php設計模式 Factory(工廠模式)

復制代碼 代碼如下:
<?php
/**
* 工廠方法模式
*
* 定義一個用於創建對象的接口,讓子類決定將哪一個類實例化,使用一個類的實例化延遲到其子類
*/

/*
class DBFactory
{
public static function create($type)
{
swtich($type)
{
case "Mysql":
return new MysqlDB(); break;
case "Postgre":
return new PostgreDB(); break;
case "Mssql":
return new MssqlDB(); break;
}
}
}
*/
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");