php设计模式梳理-工厂方法

//公共接口
interface db(){
    function conn();
}

interface Factory{
    function createDB();
}

//服务端
class dbmysql implements db {
    public function conn(){
        echo '连接上了mysql';
    }
}

class dbsqlite implements db {
    public function conn(){
        echo '连接上了sqlite';
    }
}

class mysqlFactory implements Factory {
    public function createDB(){
        return new dbmysql();
    }
}

class sqliteFactory implements Factory {
    public function createDB(){
        return new dbsqlite();
    }
}

class dboracle implements db {
    public function conn(){
        echo '连接上了oracle';
    }
}  

class oracleFactory implements Factory {
    public function createDB(){
        return new dboracle();
    }
}

$fact = new mysqlFactory();
$db = $fact->createDB();
$db->conn();

$fact = new sqliteFactory();
$db = $fact->createDB();
$db->conn();

$fact = new oracleFactory();
$db = $fact->createDB();
$db->conn();