本文实例讲述了php基于session实现数据库交互的类。分享给大家供大家参考。具体如下：

<?php/** * session 数据库存储类 */class Session { private static $session_id   = 0; private static $session_data  = array(); private static $is_update   = FALSE; private static $is_del    = FALSE; private static $is_gc    = FALSE; private static $dbo    = NULL;  //数据库连接句柄 private static $gc_max_time  = 1440; private static $table   = "sessions"; private static $pre_key   = "weige";//session 密钥 //捆绑使用哈 private static $gc_rate_de  = 100;//代表分母 private static $gc_rate_co  = 20;//代表分子 private static $path   = "/";//保存路径 private static $domain   = null; //域 private static $secure   = false;//默认 private static $httponly  = false;//默认 /**  * 获取数据库句柄 私有  */ private static function open()  {  if (!self::$dbo)   {   self::$dbo = Db::factory();  }  return TRUE; } /**  * 设置  * */ public static function set($key, $val=NULL)  {  self::open();  $data = self::read();  if ($data === FALSE)  {   $data = array();  }  if (!$val && is_array($key))  {   $data = $key;  }   else if ($val && is_string($key))  {   $data[$key] = $val;  }  self::write($data);  self::close(); } /**  *获取值   *   */ public static function get($key=NULL) {  self::open();  self::$session_data = self::read();  $ret = "";  if (!$key) {   $ret = self::$session_data;  } else if(is_array(self::$session_data) && isset(self::$session_data[$key])) {   $ret = self::$session_data[$key];  }  self::update();   self::close();  return $ret; } /**  * 删除或者重置  * */ public static function del($key) {  if (!self::$is_del)   {   self::open();   $val = self::read();   if (isset($val[$key]))    {    unset($val[$key]);   }   $session_id  = self::$session_id;   $session_data  = serialize($val);   $session_expire = TIME + self::get_gc_maxtime();   self::$dbo->query("update ".self::$table." set value="$session_data", expiry="$session_expire" where session_id="$session_id"");   self::close();  }  self::$is_del = TRUE; } /**  * 销毁  *   * */ public static function destroy()  {  $session_id   = self::get_session_id();  $_COOKIE["WBSID"] = "";  self::open();  self::$dbo->query("delete from ".self::$table." where session_id="$session_id"");  self::close(); } /**  * 读取 私有  * */ private static function read() {  $session_id = self::$session_id;  if (!$session_id) {   $session_id = self::get_session_id();  }  if (!$session_id) return array();  $user_agent = isset($_SERVER["HTTP_USER_AGENT"]) ? md5($_SERVER["HTTP_USER_AGENT"]) : "";  $client_ip = Fun::getIp();  $session_expire = TIME - self::get_gc_maxtime();  $rs = self::$dbo->fetchRow("select session_id, value, agent, ip from ".self::$table."   where session_id="$session_id" and expiry>"$session_expire"");  if (!$rs || $rs["agent"] != $user_agent || $rs["ip"] != $client_ip)   {   return FALSE;  }  self::$session_id = $rs["session_id"];  return unserialize($rs["value"]); } /**  * session 写入 私有  * */ private static function write(array $session_data)  {  $session_id = self::$session_id;  if (!$session_id)  {   $session_id = self::get_session_id();  }  $session_expire = TIME + self::get_gc_maxtime();  $user_agent = isset($_SERVER["HTTP_USER_AGENT"]) ? md5($_SERVER["HTTP_USER_AGENT"]) : "";  $client_ip  = Fun::getIp();  $session_data = serialize($session_data);  if (self::$session_id && self::$session_id === $session_id)   {   self::$dbo->query("update ".self::$table." set value="$session_data", expiry="$session_expire", agent="$user_agent", ip="$client_ip" where session_id="$session_id"");  }   else   {   self::$session_id = $session_id = self::create_session_id();   self::$dbo->query("insert into ".self::$table."(session_id, value, expiry, agent, ip)     values("$session_id", "$session_data", "$session_expire", "$user_agent", "$client_ip")");  }  return true; } /**  * session 更新 私有  * */ private static function update()  {  if (!self::$is_update)   {   $session_id = self::$session_id;   $session_expire = TIME + self::get_gc_maxtime();   self::$dbo->query("update ".self::$table." set expiry="$session_expire" where session_id="$session_id"");  }  self::$is_update = TRUE; } private static function close()  {  if (!self::$is_gc && mt_rand(1, self::$gc_rate_de)%self::$gc_rate_co == 0)   {   self::gc();  }  self::$is_gc = TRUE; } /**  * 过期session 清除 随机触发  * */ private static function gc()  {  $session_expire = TIME - self::get_gc_maxtime();   self::$dbo->query("delete from ".self::$table." where expiry<"$session_expire""); } private static function get_session_id()  {  if (isset($_COOKIE["WBSID"]) && strlen($_COOKIE["WBSID"])==32)   {   $sid = $_COOKIE["WBSID"];   setcookie("WBSID", $sid, TIME + self::get_gc_maxtime(), self::$path, self::$domain, self::$secure, self::$httponly);   return $sid;  }  return null; } private static function create_session_id()  {  $sid = self::get_session_id();  if (!$sid)   {   $sid = Fun::getIp() . TIME . microtime(TRUE) . mt_rand(mt_rand(0, 100), mt_rand(100000, 90000000));   $sid = md5(self::$pre_key . $sid);   setcookie("WBSID", substr($sid, 0, 32), TIME + self::get_gc_maxtime(), self::$path, self::$domain, self::$secure, self::$httponly);  }  return $sid; } public static function get_gc_maxtime() {  return self::$gc_max_time; }}

希望本文所述对大家的php程序设计有所帮助。