session.save_handler = redis
session.save_path = "tcp://127.0.0.1:6379"

ini_set('session.save_handler','redis');
ini_set('session.save_path','tcp://127.0.0.1:6379');

session.save_handler = redis
session.save_path = "tcp://127.0.0.1:6379?auth=authpwd"

session.save_path = "xxxx"

<?php
class sessionHandler{/*** session 存放的库*/const SESSION_DB = 'mytest';/*** session 存放的表*/const SESSION_TABLE = 'session';/*** @var string $_dbHandler 数据库链接句柄*/private $_dbHandler;/*** @var string $_dbHost 数据库主机*/private $_dbHost;/*** @var string $_dbUser 数据库用户名*/private $_dbUser;/*** @var string $_dbUser 数据库密码*/private $_dbPasswd;/*** @var string $_name session 名称*/private $_name;/*** 构造函数* @param string $dbHost 数据库主机* @param string $dbUser 数据库用户名* @param string $dbPasswd 数据库密码* @return void*/public function __construct($dbHost, $dbUser, $dbPasswd){$this->_dbHost = $dbHost;$this->_dbUser = $dbUser;$this->_dbPasswd = $dbPasswd;}/*** 链接数据库* @param string $savePath 存储路径* @param string $name 名称* @return boolean*/public function open($savePath, $name){$this->_dbHandler = mysql_connect($this->_dbHost, $this->_dbUser, $this->_dbPasswd);if(!$this->_dbHandler){return false;}$this->_name = $name;mysql_select_db(self::SESSION_DB, $this->_dbHandler);return true;}/*** 读session* @param string $sessionId session id* @return mixd 存在返回数组  否则返回空*/public function read($sessionId){$data = '';$sql = sprintf('SELECT `data` FROM ' . self::SESSION_TABLE . ' WHERE `id`="%s"', $sessionId);$result = mysql_query($sql, $this->_dbHandler);if(mysql_num_rows($result) == 1){list($data) = mysql_fetch_array($result, MYSQL_NUM);}return $data;}/*** 链接数据库* @param string $sessionId session id* @param string $data 数据* @return boolean*/public function write($sessionId, $data){$sql = sprintf('REPLACE INTO ' . self::SESSION_TABLE . ' (`id`, `data`, `last_time`) VALUES ("%s", "%s", %d)', $sessionId,     mysql_escape_string($data),  time());mysql_query($sql, $this->_dbHandler);return mysql_affected_rows($this->_dbHandler) > 0;}/*** 链接数据库* @param int $expire 生存周期* @return boolean*/public function gc($expire){$sql = sprintf('DELETE FROM `' . self::SESSION_TABLE . '`WHERE `last_time` < NOW() - %d',$expire);mysql_query($sql, $this->_dbHandler);return mysql_affected_rows($this->_dbHandler) > 0;}/*** 关闭数据库链接* @param void* @return boolean*/public function close(){return mysql_close($this->_dbHandler);}/*** 销毁session* @param string $sessionId* @return boolean*/public function destroy($sessionId){$sql = sprintf('DELETE FROM `' . self::SESSION_TABLE . '` WHERE `id`="%s"', $sessionId);mysql_query($sql, $this->_dbHandler);$_SESSION = array();return mysql_affected_rows($this->_dbHandler) > 0;}
}$sessionHandler = new sessionHandler('localhost', 'root', '123abc+');
session_set_save_handler(array($sessionHandler, 'open'),array($sessionHandler, 'close'),array($sessionHandler, 'read'),array($sessionHandler, 'write'),array($sessionHandler, 'destroy'),array($sessionHandler, 'gc'));/*在 PHP 5.0.5 中，在对象销毁之后才会调用 write 和 close 回调函数， 所以，在这两个回调函数中不可以使用对象，也不可以抛出异常。 如果在函数中抛出异常，PHP 既不会捕获它，也不会跟踪它， 这样会导致程序异常终止。 但是对象析构函数可以使用会话。可以在析构函数中调用 session_write_close() 函数来解决这个问题。 但是注册 shutdown 回调函数才是更加可靠的做法
*/
register_shutdown_function('session_write_close');session_start();
$_SESSION['test'] = 'aa';