$firstLine = [
            'field1'=>'字段1',
            'field2'=>'字段2',
        ];
        $data = [
            [
                'field1' => 1,
                'field2' => 1,
            ]

        ];    
    csvDownLoad($data, $firstLine, '导出' . date('YmdHis', time()), $firstLine);
    /**
     * 描述 : csv导出
     * 作者 : Smart.Chen
     */
    function csvDownLoad($data = [], $firstLine = [], $title = '')
    {
        empty($title) && $title = '导出'.date('YmdHis');
        csv::download($title);
        csv::download(array_values($firstLine));
        foreach ($data as $v) {
            $arr = [];
            foreach ($firstLine as $filed => $filedName) {
                $arr[$filed] = isset($v[$filed]) ? $v[$filed] : '';
            }
            csv::download(array_values($arr));
        }
    }