PHP导出CSV

$header = array(
            'id' => 'ID',
            'create_time' => '提交时间'
        );
header('Content-Type: application/vnd.ms-excel');
        header('Content-Disposition: attachment;filename="明细.csv"');
        header('Cache-Control: max-age=0');
        $fp = fopen('php://output', 'a');
        //导出表头
        $header_arr = array();
        foreach( $header as $key => $val ) {
            $header_arr[] = mb_convert_encoding($val,'gbk','utf8');
        }
        fputcsv($fp, $header_arr);

        $start = 0;
        $offset = 5000;
        if( $count['num'] > 0 ) {
            while( true ) {
                ob_flush();
                flush();
                $args['start'] = $start;
                $args['offset'] = $offset;
                $info = $this->get_list($args);
                if( !empty($info) ) {
                    foreach( $info as $row ) {
                        $one_row = array();
                        foreach( $header as $key => $val ) {
                            $one_row[]=mb_convert_encoding((string)$row[$key],'gbk','utf8');
                        }
                        fputcsv($fp, $one_row);
                    }
                } else {
                    break;
                }
                $start +=5000;
            }
        }