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ReflectionClass::getConstructor

(PHP 5, PHP 7)

ReflectionClass::getConstructor获取类的构造函数

说明

public ReflectionClass::getConstructor ( void ) : ReflectionMethod

获取已反射的类的构造函数。

参数

此函数没有参数。

返回值

一个 ReflectionMethod 对象,反射了类的构造函数,或者当类不存在构造函数时返回 NULL

范例

Example #1 ReflectionClass::getConstructor() 的基本用法

<?php
$class 
= new ReflectionClass('ReflectionClass');
$constructor $class->getConstructor();
var_dump($constructor);
?>

以上例程会输出:

object(ReflectionMethod)#2 (2) {
  ["name"]=>
  string(11) "__construct"
  ["class"]=>
  string(15) "ReflectionClass"
}

参见

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User Contributed Notes 3 notes

up
3
Rob McVey
9 years ago
Just posting some example code for anyone wanting to mess around with this stuff:

<?php

class Say
{
    private
$what_to_say;
    public function
__construct($no_default, $word = "Hello World", $options = array('a', 'b'))
    {
       
$this->what_to_say = $word;
    }
   
    public function
speak()
    {
        echo
$this->what_to_say;
    }
}

$class = new ReflectionClass('Say');

$constructor = $class->getConstructor();

echo
$constructor;

/*     OUTPUTS:

Method [ <user, ctor> public method __construct ] {
  @@ /reflect.php 6 - 9

  - Parameters [3] {
    Parameter #0 [ <required> $no_default ]
    Parameter #1 [ <optional> $word = 'Hello World' ]
    Parameter #2 [ <optional> $options = Array ]
  }
}

*/

$parameters = $constructor->getParameters();

var_export($parameters);

/*    OUTPUT:

array (
  0 =>
  ReflectionParameter::__set_state(array(
     'name' => 'no_default',
  )),
  1 =>
  ReflectionParameter::__set_state(array(
     'name' => 'word',
  )),
  2 =>
  ReflectionParameter::__set_state(array(
     'name' => 'options',
  )),
)

*/

$nl = "\n";
echo
"$nl\tParameters$nl";
foreach(
$parameters as $param)
{
    echo
"****** $" . $param->name . " ******$nl";
    echo
"Nullable:\t\t" . $param->allowsNull() . $nl
        
."Default Value:\t\t";
    echo (
$param->isDefaultValueAvailable()) ? $param->getDefaultValue() : "None";
    echo
$nl ."Is Array:\t\t";
    echo (
$param->isArray()) ? "Yes" : "No";
    echo
$nl . "Optional:\t\t";
    echo (
$param->isOptional()) ? "Yes" : "No";
    echo
$nl;
}

/*    OUTPUT:

    Parameters
****** $no_default ******
Nullable:        1
Default Value:    None
Is Array:        No
Optional:        No
****** $word ******
Nullable:        1
Default Value:    Hello World
Is Array:        No
Optional:        Yes
****** $options ******
Nullable:        1
Default Value:    Array
Is Array:        No
Optional:        Yes

*/

?>

To clarify the possibly confusing behavior of ReflectionParemeter::isArray(), it will return true if the parameter has type hinting:

<?php
...
public function
__construct($no_default, $word = "Hello World", array $options = array('a', 'b'))
...
?>

Calling isArray() will now return true for the $options parameter
up
0
martin dot melka at gmail dot com
1 month ago
This method will return the parent's constructor, if the current class does not override it.

NULL will only be returned when the class has no constructor AND none of its parents have a constructor either.
up
0
jochem at drecomm dot nl
8 years ago
Old constructors also count as contructor:

<?php

class SomeClass {

    function
SomeClass($some_arg) {
    }

}

$refl = new ReflectionClass('SomeClass');

var_dump($refl->isInstantiable()); // bool(true)

echo $refl->getConstructor();

/* OUTPUT:
Method [ <user, ctor> public method SomeClass ] {
  @@ /var/www/vhosts/api.example.com/httpdocs/testRefl.php 5 - 6

  - Parameters [1] {
    Parameter #0 [ <required> $some_arg ]
  }
}
*/

?>

Some more behavior:

<?php

class SomeClass {

   function
funcA($arg1, $arg2) {

   }

}

$refl = new ReflectionClass('SomeClass');

var_dump($refl->isInstantiable()); // bool(true)

var_dump($refl->getConstructor()); // NULL

/* --------------- */

class AnotherClass {

   private function
__construct() {
   }

   function
funcB($arg1, $arg2) {

   }

}

$refl = new ReflectionClass('AnotherClass');

var_dump($refl->isInstantiable()); // bool(false)

echo $refl->getConstructor();
/*
Method [ <user, ctor> private method __construct ] {
  @@ /testRefl.php 22 - 23
}
*/

?>

Tested on PHP 5.2.4
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