laravel无限级分类

数据库:

遍历函数:

public function tree($parentId = 0)    {        $rows = Category::where('parentId', $parentId)->get()->toArray();        $arr = array();        if (sizeof($rows) != 0){            foreach ($rows as $key => $val){                $val['list'] = $this->tree($val['id']);                $arr[] = $val;            }            return $arr;        }    }