NPOI-导出excel文件

        /// <summary>
        /// DataTable转换成Excel文档流，并输出到客户端
        /// </summary>
        /// <param name="table"></param>
        /// <param name="response"></param>
        /// <param name="fileName">输出的文件名</param>
        public static void DataTableToExcel(DataTable table, HttpContext context, string fileName)
        {
            using (MemoryStream ms = DataTableToExcel(table))
            {
                RenderToBrowser(ms, context, fileName);
            }
        }


        /// <summary>
        /// DataTable转换成Excel文档流，并保存到文件
        /// </summary>
        /// <param name="table"></param>
        /// <param name="fileName">保存的路径</param>
        public static void DataTableToExcel(DataTable table, string fileName)
        {
            using (MemoryStream ms = DataTableToExcel(table))
            {
                SaveToFile(ms, fileName);
            }
        }


        /// <summary>
        /// DataTable转换成Excel文档流
        /// </summary>
        /// <param name="table"></param>
        /// <returns></returns>
        public static MemoryStream DataTableToExcel(DataTable dataTable)
        {
            MemoryStream ms = new MemoryStream();

            IWorkbook workbook = new HSSFWorkbook();
            ISheet sheet = workbook.CreateSheet("Sheet1");

            IRow headerRow = sheet.CreateRow(0);
            foreach (DataColumn column in dataTable.Columns)
            {
                headerRow.CreateCell(column.Ordinal).SetCellValue(column.ColumnName);
            }

            int rowIndex = 1;
            foreach (DataRow row in dataTable.Rows)
            {
                IRow excelRow = sheet.CreateRow(rowIndex);
                foreach (DataColumn column in dataTable.Columns)
                {
                    excelRow.CreateCell(column.Ordinal).SetCellValue(row[column].ToString());
                }
                rowIndex++;
            }

            workbook.Write(ms);

            return ms;
        }


        /// <summary>
        /// 保存Excel文档流到文件
        /// </summary>
        /// <param name="ms">Excel文档流</param>
        /// <param name="fileName">文件名</param>
        private static void SaveToFile(MemoryStream ms, string fileName)
        {
            using (FileStream fs = new FileStream(fileName, FileMode.Create, FileAccess.Write))
            {
                byte[] data = ms.ToArray();

                fs.Write(data, 0, data.Length);
                fs.Flush();

                data = null;
            }
        }


        /// <summary>
        /// 输出文件到浏览器
        /// </summary>
        /// <param name="ms">Excel文档流</param>
        /// <param name="context">HTTP上下文</param>
        /// <param name="fileName">文件名</param>
        private static void RenderToBrowser(MemoryStream ms, HttpContext context, string fileName)
        {
            if (context.Request.Browser.Browser == "IE")
            {
                fileName = HttpUtility.UrlEncode(fileName);
            }                
            // 设置响应的MIME类型
            context.Response.ContentType = "application/vnd.ms-excel";
            // 设置文件名并进行URL编码
            context.Response.AddHeader("Content-Disposition", "attachment;fileName=" + fileName);
            // 将内存流的内容写入响应输出流
            context.Response.BinaryWrite(ms.ToArray());
        }