php设计模式学习之工厂模式

我的认为:所为工厂模式是事先有一系类class,一个工厂类'

工厂类根据不同的参数创建不同的对象,调用各自的方法;

php利用工厂模式实现计算器:

?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.