Reflection classes in PHP

This article introduces the reflection classes in PHP, which has certain reference value. Now I share it with you. Friends in need can refer to

Usage examples of PHP's reflection classes ReflectionClass and ReflectionMethod.

# Author: @keenleung

This article Original by the author, please indicate the source when reprinting: https://www.cnblogs.com/KeenLeung/p/6041280.html

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##Table of Contents

PHP5 Features a complete reflection API, adding the ability to reverse engineer classes, interfaces, functions, methods and extensions.

What is reflection?

It refers to extending the analysis of PHP programs in the running state of PHP and exporting or extracting detailed information about classes, methods, properties, parameters, etc., including comments. This function of dynamically obtaining information and dynamically calling methods of objects is called reflection API. Reflection is an API for manipulating meta-models in the object-oriented paradigm. It is very powerful and can help us build complex and scalable applications.

Its uses include: automatically loading plug-ins, automatically generating documents, and can even be used to expand the PHP language.

PHP reflection api consists of several classes that help us access the metadata of the program or interact with related annotations. With the help of reflection, we can obtain the methods implemented by the class, create an instance of the class (different from creating with new), call a method (also different from the regular call), pass parameters, and dynamically call the static methods of the class.

Reflection api is PHP's built-in OOP technology extension, including some classes, exceptions and interfaces. Used together, they can be used to help us analyze other classes, interfaces, methods, properties, methods and extensions. These OOP extensions are called reflection.

We usually use the ReflectionClass class and the ReflectionMethod class. For example:

The code is as follows:

##

<?phpclass  Person {

 /**
  * For the sake of demonstration, we"re setting this private  */
 private $_allowDynamicAttributes = false; /**
  * type=primary_autoincrement  */
 protected $id = 0; /**
  * type=varchar length=255 null  */
 protected $name; /**
  * type=text null  */
 protected $biography; public function getId() {  return $this->id;
 } public function setId($v) {  $this->id = $v;
 } public function getName() {  return $this->name;
 } public function setName($v) {  $this->name = $v;
 } public function getBiography() {  return $this->biography;
 } public function setBiography($v) {  $this->biography = $v;
 }
}

1. Through ReflectionClass, we can get the following information of the Person class:

1. Constants2. Property Names

3. Method Names static

4. Static Properties
5. Namespace Namespace
6. Whether the Person class is final or abstract
7. Whether the Person class has a certain method

Next reflect it, as long as Just pass the class name "Person" to ReflectionClass:

代码如下:

$class = new ReflectionClass('Person'); // 建立 Person这个类的反射类
$instance  = $class->newInstanceArgs($args); // 相当于实例化Person 类

 

1）获取属性(Properties)：

 代码如下:

$properties = $class->getProperties();foreach ($properties as $property) { echo $property->getName() . "\n";
}// 输出:
// _allowDynamicAttributes
// id
// name
// biography

 

默认情况下，ReflectionClass会获取到所有的属性，private 和 protected的也可以。如果只想获取到private属性，就要额外传个参数：

代码如下:

$private_properties = $class->getProperties(ReflectionProperty::IS_PRIVATE);

 

可用参数列表：

代码如下:

ReflectionProperty::IS_STATIC
ReflectionProperty::IS_PUBLIC
ReflectionProperty::IS_PROTECTED
ReflectionProperty::IS_PRIVATE

 通过$property->getName()可以得到属性名。

 

2）获取注释：

通过getDocComment可以得到写给property的注释。

代码如下:

foreach ($properties as $property) {
if ($property->isProtected()) {
$docblock = $property->getDocComment();
preg_match('/ type\=([a-z_]*) /', $property->getDocComment(), $matches);  echo $matches[1] . "\n";
 }
}// Output:
// primary_autoincrement
// varchar
// text

 

3）获取类的方法

 代码如下:

getMethods()       来获取到类的所有methods。
hasMethod(string)  是否存在某个方法
getMethod(string)  获取方法

 

 4）执行类的方法：

代码如下:

->getName();  = ->getmethod('getName'); ->invoke();     = ->getmethod('setName'); ->invokeArgs(, ('snsgou.com'

 

二、通过ReflectionMethod，我们可以得到Person类的某个方法的信息：

1.是否“public”、“protected”、“private” 、“static”类型
2.方法的参数列表
3.方法的参数个数
4.反调用类的方法

代码如下:

// 执行detail方法
$method = new ReflectionMethod('Person', 'test');

if ($method->isPublic() && !$method->isStatic()) {
echo 'Action is right';
}echo $method->getNumberOfParameters(); // 参数个数
echo $method->getParameters(); // 参数对象数组

 

 

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