在PHP中如何形成static与new static的静态绑定
发布时间：2022-06-24 13:13:52 所属栏目：PHP教程 来源：互联网
导读：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 $this-
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PHP中static::与new static()之后期静态绑定 一、parent、self、$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、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。 三、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。 （编辑：应用网_丽江站长网） 【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容! |
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