require_once dirname(__FILE__).'/Classes/PHPExcel.php';//引入PHPExcel
.....此处略去从数据库获取数据的过程，$a为需要导出的数组......
$numArr = array('A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z','AA','AB','AC','AD','AE','AF','AG','AH','AI','AJ','AK','AL','AM','AN','AO','AP','AQ','AR','AS','AT','AU','AV','AW','AX','AY','AZ');
// Create new PHPExcel object
$objPHPExcel = new PHPExcel();

$arr = array('订单号','下单时间','城市','地区', '客户名称', '收货人', '联系电话', '收货地址', 'ERP客户名称', '物流系统客户名称', '活动项目',
 '品牌', '型号', '颜色', '物流系统型号', '订货量', '单价', '代收货款', '红包', '价保返利', '运费', '实收金额', '付款方式', '订单来源',
 '上游厂商', '是否在仓', '快递面单号', '订单状态', '确认时间', '末次状态确认时间', '描述', '对应业务', '对应客服', '商家留言', '下单摘要',
 '业务员', '联系方式');
// 输出标题
echo date('H:i:s') , " Add some data" , EOL;
//设置换行
$objPHPExcel->getActiveSheet()->getStyle('H')->getAlignment()->setWrapText(true);
$objPHPExcel->getActiveSheet()->getStyle('Y')->getAlignment()->setWrapText(true);
//设置相应列的宽度
$objPHPExcel->setActiveSheetIndex(0)->getColumnDimension('A')->setWidth(15);
$objPHPExcel->setActiveSheetIndex(0)->getColumnDimension('B')->setWidth(20);
$objPHPExcel->setActiveSheetIndex(0)->getColumnDimension('G')->setWidth(15);
$objPHPExcel->setActiveSheetIndex(0)->getColumnDimension('H')->setWidth(40);
$objPHPExcel->setActiveSheetIndex(0)->getColumnDimension('I')->setWidth(15);
$objPHPExcel->setActiveSheetIndex(0)->getColumnDimension('J')->setWidth(15);
//输出第一行
$objPHPExcel->setActiveSheetIndex(0)
   ->setCellValue('A1', $arr[0])
 ->setCellValue('B1', $arr[1])
 ->setCellValue('C1', $arr[2])
 ->setCellValue('D1', $arr[3])
 ->setCellValue('E1', $arr[4])
 ->setCellValue('F1', $arr[5])
 ->setCellValue('G1', $arr[6])
 ->setCellValue('H1', $arr[7])
 ->setCellValue('I1', $arr[8])
 ->setCellValue('J1', $arr[9])
   ->setCellValue('K1', $arr[10])
   ->setCellValue('L1', $arr[11]);


//输出内容
for($i=0;$i<count($a);$i++){
 $objPHPExcel->setActiveSheetIndex(0)
  ->setCellValue($numArr[0].($i+2), $a[$i]['order_sn'])
  ->setCellValue($numArr[1].($i+2), $a[$i]['add_time'])
  ->setCellValue($numArr[2].($i+2), $a[$i]['city'])
  ->setCellValue($numArr[3].($i+2), $a[$i]['region_name'])
  ->setCellValue($numArr[4].($i+2), $a[$i]['company'])
  ->setCellValue($numArr[5].($i+2), $a[$i]['consignee'])
  ->setCellValue($numArr[6].($i+2), $a[$i]['mobile'])
  ->setCellValue($numArr[7].($i+2), $a[$i]['address'])
  ->setCellValue($numArr[8].($i+2), '')
  ->setCellValue($numArr[9].($i+2), '')
  ->setCellValue($numArr[10].($i+2), '')
  ->setCellValue($numArr[11].($i+2), $a[$i]['brand_name']);
}

// Rename worksheet
echo date('H:i:s') , " Rename worksheet" , EOL;
$dirName = date("Ymd");//目录名
$fileName = date("YmdHis");//文件名
$objPHPExcel->getActiveSheet()->setTitle($fileName);


// Set active sheet index to the first sheet, so Excel opens this as the first sheet
$objPHPExcel->setActiveSheetIndex(0);


// Save Excel 2007 file
echo date('H:i:s') , " Write to Excel2007 format" , EOL;
$callStartTime = microtime(true);
if(!opendir('../excel/'.$dirName)){
 mkdir('../excel/'.$dirName);
}
$objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'Excel2007');
$objWriter->save('../excel/'.$dirName.'/'.$fileName.'.xlsx');

$end = getCurrentTime();
$spend = $end-$begin;
if ($spend > 30){
 echo '<script>if(confirm("执行超时！")){ window.history.back(-1);}</script>';
 exit;
}
header('Location:http://'.$_SERVER['HTTP_HOST'].'/excel/'.$dirName.'/'.$fileName.'.xlsx');