用session_set_save_handler函数实现将session保存在数据库中后session不能跨页面了_html/css_WEB-ITnose

db = &$db;        session_module_name('user'); //session文件保存方式，这个是必须的！除非在Php.ini文件中设置了        session_set_save_handler(             array(&$this, 'open'), //在运行session_start()时执行            array(&$this, 'close'), //在脚本执行完成或调用session_write_close() 或 session_destroy()时被执行,即在所有session操作完后被执行            array(&$this, 'read'), //在运行session_start()时执行,因为在session_start时,会去read当前session数据            array(&$this, 'write'), //此方法在脚本结束和使用session_write_close()强制提交SESSION数据时执行            array(&$this, 'destroy'), //在运行session_destroy()时执行            array(&$this, 'gc') //执行概率由session.gc_probability 和 session.gc_divisor的值决定,时机是在open,read之后,session_start会相继执行open,read和gc        );         session_start(); //这也是必须的，打开session，必须在session_set_save_handler后面执行    }       function unserializes($data_value) {         $vars = preg_split(             '/([a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*)\|/',             $data_value, -1, PREG_SPLIT_NO_EMPTY |             PREG_SPLIT_DELIM_CAPTURE         );         for ($i = 0; isset($vars[$i]); $i++) {             $result[$vars[$i++]] = unserialize($vars[$i]);         }         return $result;     }     function open($path, $name) {         return true;     }     function close() { 	    $this->gc($this->lasttime);        return true;     }    function read($SessionKey){	    $sql = "SELECT uid FROM sessions WHERE session_id = '".$SessionKey."' limit 1"; 		$query =$this->db->query($sql);		if($row=$this->db->fetch_array($query)){		  return $row['uid'];		}else{            return ""; 		}		    }     function write($SessionKey,$VArray) { 	   require_once(MRoot.DIR_WS_CLASSES .'db_mysql_class.php');	   $db1=new DbCom();	  // make a connection to the database... now	   $db1->connect(DB_SERVER, DB_SERVER_USERNAME, DB_SERVER_PASSWORD, DB_DATABASE);	   $db1->query("set names utf8");	   $this->db=$db1;       $SessionArray = addslashes($VArray);		$data=$this->unserializes($VArray);	  	    	 		$sql0 = "SELECT uid FROM sessions WHERE session_id = '".$SessionKey."' limit 1"; 		$query0 =$this->db->query($sql0);		if($this->db->num_rows($query0)db->query("insert into `sessions` set `session_id` = '$SessionKey',uid='".$data['webid']."',last_visit='".time()."'");			} 		  			return true;		}else{			/*$sql = "update `sessions` set "; 			if(isset($data['webid'])){			$sql .= "uid = '".$data['webid']."', " ;			}			$sql.="`last_visit` = null " 				  . "where `session_id` = '$SessionKey'"; 				 			$this->db->query($sql); */			return true; 		}	    }   function destroy($SessionKey) {      $this->db->query("delete from `sessions` where `session_id` = '$SessionKey'");      return true;    }    function gc($lifetime) {       $this->db->query("delete from `sessions` where unix_timestamp(now()) -`last_visit` > '".$this->lasttime."'");       return true;   }   } ?>