src/DB/Connecter/MySQLConnecter.php
static function getInstance($dsn, $user, $password, array $option = array())
    {
        //同时建立多个连接时候已dsn的md5值为key
        $key = md5($dsn);
        if (!isset(self::$instance[$key])) {
            self::$instance [$key] = new self($dsn, $user, $password, $option);
        }

        return self::$instance [$key];
    }
static function getInstance($dsn, $user, $password, array $option = array())
    {
        //同时建立多个连接时候已dsn的md5值为key
        $key = md5($dsn);
        if (!isset(self::$instance[$key])) {
            self::$instance [$key] = new self($dsn, $user, $password, $option);
        }

        return self::$instance [$key];
    }
@see MysqlModel::__construct

@param string $dsn
@param string $user
@param string $password
@param array $option
@return mixed
@throws CoreException