqlParameter("@fUrl",fUrl)
        };
      return new DBHelperSQL<Foot>(CommonTool.dbname).ExcuteSql(sql,parm);  
    }
}