(PHP 8)
ReflectionProperty::getDefaultValue — Returns the default value declared for a property
Gets the implicit or explicitly declared default value for a property.
此函数没有参数。
   The default value if the property has any default value (including null).
   If there is no default value, then null is returned. It is not possible to differentiate
   between a null default value and an unitialized typed property.
   Use ReflectionProperty::hasDefaultValue() to detect the difference.
  
示例 #1 ReflectionProperty::getDefaultValue() example
<?php
class Foo {
    public $bar = 1;
    public ?int $baz;
    public int $boing = 0;
}
$ro = new ReflectionClass(Foo::class);
var_dump($ro->getProperty('bar')->getDefaultValue());
var_dump($ro->getProperty('baz')->getDefaultValue());
var_dump($ro->getProperty('boing')->getDefaultValue());
?>
以上例程会输出:
int(1) NULL int(0)