本文实例讲述了PHP封装的数据库保存session功能类。分享给大家供大家参考，具体如下：

PHP用数据库保存session类：

<?php

class SafeSessionHandler implements SessionHandlerInterface {

  public $save_path;

  public $session_name;

  public $table;

  public function __construct() {

    $this->table = new Table("safe_session");

  }

  private function session_id_parse($session_id) {

    $time = hexdec(substr($session_id, 0, 8));

    $skey = substr($session_id, 8);

    return array($time, $skey);

  }

  public function close() {

    loginfo("close: ");

    return true;

  }

  public function create_sid() {

    loginfo("create_sid: ");

    $time = time();

    $skey = "";

    $char = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";

    for ($i=0; $i<52; $i++) {

      $skey .= $char{mt_rand(0, 61)};

    }

    $session = array(

      "time" => $time,

      "skey" => $skey,

      "sval" => "",

    );

    $this->table->insert($session);

    return dechex($time) . $skey;

  }

  public function destroy($session_id) {

    loginfo("destroy: %s", $session_id);

    list($time, $skey) = $this->session_id_parse($session_id);

    $this->table->where("time = ?", $time)->where("skey = ?", $skey)->delete();

    return true;

  }

  public function gc($maxlifetime) {

    loginfo("gc: %s", $maxlifetime);

    $this->table->where("time < ?", time() - 86400 * 30)->delete();

    return true;

  }

  public function open($save_path, $session_name) {

    loginfo("open: %s, %s", $save_path, $session_name);

    $this->save_path = $save_path;

    $this->session_name = $session_name;

    return true;

  }

  public function read($session_id) {

    loginfo("read: %s", $session_id);

    list($time, $skey) = $this->session_id_parse($session_id);

    $row = $this->table->where("time = ?", $time)->where("skey = ?", $skey)->select()->fetch();

    if (empty($row)) {

      return "";

    }

    return $row["sval"];

  }

  public function write($session_id, $session_data) {

    loginfo("write: %s, %s", $session_id, $session_data);

    $session = array("sval" => $session_data,);

    list($time, $skey) = $this->session_id_parse($session_id);

    $this->table->where("time = ?", $time)->where("skey = ?", $skey)->update($session);

    return true;

  }

}

希望本文所述对大家PHP程序设计有所帮助。