ReflectionClass::getConstructor

(PHP 5, PHP 7)

ReflectionClass::getConstructor — 获取类的构造函数

说明

public ReflectionMethod ReflectionClass::getConstructor ( void )

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

User Contributed Notes

jochem at drecomm dot nl 13-May-2011 05:13
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
Rob McVey 16-Jul-2010 04:47
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