php构造函数与析构函数,php构造函数
php构造函数是对象创建完成后,第一个自动调用的方法,析构函数是当对象被释放之前最后一个自动调用的方法。本文章向码农介绍php构造函数与析构函数。
php构造函数
1.是对象创建完成后,“第一个”“自动调用”的方法
2.构造方法的定义,方法名是一个固定的,
在php4中:和类名相同的方法就是构造方法
在php5中:构造方法选择使用 魔术方法__construct() 所有类中声明构造方法都使用这个名称
优点:在改变类名时,构造方法不用改变
魔术方法: 在类中写出了某个魔术方法,这个方法对应的功能就会添加上
方法名称都是固定的(都是系统提供好的),没有自己定义的
每一个魔术方法,都是在不同时刻为了完成某一功能自动调用的方法
不同的魔术方法有不同的调用时机
都是以 __ 开头的方法
__construct(); __destruct(); __set();......
作用:为成员属性初始化;
php析构函数
1.当对象被释放之前最后一个“自动”调用的方法
使用垃圾回收器(java php),而c++手动 的释放
作用:关闭一些资源,作一些清理的工作
__destruct();
php构造函数与析构函数实例
<span>class</span><span> Person{ </span><span>var</span> <span>$name</span><span>; </span><span>var</span> <span>$age</span><span>; </span><span>var</span> <span>$sex</span><span>; </span><span>//</span><span>php4中的构造方法 </span><span> /*</span><span>function Person() { //每声明一个对象都会调用 echo "1111111111111111"; }</span><span>*/</span> <span>//</span><span>php5中的构造方法 </span> <span>function</span> __construct(<span>$name</span>,<span>$age</span>,<span>$sex</span><span>){ </span><span>$this</span>->name=<span>$name</span><span>; </span><span>$this</span>->age=<span>$age</span><span>; </span><span>$this</span>->sex=<span>$sex</span><span>; } </span><span>function</span><span> say(){ </span><span>//</span><span>$this->name;//对象中成员的访问使用$this </span> <span>echo</span> "我的名字:{<span>$this</span>->name},我的年龄:{<span>$this</span>->age}<br>"<span> } </span><span>function</span><span> run(){ } </span><span>function</span><span> eat(){ } </span><span>//</span><span>析构方法 </span> <span>function</span><span> __destruct(){ } } </span><span>$p1</span>=<span>new</span> Person("zhangsan",25,"男"<span>); </span><span>$p2</span>=<span>new</span><span> Person; </span><span>$p3</span>=<span>new</span> Person;
原文地址:http://www.manongjc.com/article/730.html
相关阅读:
php析构函数的简单使用说明
php初始化对象构造函数和析构函数的简单实例
php构造函数,析构函数和this关键字详细介绍
php构造函数和析构函数解析

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