使用session_set_save_handler()函数，将Session的内容写入数据库
<?php
/*
*@author Fahy
*@link http://home.cnblogs.com/u/HuangWj
*数据库为mysql，
*数据库名为session，表名为session，
*表中字段包括PHPSESSID,update_time,client_ip,data
*/
class Session{
private static $handler = null;
private static $ip = null;
private static $lifetime = null;
private static $time = null; //配置静态变量
private static function init($handler){
self::$handler = $handler; //获取数据库资源
self::$ip = !empty($_SERVER["REMOTE_ADDR"])? $_SERVER["REMOTE_ADDR"]:'unkonw'; //获取客户端ip
self::$lifetime = ini_get('session.gc_maxlifetime'); //获取session生命周期
self::$time = time(); //获取当前时间
}
//调用session_set_save_handler()函数并开启session
static function start($pdo){
self::init($pdo);
session_set_save_handler(
array(__CLASS__,'open'),
array(__CLASS__,'close'),
array(__CLASS__,'read'),
array(__CLASS__,'write'),
array(__CLASS__,'destroy'),
array(__CLASS__,'gc')
);
session_start();
} public static function open($path,$name){
return true;
}
public static function close(){
return true;
} //查询数据库中的数据
public static function read($PHPSESSID){
$sql = "select PHPSESSID,update_time,client_ip,data from session where PHPSESSID=?";
$stmt = self::$handler->prepare($sql);
$stmt->execute(array($PHPSESSID));
if(!$result = $stmt->fetch(PDO::FETCH_ASSOC)){
return '';
}
if(self::$ip == $result['client_ip']){
self::destroy($PHPSESSID);
return '';
}
if(($result['update_time']+self::$lifetime)<self::$time){
self::destroy($PHPSESSID);
return '';
}
return $result['data'];
}
/*
*首先查询该session是否存在数据，如果存在，则更新数据，如果不存在，则插入数据
*/
//将session写入数据库中，$data传入session中的keys和values数组
public static function write($PHPSESSID,$data){
$sql = "select PHPSESSID,update_time,client_ip,data from session where PHPSESSID=?";
$stmt = self::$handler->prepare($sql);
$stmt->execute(array($PHPSESSID)); if($result=$stmt->fetch(PDO::FETCH_ASSOC)){
if($result['data'] != $data || self::$time > ($result['update_time']+30)){
$sql = "update session set update_time=?,data=? where PHPSESSID = ?";
$stmt = self::$handler->prepare($sql);
$stmt->execute(array($self::$time,$data,$PHPSESSID));
}
}else{
if(!empty($data)){
try{
$sql = "insert into session(PHPSESSID,update_time,client_ip,data) values(?,?,?,?)";
}catch(PDOException $e){
echo $e->getMessage();
}
$sth = self::$handler->prepare($sql);
$sth->execute(array($PHPSESSID,self::$time,self::$ip,$data));
}
}
return true;
} public static function destroy($PHPSESSID){
$sql = "delete from session where PHPSESSID = ?";
$stmt = self::$handler->prepare($sql);
$stmt->execute(array($PHPSESSID));
return true;
}
public static function gc($lifetime){
$sql = "delete from session where update_time<?";
$stmt = self::$handler->prepare($sql);
$stmt->execute(array(self::$time-$lifetime));
return true;
}
}
//使用PDO连接数据库
try{
$pdo = new PDO("mysql:host=localhost;dbname=session","root","hwj193");
}catch(PDOException $e){
echo $e->getMessage();
}
//传递数据库资源
Session::start($pdo);