session 入库

<?phpini_set("session.save_handler","user");//ini_set("session.gc_probability",1);//ini_set("session.gc_divisor",2);session_set_save_handler("open","close",'read',"write","destroy","gc");//连接数据库function open(){    mysql_connect("127.0.0.1","root","root");    mysql_query("set names utf8");    mysql_query("use test");}function close(){    mysql_close();}function read($sess_id){    $sql="select session_data from `session` where  session_id='$sess_id'";    $result=mysql_query($sql);    if($rows = mysql_fetch_assoc($result)){        return $rows['session_data']; }    else{        return '';    }}function write($sess_id,$sess_data){    $sql="select * from `session` where session_data='$sess_data'";    $re=mysql_query($sql);    $ass=mysql_fetch_assoc($re);    if($ass){        $sql="update `session` set session_id='$sess_id', `time`=now() where session_data='$sess_data' ";        return mysql_query($sql);    }else{        $sql = "insert into `session` (session_id,session_data,`time`) values('$sess_id','$sess_data', now()) on duplicate key update session_data = '$sess_data' , `time` = now()";  //这是为了gc()        return mysql_query($sql);    }}function destroy($sess_id){    echo __FUNCTION__;    $sql = "delete from `session` where session_id = '$sess_id'";    return mysql_query($sql);}function gc($sess_id){    $maxlifetime = ini_set("session.gc_maxlifetime");    echo __FUNCTION__;    $sql = "delete from `session` where now()-`time` > '$maxlifetime' ";    return mysql_query($sql);}header("content-type:text/html;charset=utf8");session_start();$_SESSION['name']="lisi";echo session_id();echo $_SESSION['name'];