PHP设计模式之工厂模式

<?php
/**
 * 工厂方法模式
 *
 * 定义一个用于创建对象的接口,让子类决定将哪一个类实例化,使用一个类的实例化延迟到其子类
*/

class DBFactory
{
        public static function create($type)
        {
                $class = $type . "DB";
                return new $class;
        }
}

interface DB
{
        public function connect();
        public function exec();
}

class MysqlDB implements DB
{
        public function __construct() {
                echo"mysql db<br/>";
    }

        public function connect() {}

        public function exec() {}
}

class PostgreDB implements DB
{
        public function __construct() {
                echo"Postgre db<br/>";
        }

        public function connect() {}
        
        public function exec() {}
}

class MssqlDB implements DB
{
        public function __construct() {
                echo"mssql db<br/>";
        }

        public function connect() {}
        public function exec() {}
}

$oMysql= DBFactory::create("Mysql");
$oPostgre= DBFactory::create("Postgre");
$oMssql= DBFactory::create("Mssql");