PHP中static::与new static()静态绑定如何实现？

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PHP中`static::`与`new static()`之后的静态绑定：一、`parent`、`self`、`$this`、`__CLASS__`、`class A { ... } class B extends A { parent::（public|protected）（静态方法|静态变量）=parent::（静态方法|静态变量）； self::（public|protected）（静态方法|静态变量）=self::（静态方法|静态变量）； }

PHP中static::与new static()之后期静态绑定

一、parent、self、$this、__CLASS__

class A {} class B extends A{ parent::(public|protected)(静态方法|静态变量) ===> parent永远是A self::(public|protected)(静态方法|静态变量) ===> self永远是B $this->(public|protected)(非静态方法|非静态变量) ===> $this永远是B的是实例化对象 __CLASS__ ===> 永远是B } class C extends B{ parent::(public|protected)(静态方法|静态变量) ===> parent永远是B self::(public|protected)(静态方法|静态变量) ===> self永远是C $this->(public|protected)(非静态方法|非静态变量) ===> $this永远是C的是实例化对象 __CLASS__ ===> 永远是C }

二、static::

static关键字可以实现以下功能：

1 调用类的静态方法 有后期静态绑定效果；

2 调用类的静态属性 有后期静态绑定效果；

3 调用类的非静态方法 没有后期静态绑定效果；

4 注意：不可以调用非静态属性；

class A { private static function foo() { echo "A success!\n"; } public function test() { $this->foo(); } } class B extends A { } class C extends A { private static function foo() { echo "C success!\n"; } } $b = new B(); $b->test();//A success! $c = new C(); $c->test();//A success!

class A { private static function foo() { echo "A success!\n"; } public function test() { static::foo(); } } class B extends A { } class C extends A { private static function foo() { echo "C success!\n"; } } $b = new B(); $b->test();//A success! $c = new C(); $c->test();//A无法调用C里的私有foo方法 //将C的foo改成非private(public|protected)就可以解决 class A { private static function foo() { echo "A success!\n"; } public function test() { static::foo(); } } class B extends A { } class C extends A { public static function foo() { echo "C success!\n"; } } $b = new B(); $b->test();//A success! $c = new C(); $c->test();//C success!

class A { public static function foo() { static::who(); } public static function who() { echo __CLASS__."\n"; } } class B extends A { public static function test() { A::foo(); parent::foo(); self::foo(); } public static function who() { echo __CLASS__."\n"; } } class C extends B { public static function who() { echo __CLASS__."\n"; } } C::test(); A =>A::foo()的结果 C =>parent::foo()能走到A的foo,里面static::who找C::who C =>self::foo()能走到B的foo,B继承A,走到A的foo,里面static::who找C::who class A { protected static function foo() { static::who(); } protected static function who() { echo __CLASS__."\n"; } } class B extends A { public static function test() { A::foo(); parent::foo(); self::foo(); } protected static function who() { echo __CLASS__."\n"; } } class C extends B { protected static function who() { echo __CLASS__."\n"; } } C::test(); //A C C,解释同上 class A { public static function foo() { static::who(); } private static function who() { echo __CLASS__."\n"; } } class B extends A { public static function test() { A::foo(); parent::foo(); // self::foo(); } private static function who() { echo __CLASS__."\n"; } } class C extends B { private static function who() { echo __CLASS__."\n"; } } C::test(); //A =>A::foo()的结果 //报错 A不可C的私有方法who => parent::foo()能走到A的foo,里面static::who找C::who,C的who只能在C里调用，不能在A里调用 //报错 A不可C的私有方法who => self::foo()能走到B的foo,B继承A,走到A的foo,里面static::who找C::who,C的who只能在C里调用，不能在A里调用

三、new static()

//new self()与new static()的区别，官网例子如下： class A { public static function get_self() { return new self(); } public static function get_static() { return new static(); } } class B extends A {} echo get_class(B::get_self()); // A echo get_class(B::get_static()); // B echo get_class(A::get_static()); // A

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