<?php     private  function _deleteSubNode($ids){         $subNodes = array();         $mod = D('Node');         foreach (explode ( ',', $ids ) as $k){             $res = $this->_getSubNode($k,$subNodes[$k],$mod);  //获取子节点             if(!empty($res[0])){                 foreach($res as $k => $nid){                     $mod->where('id = '.$nid)->delete();       //删除子节点                 }             }         }         return ;     }     private function _getSubNode($id, &$arr,$mod){          $condition = array ('pid' => array ('eq', $id ));          $ret = $mod->where($condition)->getField('id');          if(!empty($ret[0])){              foreach ($ret as $k => $node){                  $arr[] = $node['id'];                  $this->_getSubNode($node['id'], $arr, $mod);             }          }          return $arr;     } ?>