解析PHP5析构函数的具体使用方法_PHP教程

在升级版的在PHP5中，则使用__construct()来命名构造函数，而不再是与类同名，这样做的好处是可以使构造函数独立于类名，当类名改变时，不需要在相应的去修改构造函数的名称。

与构造函数相反，在PHP5中，可以定义一个名为__destruct()的函数，称之为PHP5析构函数，PHP将在对象在内存中被销毁前调用析构函数，使对象在彻底消失之前完成一些工作。对象在销毁一般可以通过赋值为null实现。

<ol class="dp-xml">
<li class="alt"><span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">php</span></font></strong><span> </span></span></li>
<li class=""><span>/*  </span></li>
<li class="alt"><span> * Created on 2009-11-18  </span></li>
<li class=""><span> *  </span></li>
<li class="alt"><span> * To change the template for this generated file go to  </span></li>
<li class=""><span> * Window - Preferences - PHPeclipse - PHP - Code Templates  </span></li>
<li class="alt"><span> */  </span></li>
<li class=""><span> class student{  </span></li>
<li class="alt"><span>  //属性  </span></li>
<li class=""><span>  private $no;  </span></li>
<li class="alt"><span>  private $name;  </span></li>
<li class=""><span>  private $gender;  </span></li>
<li class="alt"><span>  private $age;  </span></li>
<li class=""><span>    </span></li>
<li class="alt">
<span>  private static $</span><span class="attribute"><font color="#ff0000">count</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">0</font></span><span>;  </span>
</li>
<li class=""><span>  function __construct($pname)  </span></li>
<li class="alt"><span>  {  </span></li>
<li class="">
<span>   $this-</span><span class="tag"><strong><font color="#006699">></font></strong></span><span class="attribute"><font color="#ff0000">name</font></span><span> = $pname;  </span>
</li>
<li class="alt"><span>   self::$count++;  </span></li>
<li class=""><span>  }  </span></li>
<li class="alt"><span>    </span></li>
<li class=""><span>  function __destruct()  </span></li>
<li class="alt"><span>  {  </span></li>
<li class=""><span>   self::$count--;  </span></li>
<li class="alt"><span>  }  </span></li>
<li class=""><span>    </span></li>
<li class="alt"><span>  static function get_count()  </span></li>
<li class=""><span>  {  </span></li>
<li class="alt"><span>   return self::$count;  </span></li>
<li class=""><span>  }  </span></li>
<li class="alt"><span> }  </span></li>
<li class=""><span>   </span></li>
<li class="alt">
<span> $</span><span class="attribute"><font color="#ff0000">s1</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">new</font></span><span> student("Tom");  </span>
</li>
<li class=""><span> print(student::get_count());  </span></li>
<li class="alt"><span>   </span></li>
<li class="">
<span> $</span><span class="attribute"><font color="#ff0000">s2</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">new</font></span><span> student("jerry");  </span>
</li>
<li class="alt"><span> print(student::get_count());  </span></li>
<li class=""><span>   </span></li>
<li class="alt">
<span> $</span><span class="attribute"><font color="#ff0000">s1</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">NULL</font></span><span>;  </span>
</li>
<li class=""><span> print(student::get_count());  </span></li>
<li class="alt"><span>   </span></li>
<li class="">
<span> $</span><span class="attribute"><font color="#ff0000">s2</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">NULL</font></span><span>;  </span>
</li>
<li class="alt"><span> print(student::get_count());  </span></li>
<li class="">
<span></span><span class="tag"><strong><font color="#006699">?></font></strong></span><span> </span>
</li>
</ol>

上面这段代码就是PHP5析构函数的具体使用方法，希望对大家有所帮助。

http://www.bkjia.com/PHPjc/446387.htmlwww.bkjia.comtruehttp://www.bkjia.com/PHPjc/446387.htmlTechArticle在升级版的 在PHP5中，则使用__construct()来命名构造函数，而不再是与类同名，这样做的好处是可以使构造函数独立于类名，当类名改变时，...