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Homephp教程php手册PHP5中的访问控制!public ,private,protected

PHP5中的访问控制!public ,private,protected

Jun 13, 2016 am 10:36 AM
oopphp5privateprotectedpublicvariabledefinitioncontrolofaccess

php5 oop中类的变量定义遵循一种访问控制,就是:

public 表示全局,类内部外部子类都可以访问;

private表示私有的,只有本类内部可以使用;

protected表示受保护的,只有本类或子类或父类中可以访问;

class BaseClass {
public $public = public;
private $private = private;
protected $protected = protected;

function __construct(){
 
}

function print_var(){
   print $this->public;echo
;
   print $this->private; echo
;
   print $this->protected; echo
;
}

}

class Subclass extends BaseClass {

// public $public = public2;
protected $protected =protected2;
function __construct(){
   echo $this->protected;//可以访问,因为类中定义为受保护的,所以在本类或子类中可以,子类中还可以重复付值
   echo
;
   echo $this->private;//error 因为是私有的只有在定义她的类baseclass中可以用
}
}

$obj1 = new BaseClass();
$obj1->print_var();
//echo $obj1->protected;//error 因为是受保护的,只有在本类内部或子类父类中可以调用
//echo $obj1->private;//error 同上私有的,只有在本类内调用
echo $obj1->public;
echo "


";
$obj2 = new Subclass();
echo
;
echo $obj2->public;echo
;
echo $obj2->protected;
//echo $obj2->private;//error
//echo $obj2->protected;
?>

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