PHP 语法

匿名函数

匿名函数也叫做闭包函数 即不指定名称的函数 常用作回调函数参数的值

匿名函数演示一

$values = array(‘first‘,‘second‘,‘third‘);array_map(function($para){ ???echo $para; ???echo "<br>";}, $values);## 输出 ## first## second## third 

匿名函数演示二

$myPrint = function($msg){ ???echo $msg; ???echo "<br>";};$myPrint("hello world");## 输出 hello world

匿名函数演示三 使用外部定义变量

$name = "Json";$myPrint = function($msg) use($name){ ???echo $msg." ".$name; ???echo "<br>";};$myPrint("hello");## 输出 hello Json

后期静态绑定

在类的继承过程中 使用的类不再是当前类 而是调用的类 使用关键字 static来实现 "static::function()" 不再被解析为定义当前方法所在的类 而是在实际运行时计算得到的

静态方法演示

class A { ???public static function call() { ???????echo __CLASS__; ???????echo "<hr>"; ???} ???public static function test() { ???????self::call(); ???????static::call(); ???}}class B extends A { ???public static function call() { ???????echo __CLASS__; ???????echo "<hr>"; ???}}B::test();## 输出## A## ----------## B

非静态方法演示

class A { ???public function call() { ???????echo __CLASS__; ???????echo "<hr>"; ???} ???public function test() { ???????self::call(); ???????static::call(); ???}}class B extends A { ???public function call() { ???????echo __CLASS__; ???????echo "<hr>"; ???}}B::test();

static会根据运行时调用的类来决定实例化对象 而self是根据所在位置的类来决定实例化对象

反射

主要是用来动态的获取系统中的类 实例对象 方法等信息

class People{ ???private $name ??= ‘Json‘; ???private $age ???= 20; ???//Constructor ???public function __construct() ???{ ???????//Constructor ???} ???//print variable one ???public function getName() ???{ ???????echo $this->name."\n"; ???} ???//print variable two ???public function getAge() ???{ ???????echo $this->age."\n"; ???}}$reflector = new ReflectionClass(‘People‘);print_r($reflector->getProperties());## 输出 Array ( [0] => ReflectionProperty Object ( [name] => name [class] => People ) [1] => ReflectionProperty Object ( [name] => age [class] => People ) )print_r($reflector->getMethods());##输出 Array ( [0] => ReflectionMethod Object ( [name] => __construct [class] => People ) [1] => ReflectionMethod Object ( [name] => getName [class] => People ) [2] => ReflectionMethod Object ( [name] => getAge [class] => People ) )

trait

由于PHP是单继承的语言 但是又想实现代码复用的功能 就可以使用trait。trait不能像类一样进行实例化 而是通过关键字use添加到其它类的内部

trait sayHello { ???public function sayHello() { ???????echo ‘Hello ‘; ???}}trait sayWorld { ???public function sayWorld() { ???????echo ‘World‘; ???}}class myHelloWorld { ???use sayHello, sayWorld; ???public function say() { ???????echo ‘!!!‘; ???}}$say = new MyHelloWorld();$say->sayHello();$say->sayWorld();$say->say();## 输出 Hello World!!!