php 魔術方法 __sleep __wakeup __toString __debuginfo

__sleep():

使用serialize()序列化的時候，會偵測類別中是否有__sleep()魔術方法，有的話會先呼叫__sleep()，傳回一個包含物件中所有需要序列化的變數名稱的陣列

<code><span><?php</span><span><span>class</span><span>test</span>{</span><span>public</span><span>$name</span>=<span>'demon'</span>;

    <span>private</span><span>$age</span>=<span>'19'</span>;

    <span>public</span><span><span>function</span><span>__sleep</span><span>()</span>{</span><span>return</span> [<span>'name'</span>];
    }  
}

<span>$test</span> = <span>new</span> test();
<span>echo</span> serialize(<span>$test</span>);
<span>//输出结果：O:4:"test":1:{s:4:"name";s:5:"demon";}</span></code>

__wakeup()

使用serialize()序列化的時候，會偵測類別中是否有__wakeup()魔術方法，有的話會先呼叫__wakeup()，執行一些初始化運算

<code><span><?php</span><span><span>class</span><span>test</span>{</span><span>public</span><span>$name</span>=<span>'demon'</span>;

    <span>private</span><span>$age</span>=<span>'19'</span>;

    <span>public</span><span><span>function</span><span>say</span><span>()</span>{</span><span>echo</span><span>"反序列化"</span>;
    }

    <span>public</span><span><span>function</span><span>__wakeup</span><span>()</span>{</span><span>$this</span>->say();
    }   
}

<span>$test</span> = <span>new</span> test();
unserialize(serialize(<span>$test</span>));
<span>//输出结果：反序列化</span></span></code>

__toString()

__toString()用於一個類被當做字符串使用時的回應，只能返回一個字符串

<code><span><?php</span><span><span>class</span><span>test</span>{</span><span>public</span><span>$name</span>=<span>'demon'</span>;

    <span>private</span><span>$age</span>=<span>'19'</span>;

    <span>public</span><span><span>function</span><span>__toString</span><span>()</span>{</span><span>return</span><span>'test'</span>;
    } 
}

<span>$test</span> = <span>new</span> test();
<span>echo</span><span>$test</span>;
<span>//输出结果：test</span></code>

__debuginfo()

__debuginfo() 是php5.6增加的特性，var_dump ()一個類別時的回應，傳回一個包含物件屬性的陣列

<code><span><?php</span><span><span>class</span><span>test</span>{</span><span>public</span><span>$name</span>=<span>'demon'</span>;

    <span>private</span><span>$age</span>=<span>'19'</span>;

    <span>public</span><span><span>function</span><span>__debuginfo</span><span>()</span>{</span><span>return</span> [<span>'name'</span>];
    }

}

<span>$test</span> = <span>new</span> test();
var_dump(<span>$test</span>);
<span>//输出结果：object(test)#1 (1) { [0]=> string(4) "name" }</span></code>

').addClass('pre-numbering').hide(); $(this).addClass('has-numbering').parent().append($numbering); for (i = 1; i ').text(i)); }; $numbering.fadeIn(1700); }); });

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