php new static vs new self 区别

<?php
class A {
public static function get_self() {
return new self();
}

public static function () {
    return new static();
}

}

class B extends A {

}

echo get_class(B::get_self()); // A
echo ‘+++’;
echo get_class(B::get_static()); // B
echo ‘+++’;
echo get_class(A::get_static()); // A
/*
self refers to the same class in which the new keyword is actually written.

static, in PHP 5.3’s late static bindings, refers to whatever class in the hierarchy you called the method on.

In the following example, B inherits both methods from A. The self invocation 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()).

• in all:
• static equal get_called_class
• self equal the basis class
  */