代码：

/**
     * 列表
     */
    public function listQueryAndChildren(){
			$rs = cache('GOODS_CAT');
			if(!$rs){
					$data = $this->where("dataFlag=1")->field('catId,catTitle,parentId')->select();
					$rs = $this->getTree($data, 0,1);
					cache('GOODS_CAT',$rs,86400);
			}
			return $rs;
	}
	/**
	 * 组装二级分类
	 * $deep 分类深度
	 */
	public function getTree($data,$parentId,$deep){
			$tree = [];
			$deep++;
			foreach($data as $k=>$v){
					if($v['parentId']==$parentId){
							// 再找其下级分类
							if($deep <= 2){
									$v['children'] = $this->getTree($data,$v['catId'],$deep);
							}               
							$tree[] = $v;
					}
			}
			return $tree;
	}