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PHP之设计模式（工厂、单例）

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Libérer： 2016-07-29 09:02:23

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设计模式简单说应对某类问题而设计的解决方式

工厂模式：应对需求创建相应的对象

<code><span><span>class</span><span>factory</span>{</span><span><span>function</span><span>__construct</span><span>(<span>$name</span>)</span>{</span><span>if</span>(file_exists(<span>'./'</span>.<span>$name</span>.<span>'.class.php'</span>)){
            <span>return</span><span>new</span><span>$name</span>;
        }<span>else</span>{
            <span>die</span>(<span>'not exist'</span>);
        }
    }
}</code>

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单例模式：只创建一个对象的实例，不允许再创建实例，节约资源（例如数据库的连接）

<code><span><span>class</span><span>instance</span>{</span><span>public</span><span>$val</span> = <span>10</span>;
    <span>private</span><span>static</span><span>$instance</span> ;
    <span>private</span><span><span>function</span><span>__construct</span><span>()</span>{</span>}
    <span>private</span><span><span>function</span><span>__clone</span><span>()</span>{</span>}
    <span>//设置为静态方法才可被类调用</span><span>public</span><span>static</span><span><span>function</span><span>getInstance</span><span>()</span>{</span><span>/*if(!isset(self::$instance)){
            self::$instance = new self;
        }*/</span><span>if</span>(!<span>isset</span>(instance::<span>$instance</span>)){
            instance::<span>$instance</span> = <span>new</span><span>self</span>;
        }
        <span>return</span> instance::<span>$instance</span>;
    }
}

<span>$obj_one</span> = instance::getInstance();
<span>$obj_one</span>->val = <span>20</span>;
<span>//clone可以调用__clone()克隆即new出一个新的的对象</span><span>//$obj_two = clone $obj_one;</span><span>$obj_two</span> = instance::getInstance();
<span>echo</span><span>$obj_two</span>->val;
<span>echo</span><span>'<p>'</p></span>;
var_dump(<span>$obj_one</span>,<span>$obj_two</span>);</code>

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PHP之设计模式（工厂、单例）

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以上就介绍了PHP之设计模式（工厂、单例），包括了方面的内容，希望对PHP教程有兴趣的朋友有所帮助。