php设计模式学习之工厂模式

?php
/**
* Created by PhpStorm.
* User: modern
* Date: 16-7-19
* Time: 下午5:24
* 简单工厂模式两数运算器
*/

echo "hello factory models<br/>";
echo "begin<br/>";

if(isset($_GET['param1'])){
$param1 = $_GET['param1'];
}else{
$param1 = 0;
}
if(isset($_GET['param2'])){
$param2 = $_GET['param2'];
}else{
$param2 = 0;
}

if(isset($_GET['param3'])){
$param3 = $_GET['param3'];
}else{
$param3 = '';
}

interface Init
{
public function getResult($a,$b);
}

class OperateAdd implements Init
{
public function getResult($a,$b)
{
return $a + $b;
}
}

class OperateSub implements Init
{
public function getResult($a,$b)
{
return $a - $b;
}
}

class OperateMul implements Init
{
public function getResult($a,$b)
{
return $a * $b;
}
}
class OperateDiv implements Init
{
public function getResult($a,$b)
{
try{
if($b == 0){
throw new Exception("除数不能为0");
}else{
return $a / $b;
}
}catch (\Exception $e){
echo "运算发生错误:".$e->getMessage();
}
}
}

class Calc
{
public static function operate($operate)
{
try{
switch($operate)
{
case '+':
return new OperateAdd();break;
case '-':
return new OperateSub();break;
case '*':
return new OperateMul();break;
case '/':
return new OperateDiv();break;
default:
throw new Exception("标识错误!");
}
}catch (\Exception $e){
echo '运算错误:'.$e->getMessage();
}
}
}
$me = Calc::operate($param3);
if(gettype($me) == 'object'){
$result = $me->getResult($param1,$param2);
echo $result;
}

解说:本例中,定义接口类init,再定义加减乘除四个类分别实现这个接口类,这样每个运算方法都须事先方法getResult(),定义工厂类,工厂类里定义一个静态方法,用户根据不同参数创建各个方法对象.最后再调用getResult()实现运算.