php中static和self的区别

在阅读一些框架的源码时发现了new static()，和new self()，甚是不解，后来查阅资料，才知道static采用了延迟绑定，能准确知道是父类还是子类的调用。这就是说static是个聪明的小孩，家里的亲戚的辈分他都能准确的叫出；而不是像他的兄弟self，只知道自己的亲爹妈。

例子如下：

<?php

class Father{
    protected  static $name = "father";
    public static function whoami_self(){
        echo self::$name."\n";
    }
    
    public static function whoami_static(){
        echo static::$name."\n";
    }
    
    public static function getInstance_self(){
        return new self();
    }
    
    public static function getInstance_static(){
        return new static();
    }
}

class FatherBrother extends Father{
    protected  static $name = "uncle";
}

FatherBrother::whoami_self(); //father
FatherBrother::whoami_static(); //uncle
var_dump(FatherBrother::getInstance_self()); //father
var_dump(var_dump(FatherBrother::getInstance_static())); //uncle