set_time_limit(0);
     ini_set('memory_limit', '1024M');
     $letter_all=[];
     $letter=['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'];
     
     
     // 标题字段  导出用户信息 field 要和数据库字段名称一致
     $title_arr=[
          ['title'=>'姓名','field'=>'name'],
          ['title'=>'性别','field'=>'sex'],
          ['title'=>'手机号码','field'=>'phone'],
      ];
      
      // 通过标题字段生成excel字母 例如3个字段，生成A-C
       $item=0;
        foreach($title_arr as $k => $v){
            if($item==26){
                $item=0;
            }
            $n=ceil(($k+1)/26);
            if($n==1){
                array_push($letter_all,$letter[$item]);
            }else{
                $n=$n-2;
                array_push($letter_all,$letter[$n].$letter[$item]);
            }
            $item++;
        }
        // 引入excel类
        // vendor('PHPExcel.PHPExcel');
        include_once(ROOT_PATH . 'extend/lib/PHPExcel.php');
        
        $fileName="学生数据".date('YmdHi'); // 导出标题
        $PHPExcel = new \PHPExcel();
        
        $PHPExcel->setActiveSheetIndex(0);
        $PHPExcel->getActiveSheet()->setTitle($fileName);
        
        
        # 生成Excel首行标题
        foreach($title_arr as $k=>$v){
           
            $PHPExcel->getActiveSheet()->setCellValue($letter_all[$k].'1', $v['title']);
            $PHPExcel->getActiveSheet()->getStyle($letter_all[$k].'1')->getFont()->setBold(true);//字体加粗
            // $PHPExcel->getActiveSheet()->getColumnDimension($letter_all[$k])->setAutoSize(true);//内容自适应
        }
        
        # 生成标题对应内容
        foreach($list as $k => $v){
            foreach($title_arr as $kk => $vv){
                $value=$v[$vv['field']];
                // 性别字段 存储数字1 2，1男 2女
                switch($vv['field']){
                    case 'sex':
                            if(!empty($value)){
                                $value=$value==1?'男':'女';
                            }
                        break;
                }
                $PHPExcel->getActiveSheet()->setCellValue($letter_all[$kk].($k+2), $value);
               
            }
           
        }
        
        //保存为2003格式
        // $objWriter = new \PHPExcel_Writer_Excel5($PHPExcel);

        //生成2007格式
        $objWriter = \PHPExcel_IOFactory::createWriter($PHPExcel, 'Excel2007');
        
        header("Pragma: public");
        header("Expires: 0");
        header("Cache-Control:must-revalidate, post-check=0, pre-check=0");
        header("Content-Type:application/force-download");
        header("Content-Type:application/vnd.ms-execl");
        header("Content-Type:application/octet-stream");
        header("Content-Type:application/download");

                //多浏览器下兼容中文标题
                $encoded_filename = urlencode($fileName);
                $ua = $_SERVER["HTTP_USER_AGENT"];
                if (preg_match("/MSIE/", $ua)) {
                    header('Content-Disposition: attachment; filename="' . $encoded_filename . '.xlsx"');
                } else if (preg_match("/Firefox/", $ua)) {
                    header('Content-Disposition: attachment; filename*="utf8\'\'' . $fileName . '.xlsx"');
                } else {
                    header('Content-Disposition: attachment; filename="' . $fileName . '.xlsx"');
                }
               
                header("Content-Transfer-Encoding:binary");
                $objWriter->save('php://output');