php session 写入数据库

<"session.gc_maxlifetime");
    session_set_save_handler(
    array($this, "open"),
    array($this, "close"),
    array($this, "read"),
    array($this, "write"),
    array($this, "destroy"),
    array($this, "gc"));
     
  }
   
  public function open() {
    $this->link = mysqli_connect(
    $this->config['host'], 
    $this->config['user'], 
    $this->config['password'], 
    $this->config['database']);
    mysqli_set_charset($this->link, "utf8");
    $sql = 'CREATE TABLE IF NOT EXISTS `%s` (
    `session_id` varchar(255) NOT NULL,
    `session_data` text,
    `session_expires` char(10) NOT NULL,
    PRIMARY KEY (`session_id`)
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;';
    $sql = sprintf($sql, $this->config['table']);
    mysqli_query($this->link, $sql);
    return true;
  }
   
  public function close() {
    return true;
  }
   
   
  public function read($session_id) {
    if(empty($session_id)) return null;
     
    $sql = 'SELECT `session_data` AS `data` FROM `%s` WHERE `session_id` = "%s" AND `session_expires` > "%u"';
    $sql = sprintf($sql, 
    mysqli_real_escape_string($this->link, $this->config['table']), 
    mysqli_real_escape_string($this->link, $session_id),
    time());
     
    $result = mysqli_query($this->link, $sql);
    $row = mysqli_fetch_assoc($result);
    return $row['data'];
     
  }
   
  public function write($session_id, $session_data) {
    if(empty($session_id)) return null;
     
    $newExpires = time() + $this->maxlifetime;
    $sql = 'REPLACE INTO `%s` SET `session_id` = "%s", `session_data` = "%s", `session_expires` = "%u"';
    $sql = sprintf($sql, 
    mysqli_real_escape_string($this->link, $this->config['table']), 
    mysqli_real_escape_string($this->link, $session_id),
    mysqli_real_escape_string($this->link, $session_data),
    $newExpires);
     
    $result = mysqli_query($this->link, $sql);
    return mysqli_affected_rows($this->link);
     
  }
   
  public function destroy($session_id) {
    $sql = 'DELETE FROM `%s` WHERE `session_id` = "%s"';
    $sql = sprintf($sql, 
    mysqli_real_escape_string($this->link, $this->config['table']), 
    mysqli_real_escape_string($this->link, $session_id));
 
    $result = mysqli_query($this->link, $sql);
    return mysqli_affected_rows($this->link);
  }
   
  public function gc() {
    $sql = 'DELETE FROM `%s` WHERE `session_expires` < "%u"';
    $sql = sprintf($sql, 
    mysqli_real_escape_string($this->link, $this->config['table']), 
    time());
     
    $result = mysqli_query($this->link, $sql);
    return mysqli_affected_rows($this->link);
  }
   
}
 
class session {
 
  public static $collection = null;
   
  public static function open($clean = false, $token = false) {
    if($clean) ob_end_clean();
    if($token) session_id($token);
    session_start();
    self::$collection = $_SESSION;
  }
   
  public static function id() {
    $num_args = func_num_args();
    if($num_args) {
      $args = func_get_arg(0);
      return session_id($args);
    }else{
      return session_id();
    }
  }
   
  public static function get($name) {
    return isset($_SESSION[$name]) "host"=> "127.0.0.1",
"user"=> "root",
"password"=> "123456",
"database"=> "test",
"charset"=> "utf8",
"table"=> "user_session");
 
session_handler::init($config);
session::open();
session::set("profile", array("id"=> 1, "user"=> "haowei", "vip-level"=> 6));