PHP将session信息存储到数据库的类实例

本文实例讲述了PHP将session信息存储到数据库的类。分享给大家供大家参考。具体分析如下：

SessionHandlerInterface接口是PHP内置的接口，直接实现就行了
具体可以看php手册关于session_set_save_handler函数的解释！

PHP代码如下：

/**

* session信息存储到数据库的类

* 表结构：

* CREATE TABLE IF NOT EXISTS `sessioninfo` (

*  `sid` varchar(255) NOT NULL,

*  `value` text NOT NULL,

*  `expiration` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,

*  PRIMARY KEY (`sid`)

* ) ENGINE=InnoDB DEFAULT CHARSET=utf8;

*/

class MySessionHandler implements SessionHandlerInterface {

    /**

    * @access private

    * @var object 数据库连接

    */

    private $_dbLink;

    /**

    * @access private

    * @var string 保存session的表名

    */

    Private $_sessionTable;

    /**

    * @access private

    * @var string session名

    */

    private $_sessionName;

    /**

    * @const 过期时间

    */

    const SESSION_EXPIRE = 10;

    public function __construct($dbLink, $sessionTable) {

        if(!is_object($dbLink)) {

            return false;

        }

        $this->_dbLink = $dbLink;

        $this->_sessionTable = $sessionTable;

    }

    /**

    * 打开

    * @access public

    * @param string $session_save_path 保存session的路径

    * @param string $session_name session名

    * @return integer

    */

    public function open($session_save_path, $session_name) {

        $this->_sessionName = $session_name;

        return 0;

    }

    /**

    * 关闭

    * @access public

    * @return integer

    */

    public function close() {

        return 0;

    }

    /**

    * 关闭session

    * @access public

    * @param string $session_id session ID

    * @return string

    */

    public function read($session_id) {

        $query = "SELECT value FROM {$this->_sessionTable} WHERE sid = {$session_id} AND UNIX_TIMESTAMP(expiration) + " . self::SESSION_EXPIRE . " > UNIX_TIMESTAMP(NOW())";

        $result = $this->_dbLink->query($query);

        if(!isset($value) || empty($value)) {

            $value = "";

            return $value;

        }

        $this->_dbLink->query("UPDATE {$this->_sessionTable} SET expiration = CURRENT_TIMESTAMP() WHERE sid = {$session_id}");

        $value = $result->fetch_array();

        $result->free();

        return $value['value'];

    }

    /**

    * 写入session

    * @access public

    * @param string $session_id session ID

    * @param string $session_data session data

    * @return integer

    */

    public function write($session_id, $session_data) {

        $query = "SELECT value FROM {$this->_sessionTable} WHERE sid = '{$session_id}' AND UNIX_TIMESTAMP(expiration) + " . self::SESSION_EXPIRE . " > UNIX_TIMESTAMP(NOW())";

        $result = $this->_dbLink->query($query);

        $result = $result->fetch_array();

        if(!empty($result)) {

            $result = $this->_dbLink->query("UPDATE {$this->_sessionTable} SET value = {$session_data} WHERE sid = {$session_id}");

        }

        else{

            $result = $this->_dbLink->query("INSERT INTO {$this->_sessionTable} (sid, value) VALUES ('{$session_id}', '{$session_data}')");

        }

        if($result){

            return 0;

        }

        else{

            return 1;

        }       

    }

    /**

    * 销魂session

    * @access public

    * @param string $session_id session ID

    * @return integer

    */

    public function destroy($session_id) {

        $result = $this->_dbLink->query("DELETE FROM {$this->_sessionTable} WHERE sid = '{$session_id}'");

        if($result){

            return 0;

        }

        else{

            return 1;

        }

    }

    /**

    * 垃圾回收

    * @access public

    * @param string $maxlifetime session 最长生存时间

    * @return integer

    */

    public function gc($maxlifetime) {

        $result = $this->_dbLink->query("DELETE FROM {$this->_sessionTable} WHERE UNIX_TIMESTAMP(expiration) < UNIX_TIMESTAMP(NOW()) - " . self::SESSION_EXPIRE);

        if($result){

            return 0;

        }

        else{

            return 1;

        }

    }

}

$dbLink = new mysqli("localhost", "root", "root", "test");

$sessionTable = "sessioninfo";

$handler = new MySessionHandler($dbLink, $sessionTable);

session_set_save_handler($handler);

session_start();

$_SESSION['name'] = "test";

echo $_SESSION["name"];

//session_destroy();

希望本文所述对大家的php程序设计有所帮助。