# ReflectionProperty::__construct

(PHP 5, PHP 7, PHP 8)

ReflectionProperty::__construct — Construct a ReflectionProperty object

### 说明

public ReflectionProperty::__construct(object|string `$class`, string `$property`)

### 参数

`class`

  Either a string containing the name of the class to reflect, or an object.

`property`

  The name of the property being reflected.

### 错误／异常

Trying to get or set private or protected class property's values will result in an exception being thrown.

### 示例

示例 #1 ReflectionProperty::__construct() example

`<?php
class Str
{
public $length = 5;
}
// Create an instance of the ReflectionProperty class
$prop = new ReflectionProperty('Str', 'length');
// Print out basic information
printf(
"===> The%s%s%s%s property '%s' (which was %s)\n" .
" having the modifiers %s\n",
$prop->isPublic() ? ' public' : '',
$prop->isPrivate() ? ' private' : '',
$prop->isProtected() ? ' protected' : '',
$prop->isStatic() ? ' static' : '',
$prop->getName(),
$prop->isDefault() ? 'declared at compile-time' : 'created at run-time',
var_export(Reflection::getModifierNames($prop->getModifiers()), true)
);
// Create an instance of Str
$obj= new Str();
// Get current value
printf("---> Value is: ");
var_dump($prop->getValue($obj));
// Change value
$prop->setValue($obj, 10);
printf("---> Setting value to 10, new value is: ");
var_dump($prop->getValue($obj));
// Dump object
var_dump($obj);
?>`

以上示例的输出类似于：

    ===> The public property 'length' (which was declared at compile-time)
         having the modifiers array (
      0 => 'public',
    )
    ---> Value is: int(5)
    ---> Setting value to 10, new value is: int(10)
    object(Str)#2 (1) {
      ["length"]=>
      int(10)
    }

示例 #2 Getting value from private and protected properties using ReflectionProperty class

`<?php
class Foo
{
public $x = 1;
protected $y = 2;
private $z = 3;
}
$obj = new Foo;
$prop = new ReflectionProperty('Foo', 'y');
$prop->setAccessible(true);
var_dump($prop->getValue($obj)); // int(2)
$prop = new ReflectionProperty('Foo', 'z');
$prop->setAccessible(true);
var_dump($prop->getValue($obj)); // int(2)
?>`

以上示例的输出类似于：

    int(2)
    int(3)

### 参见

- ReflectionProperty::getName() - Gets property name
- Constructors

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