PHP中SESSION自定义会话管理器

<?phpclass CustomSession implements SessionHandlerInterface{ ?????private $link; ?????private $lifetime; ?????public function open($savePath,$session_name){ ?????????$this->lifetime=get_cfg_var(‘session.gc_maxlifetime‘); ?????????$this->link=mysqli_connect(‘localhost‘,‘root‘,‘root‘,‘session_test‘); ?????????mysqli_query($this->link,"SET names UTF8"); ?????????if($this->link){ ?????????????return true; ?????????} ?????????return false; ?????} ?????public function close(){ ?????????????mysqli_close($this->link); ?????????????return true; ?????} ?????public function read($session_id){ ?????????????$sql="SELECT *from sessions where session_id=‘{$session_id}‘ ?????????????and session_expires >".time(); ?????????????$result=mysqli_query($this->link,$sql); ?????????????if(mysqli_num_rows($result)){ ?????????????????return mysqli_fetch_array($result)[‘session_data‘]; ?????????????} ?????????????return ""; ?????} ?????public function write($session_id,$session_data){ ?????????????$newExp=time()+$this->lifetime; ?????????????//首先查询是否存在指定的session_id,如果存在相当于更新数据，否则是第一次，则写入数据 ?????????????$sql="SELECT * from sessions where session_id={‘$session_id‘}"; ?????????????$result=mysqli_query($this->link,$sql); ?????????????if(mysqli_num_rows($result)==1){ ?????????????????$sql="UPDATE sessions set session_expires=‘{$newExp}‘,session_data=‘{$session_data}‘ ??????????????????where ?session_id=‘{$session_id}‘ "; ?????????????}else{ ?????????????????$sql="INSERT into sessions values(‘{$session_id}‘,‘$session_data‘,‘{$newExp}‘)"; ?????????????} ?????????????mysqli_query($this->link,$sql); ?????????????return mysqli_affected_rows($this->link)==1; ?????} ?????????????public function destroy($session_id){ ?????????????$sql="DELETE from sessions where session_id=‘{$session_id}‘"; ?????????????mysqli_query($this->link,$sql); ?????????????return mysqli_affected_rows($this->link)==1; ?????} ?????public function gc($maxlifetime){ ?????????????$sql="DELETE from sessions where session_expires<".time(); ?????????????mysqli_query($this->link,$sql); ?????????????if(mysqli_affected_rows($this->link)>0){ ?????????????????return true; ?????????????} ?????????????return false; ?????}}

<?php ????header("Content-type:text/html;charset=utf-8"); ???require_once ‘customSession.php‘; ???$customSession=new CustomSession(); ???ini_set(‘session.save_handler‘, ‘user‘); ???session_set_save_handler($customSession,true); ???session_start(); ???$_SESSION[‘name‘]=‘admin‘; ???$_SESSION[‘pwd‘]=‘123456‘;

//销毁会话，从数据库中删除<?php ????require_once ‘customSession.php‘; ???$customSession=new CustomSession(); ???ini_set(‘session.save_handler‘, ‘user‘); ???session_set_save_handler($customSession,true); ???session_start(); ???session_destroy();