Thinkphp5控制器实现树状分类

Public function getrtree(){
       
        $data[]=array('id'=>1,'pid'=>0,'name'=>'中国');
        $data[]=array('id'=>2,'pid'=>0,'name'=>'美国');
        $data[]=array('id'=>3,'pid'=>0,'name'=>'韩国');
        $data[]=array('id'=>4,'pid'=>1,'name'=>'北京');
        $data[]=array('id'=>5,'pid'=>1,'name'=>'上海');
        $data[]=array('id'=>6,'pid'=>1,'name'=>'广西');
        $data[]=array('id'=>7,'pid'=>6,'name'=>'桂林');
        $data[]=array('id'=>8,'pid'=>6,'name'=>'南宁');
        $data[]=array('id'=>9,'pid'=>6,'name'=>'柳州');
        $data[]=array('id'=>10,'pid'=>2,'name'=>'纽约');
        $data[]=array('id'=>11,'pid'=>2,'name'=>'华盛顿');
        $data[]=array('id'=>12,'pid'=>3,'name'=>'首尔');
       
        $tree=$this->build_tree($data,0);
        print_r($tree);
        print(json_encode($tree,true));
       
    }


    function findChild(&$arr,$id){
        $childs=array();
        foreach ($arr as $k => $v){
            if($v['pid']== $id){
                $childs[]=$v;
            }
        }
        return $childs;
    }
   
    function build_tree($rows,$root_id){
        $childs=$this->findChild($rows,$root_id);
        if(empty($childs)){
            return null;
        }
        foreach ($childs as $k => $v){
            $rescurTree=$this->build_tree($rows,$v['id']);
            if( null != $rescurTree){
                $childs[$k]['childs']=$rescurTree;
            }
        }
        return $childs;
    }