使用NPOI，完成数据的导入导出

解释下流程，第一步：将数据库表中的数据导出到excel表
                          第二步：将excel表中的数据再插入到数据库表中（当然没有做重复性校验，测试而已）
注：表结构很简单：
　　Id (int) 自增
　　Name (nvarchar(20))
　　Age (int)
　　Phone(nvarchar(13))

  class Program
     {
         /* 首先用ado.net简单封装下 Insert和Select操作，导入导出要用到*/

         //封装ado.net  Insert操作
         static void Insert(string sql, params SqlParameter[] parameters)
         {
             string connstr = ConfigurationManager.ConnectionStrings["connstr"].ConnectionString;
             using (SqlConnection conn = new SqlConnection(connstr))
             {
                 conn.Open();
                 using (SqlCommand cmd = conn.CreateCommand())
                 {
                     cmd.CommandText = sql;
                     cmd.Parameters.AddRange(parameters);
                     cmd.ExecuteNonQuery();
                 }
             }
         }

         //封装ado.net Select操作
         static DataTable Select(string sql, params SqlParameter[] parameters)
         {
             DataTable table = new DataTable();
             string connstr = ConfigurationManager.ConnectionStrings["connstr"].ConnectionString;
             using (SqlConnection conn = new SqlConnection(connstr))
             {
                 conn.Open();
                 using (SqlCommand cmd = conn.CreateCommand())
                 {
                     cmd.CommandText = sql;
                     cmd.Parameters.AddRange(parameters);
                     using (SqlDataReader read = cmd.ExecuteReader())
                     {
                         table.Load(read);
                     }
                 }
             }
             return table;
         }

         /*封装导入导出方法*/

         //从数据库表中导出数据到excel表中
         static void Export_toxlsx()
         {
             IWorkbook wb = new XSSFWorkbook();
             ISheet sheet =  wb.CreateSheet("sheet1");  //创建工作簿“sheet1”
            /*表头*/
            IRow title =  sheet.CreateRow();
             ICell cell_0 = title.CreateCell();
             cell_0.SetCellValue("姓名");
             ICell cell_1 = title.CreateCell();
             cell_1.SetCellValue("年龄");
             ICell cell_2 = title.CreateCell();
             cell_2.SetCellValue("电话");
             /*表内容*/
             DataTable tb = Select("select * from t_test");
             int i = ;
             foreach(DataRow item in tb.Rows)
             {
                 IRow row = sheet.CreateRow(i);
                 ICell cell0 = row.CreateCell();
                 cell0.SetCellValue((string)item["Name"]);
                 ICell cell1 = row.CreateCell();
                 cell1.SetCellValue((int)item["Age"]);
                 ICell cell2 = row.CreateCell();
                 cell2.SetCellValue((string)item["Phone"]);
                 i++;
             }

             using (Stream stream = File.OpenWrite(@"e:/test/test.xlsx"))
             {
                 wb.Write(stream); //将使用npoi创建的xlsx文件写入到流中
             }
             Console.WriteLine("Export Done!");
         }
         //从excel表中将数据导入到数据库中
         static void Import_toDb()
         {
             IWorkbook wb = WorkbookFactory.Create(@"e:/test/test.xlsx");
             ISheet sheet = wb.GetSheetAt(); //获取test.xlsx的第一个工作簿

             for(int i=; i<=sheet.LastRowNum;i++) //从第一行开始读，第0行为表头
             {
                 IRow row = sheet.GetRow(i);
                 ICell cell_0 = row.GetCell();
                 ICell cell_1 = row.GetCell();
                 ICell cell_2 = row.GetCell();

                 Insert("insert into t_test (Name,Age,Phone) values(@Name,@Age,@Phone)",
                     new SqlParameter("@Name",cell_0.StringCellValue),
                     new SqlParameter("@Age",(int)cell_1.NumericCellValue),
                     new SqlParameter("@Phone",cell_2.StringCellValue));
             }
             Console.WriteLine("Inset Done!");
         }
         static void Main(string[] args)
         {

             Export_toxlsx();
             Import_toDb();
             Console.ReadKey();
         }

     }