使用session_set_save_handler()函数，将Session的内容写入数据库

  1 <?php  2     /*  3     *@author    Fahy  4     *@link    http://home.cnblogs.com/u/HuangWj  5     *数据库为MySQL，  6     *数据库名为session，表名为session，  7     *表中字段包括PHPSESSID,update_time,client_ip,data  8     */  9     class Session{ 10         PRivate static $handler = null; 11         private static $ip = null; 12         private static $lifetime = null; 13         private static $time = null; 14          15         //配置静态变量 16         private static function init($handler){ 17             self::$handler = $handler;        //获取数据库资源 18             self::$ip = !empty($_SERVER["REMOTE_ADDR"])? $_SERVER["REMOTE_ADDR"]:'unkonw';        //获取客户端ip 19             self::$lifetime = ini_get('session.gc_maxlifetime');        //获取session生命周期 20             self::$time = time();        //获取当前时间 21         } 22         //调用session_set_save_handler()函数并开启session 23         static function start($pdo){ 24             self::init($pdo); 25             session_set_save_handler( 26                 array(__CLASS__,'open'), 27                 array(__CLASS__,'close'), 28                 array(__CLASS__,'read'), 29                 array(__CLASS__,'write'), 30                 array(__CLASS__,'destroy'), 31                 array(__CLASS__,'gc') 32             ); 33             session_start(); 34         } 35          36         public static function open($path,$name){ 37             return true; 38         } 39         public static function close(){ 40             return true; 41         } 42          43         //查询数据库中的数据 44         public static function read($PHPSESSID){ 45              $sql = "select PHPSESSID,update_time,client_ip,data from session where PHPSESSID=?"; 46              $stmt = self::$handler->prepare($sql); 47              $stmt->execute(array($PHPSESSID)); 48              if(!$result = $stmt->fetch(PDO::FETCH_ASSOC)){ 49                  return ''; 50              } 51              if(self::$ip == $result['client_ip']){ 52                  self::destroy($PHPSESSID); 53                  return ''; 54              } 55              if(($result['update_time']+self::$lifetime)<self::$time){ 56                  self::destroy($PHPSESSID); 57                  return ''; 58              } 59              return $result['data']; 60         } 61         /* 62          *首先查询该session是否存在数据，如果存在，则更新数据，如果不存在，则插入数据 63          */ 64         //将session写入数据库中，$data传入session中的keys和values数组 65         public static function write($PHPSESSID,$data){ 66             $sql = "select PHPSESSID,update_time,client_ip,data from session where PHPSESSID=?"; 67              $stmt = self::$handler->prepare($sql); 68              $stmt->execute(array($PHPSESSID)); 69               70              if($result=$stmt->fetch(PDO::FETCH_ASSOC)){                 71                  if($result['data'] != $data || self::$time > ($result['update_time']+30)){ 72                      $sql = "update session set update_time=?,data=? where PHPSESSID = ?"; 73                      $stmt = self::$handler->prepare($sql); 74                      $stmt->execute(array($self::$time,$data,$PHPSESSID)); 75                 } 76              }else{ 77                  if(!empty($data)){ 78                      try{ 79                          $sql = "insert into session(PHPSESSID,update_time,client_ip,data) values(?,?,?,?)"; 80                      }catch(PDOException $e){ 81                          echo $e->getMessage(); 82                      } 83                      $sth = self::$handler->prepare($sql); 84                      $sth->execute(array($PHPSESSID,self::$time,self::$ip,$data)); 85                  } 86              } 87              return true; 88         } 89          90         public static function destroy($PHPSESSID){ 91             $sql = "delete from session where PHPSESSID = ?"; 92             $stmt = self::$handler->prepare($sql); 93             $stmt->execute(array($PHPSESSID)); 94             return true; 95         } 96         public static function gc($lifetime){ 97             $sql = "delete from session where update_time<?"; 98             $stmt = self::$handler->prepare($sql); 99             $stmt->execute(array(self::$time-$lifetime));100             return true;101         }102     }103     //使用PDO连接数据库104     try{105         $pdo = new PDO("mysql:host=localhost;dbname=session","root","hwj193");106     }catch(PDOException $e){107         echo $e->getMessage();108     }109     //传递数据库资源110     Session::start($pdo);