无限分类树操作

public static function getCategoryTree($id){
        //$model=M(‘category‘);
        if($id>0){            
            $obj=self::selectTable(‘category‘,array(‘id‘=>$id),true);//$model->where(array(‘id‘=>$id))->find();
            if(!is_null($obj)){
                $childList=self::selectTable(‘category‘,array(‘parent_id‘=>$id));//$model->where(array(‘parent_id‘=>$id))->select();
                if(!is_null($childList)){
                    foreach($childList as $val){
                        $obj[‘childList‘][]=self::getCategoryTree($val[‘id‘]);
                    }
                }
            }
            if(isset($obj[‘childList‘])){
                //二维数组排序
                usort($obj[‘childList‘],function($a,$b){
                    $subtractRes=$a[‘order‘]-$b[‘order‘];
                    if($subtractRes<0){
                        return 1;
                    }elseif($subtractRes>0){
                        return -1;
                    }else{
                        return 0;
                    }
                });
            }
            return $obj;
        }else{
            $rootList=self::selectTable(‘category‘,array(‘parent_id‘=>$id));//$model->where(array(‘parent_id‘=>$id))->select();
            if(!is_null($rootList)){
                foreach($rootList as &$val){                    
                    $val=self::getCategoryTree($val[‘id‘]);
                }
            }
            return $rootList;
        }
    }

    //递归查找无限分类的父节点
    public static function getCategoryParent($categoryId){
        $category=self::selectTable(‘category‘,array(‘id‘=>$categoryId),true);// M(‘category‘)->where(array(‘id‘=>$categoryId))->find();
        if(!empty($category)){$category[‘parent‘]=self::getCategoryParent($category[‘parent_id‘]);
        }
        return $category;
    }

//从内存查询 表 以防止多次查库
    private static function selectTable($tableName,array $where,$getFirst=false){
        $res=array();
        if(!isset(self::$tableData[$tableName])){
            self::$tableData[$tableName]=M($tableName)->select();
        }
        if(false===self::$tableData[$tableName]){
            return false;
        }
        
        is_null(self::$tableData[$tableName]) and self::$tableData[$tableName]=array();        
        foreach(self::$tableData[$tableName] as $val){
            $flag=true;
            foreach($where as $k=>$v){
                if($val[$k]!=$v){
                    $flag=false;
                    break;
                }
            }            
            $flag and $res[]=$val;
        }
        $getFirst and $res=current($res);
        empty($res) and $res=null;
        return $res;
    }