php中static::与new static()之后期静态绑定
一、parent、self、$this、__class__
class a {}class b extends a{parent::(public|protected)(静态方法|静态变量) ===> parent永远是aself::(public|protected)(静态方法|静态变量) ===> self永远是b$this->(public|protected)(非静态方法|非静态变量) ===> $this永远是b的是实例化对象__class__ ===> 永远是b} class c extends b{parent::(public|protected)(静态方法|静态变量) ===> parent永远是bself::(public|protected)(静态方法|静态变量) ===> self永远是c$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::whoc =>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()); // aecho get_class(b::get_static()); // becho get_class(a::get_static()); // a
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以上就是php中如何形成static::与new static()的静态绑定的详细内容。