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php面向对象中static静态属性与方法的内存位置分析_php技巧

May 16, 2016 pm 08:23 PM
php static Attributes method static object-oriented

本文实例分析了php面向对象中static静态属性与方法的内存位置。分享给大家供大家参考。具体如下:

static静态属性的内存位置——>类,而不是对象。下面做测试来证明一下

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<&#63;php

header("content-type:text/html;charset=utf-8");

class Human{

 static public $name = "小妹";

 public $height;

 public function tell(){

 }

}

echo Human:$name;

//不依赖于对象,就能直接访问。因为静态属性的内存位置是在类里,而不是对象。

$p1 = new Human();

$p2 = new Human();

print_r($p1);

echo $p1::$name = "夫人";

//在$p1对象上改变静态属性的值,那$p2对象也会相应的改变。

echo $p2::$name;

&#63;>

Copy after login

输出结果可以看出:

1、echo Human:$name :类声明完毕,就存在static属性,并不依赖于对象。因此,静态属性只有一个(意思是在内存里,存放的位置并不是在对象里;如果在对象里,那实例化一个对象,就相应的有该静态的位置,如height属性);

2、print_r($p1):打印结果只有height属性,而没有name;

3、静态属性的值变化后,所有对象的该属性值都会受到影响。

对于方法,无论是静态的、还是普通的,都是存在于类内存空间中。证明也很简单,new一个对象,print_r(对象)即可。

希望本文所述对大家的php程序设计有所帮助。

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