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Detailed explanation of the difference between php static methods and ordinary methods

怪我咯
怪我咯Original
2017-07-05 10:19:011652browse

The following editor will bring you a detailed discussion of the difference between phpstatic methods and ordinary methods. The editor thinks it is quite good, so I will share it with you now and give it as a reference for everyone. Let’s follow the editor and take a look.

is as follows:

<?php 
header(&#39;content-type:text/html;charset=utf-8&#39;); 
/* 
普通方法,存放类内,只有一份

静态方法,也是存放于类内,只有一份

区别在于:普通方法需要对象去调用,需要绑定$this 
即,普通方法,必须要有对象,然后让对象来调用 

而静态方法,不属于哪一个对象,因此不需要绑定$this 
即,不需要对象也可以调用 
*/

class Human{ 
  static public $head=1; 
  public function easyeat(){ 
    echo &#39;普通方法吃饭<br />&#39;; 
  } 
  static public function eat(){ 
    echo &#39;静态方法吃饭<br />&#39;; 
  } 
  public function intro(){ 
    echo $this->name; 
  } 
} 
Error_reporting(E_ALL|E_STRICT); 
//此时没有对象!方法可以执行 
Human::eat(); 
/* 
以下方法easyeat是一个非静态方法,就由对象来调用,但,用类来调用此方法来也可以执行,而严格状态下,此方法会执行,同时报错, 
Strict Standards: Non-static method Human::easyeat() should not be called statically in D:\application\PHPnow-1.5.6\htdocs\yan18\types\staticfun.php on line 32

*/ 
Human::easyeat(); 
/* 
接上,从逻辑来理解,如果用类名静态调用非静态(普通)方法 
比如:intro() 
那么,这个$this是指哪个对象呢?? 
因此会报错,因为找不到对象! 
Fatal error: Using $this when not in object context in D:\application\PHPnow-1.5.6\htdocs\yan18\types\staticfun.php on line 23 
*/ 
Human::intro();

/* 
如上分析,其实,非静态方法,是不能由类名静态调用的,但目前,php中的面向对象检测不够严格,只要静态方法中没有$this关键字,就会转化成静态方法来处理! 
*/ 
$li=new Human(); 
$li->eat();

/* 
总结: 
类》访问->静态方法(类的方法)->可以 
类》访问->普通方法(对象的方法)->不可以(虽然方法里不用$this关键字时,可以!但不支持这种写法)

对象》访问》静态方法(类的方法)->可以 
对象》访问》普通方法(对象的方法)->可以

*/ 
?>

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