PHP中new static()与new self()的比较

  后天在coding的时候,发现了 new static(),觉得实例化的地点不是应当是
new self()吗?查询了一晃才通晓相互的区分:

  1)在有子类集成的时候,两者的展现不等同

  2)php 5.2及以下的版本不协助 new static()的语法

 

具体解释如下:

self - 就是这个类,是代码段里面的这个类。

static - PHP 5.3加进来的只得是当前这个类,有点像$this的意思,从堆内存中提取出来,访问的是当前实例化的那个类,那么 static 代表的就是那个类。

还是看看老外的专业解释吧:

self refers to the same class whose method the new operation takes place in.

static in PHP 5.3's late static bindings refers to whatever class in the hierarchy which you call the method on.

In the following example, B inherits both methods from A. self is bound to A because it's defined in A's implementation of the first method, whereas static is bound to the called class (also see  get_called_class() ).

 

上代码:

 

 1 class Person {
 2   public static function get_self() {
 3     return new self();
 4   }
 5  
 6   public static function get_static() {
 7     return new static();
 8   }
 9 }
10  
11 class WangBaoqiang extends Person{}
12  
13 echo get_class(WangBaoqiang::get_self()); // Person
14 echo get_class(WangBaoqiang::get_static()); // WangBaoqiang
15 echo get_class(Person::get_static()); // Person

 

可是若是想让 子类使用 get_class时,重返的也是
当前子类的名号(’wangbaoqiang’),该如何是好呢。

<?php
class Person {
  public function create1() {
    $class = get_class($this);
    return new $class();
  }
  public function create2() {
    return new static();
  }
}

class WangBaoqiang extends Person {

}

$wangBaoQiang = new WangBaoqiang();
var_dump(get_class($wangBaoQiang->create1()), get_class($wangBaoQiang->create2()));

/*
The result 
string(1) "WangBaoqiang"
string(1) "WangBaoqiang"
*/

PHP, 

 

迎接大家,批评指正,谢谢

 

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