php使用MySQL保存session会话

//////使用MySQL保存会话首先要创建session表：
 
<?php
$hostname_login = "localhost";          // Server address
$username_login = "root";            // User name 
$password_login = "";              // Password
 
//
$data_name = "session";            // Database name
 
 
$login = mysql_pconnect($hostname_login, $username_login, $password_login) or trigger_error(mysql_error(),E_USER_ERROR); 
$sql="SHOW DATABASES LIKE '".$data_name."'";    // If it is exist
if($rs_table=mysql_query($sql,$login)) { 
   if($rs_value=mysql_fetch_array($rs_table)) { 
     echo "数据库已经存在！\n!";
     exit(); 
   } 
}
 
$sql="CREATE DATABASE $data_name";     
mysql_query($sql);                 // Crate database
echo "数据库创建成功！\n"; 
mysql_select_db($data_name, $login);
 
$sql="CREATE TABLE `sessions` ( 
`SessionKey` varchar(32) NOT NULL default '', 
`SessionArray` blob NOT NULL, 
`SessionExpTime` int(20) unsigned NOT NULL default '0', 
PRIMARY KEY (`SessionKey`), 
KEY `SessionKey` (`SessionKey`) 
) ENGINE=MyISAM DEFAULT CHARSET=utf8"; //新建数据库 sql语句
mysql_query($sql);
echo "成功新建数据库表！";
 
?>
 
 
/////////MysqlSession 类如下：
 
<?php    
class MysqlSession {       // 注意在有使用Session的页面。页面一定要顶格，页面开始处不能留空。
private $DB_SERVER = "localhost";   // 数据库服务器主机名
    private $DB_NAME = "";    // 数据库名字
    private $DB_USER = "root";     // MYSQL 数据库访问用户名 
    private $DB_PASS = "";      // MYSQL 数据库访问密码 
      
    private $DB_SELECT_DB = ""; 
//private $SESS_LIFE = 1440;     // Session的最大使用时长，单位秒。
private $SESS_LIFE = 0;
 
function MysqlSession (&$sessionDB) {
   //session_write_close();
   $this->DB_NAME = &$sessionDB;
   $this->SESS_LIFE = get_cfg_var("session.gc_maxlifetime");
   session_module_name('user');
   session_set_save_handler( 
    array(&$this, 'sess_open'), 
    array(&$this, 'sess_close'), 
    array(&$this, 'sess_read'), 
    array(&$this, 'sess_write'), 
    array(&$this, 'sess_destroy'), 
    array(&$this, 'sess_gc') 
   );
 
   session_start();
}
      
function sess_open($save_path, $session_name){   // 打开数据库连接
   if (! $this->DB_SELECT_DB = mysql_pconnect($this->DB_SERVER, $this->DB_USER, $this->DB_PASS)) { 
    echo "SORRY! MYSQL ERROR : Can't connect to $this->DB_SERVER as $DB_USER"; 
    echo "MySQL Error: ", mysql_error(); 
    die; 
   } 
    
   if (! mysql_select_db($this->DB_NAME, $this->DB_SELECT_DB)) { 
    echo "SORRY! MYSQL ERROR : Unable to select database $this->DB_NAME"; 
    die; 
   } 
   return true; 
} 
    
function sess_close() { 
       return true; 
} 
    
function sess_read($SessionKey){   
        $Query = "SELECT SessionArray FROM sessions WHERE SessionKey = '".$SessionKey."' AND SessionExpTime > " . time(); // 过期不读取。
        $Result = mysql_query($Query, $this->DB_SELECT_DB); 
   if (list($SessionArray) = mysql_fetch_row($Result)) { 
         return $SessionArray; 
   } 
   return false; 
} 
    
function sess_write($SessionKey, $VArray) { 
    $SessionExpTime = time() + $this->SESS_LIFE; // 更新Session过期时间，Session过期时间 = 最后一次更新时间 + Session的最大使用时长
    $SessionArray = addslashes($VArray); 
    $Query = "INSERT INTO sessions (SessionKey,SessionExpTime,SessionArray) VALUES ('".$SessionKey."','".$SessionExpTime."','".$SessionArray."')"; 
    $Result = mysql_query($Query, $this->DB_SELECT_DB); 
    if (!$Result){ 
           $Query = "UPDATE sessions SET SessionExpTime = '".$SessionExpTime."', SessionArray = '".$SessionArray."' WHERE SessionKey = '".$SessionKey."' AND   SessionExpTime > " . time(); 
           $Result = mysql_query($Query, $this->DB_SELECT_DB); 
    }    
    return $Result; 
} 
     
function sess_destroy($SessionKey) { 
   $Query = "DELETE FROM sessions WHERE SessionKey = '".$SessionKey."'"; 
   $Result = mysql_query($Query, $this->DB_SELECT_DB); 
   return $Result; 
} 
    
function sess_gc($maxlifetime) { // 这个垃圾清除器系统调用。默认是1440秒清除一次。参数可以在PHP.ini里面设置。
   $Query = "DELETE FROM sessions WHERE SessionExpTime < " . time(); 
   $Result = mysql_query($Query, $this->DB_SELECT_DB); 
   return mysql_affected_rows($this->DB_SELECT_DB); 
} 
    
}
 
 
?>
 
//用法：在原来使用 session_start 的地方，替换成 $session = new MysqlSession () 
//注意：包含此程序前要打开数据库，主程序退出前不能关闭数据库，否则会出错。