PHP设计模式--工厂模式

createDB();$db->conn();echo '
';//连接Sqlite$fact = new SqliteFactory();$db = $fact->createDB();$db->conn();echo '
';/** * 扩展：添加Oracle连接 */class OracleDB implements Db{    function conn() {        echo '连接上Oracle....';    }}class OracleFactory implements Factory{    public function createDB() {        return new OracleDB();    }}//连接Oracle$fact = new OracleFactory();$db = $fact->createDB();$db->conn();echo '
';