Detailed explanation of the usage of two reflection classes, ReflectionClass and ReflectionMethod, in PHP

This article mainly introduces the use cases of PHP's reflection class ReflectionClass and ReflectionMethod. This article also introduces what reflection is, what reflection can do, and gives a specific example. It is a good introductory article. You need Friends can refer to

PHP5 has 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 dynamically obtained information and the function of dynamically calling methods of objects are called reflection APIs. 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 are: Automatically load plug-ins, automatically generate 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 ReflectionMethod class, for example:

The code is as follows:

<?php
class 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 The following information of the Person class can be obtained:

1. Constants
2. Property Names
3. Method Names static
4. Properties Static Properties
5 .Namespace Namespace
6.Whether the Person class is final or abstract
7.Whether the Person class has a certain method

Next to reflect it, just put the class name " Person" can be passed to ReflectionClass:

The code is as follows:

$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) Get the properties (Properties):

The code is as follows:

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

By default, ReflectionClass will obtain all properties, including private and protected ones. If you only want to get the private attribute, you need to pass an additional parameter:

The code is as follows:

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

Available parameter list:

The code is as follows:

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

The property name can be obtained through $property->getName().

2) Get comments:

You can get the comments written to the property through getDocComment.

The code is as follows:

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) Get the method of the class

The code is as follows:

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) Execution class method:

The code is as follows:

$instance->getName(); // 执行Person 里的方法getName
// 或者：
$method = $class->getmethod('getName'); // 获取Person 类中的get
Name方法
$method->invoke($instance);    // 执行getName 方法
// 或者：
$method = $class->getmethod('setName'); // 获取Person 类中的setName方法
$method->invokeArgs($instance, array('snsgou.com'));

2. Pass ReflectionMethod, we can get information about a method of the Person class:

1. Whether it is of "public", "protected", "private", or "static" type
2. Parameters of the method List
3. Number of parameters of the method
4. Reverse calling class method

The code is as follows:

// 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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