公共，私有和受保护之间有什么区别?
何时以及为什么应该在类中使用 public、private 和 protected 函数和变量?它们有什么区别?
When and why should I use public, private, and protected functions and variables inside a class? What is the difference between them?
例子:
// Public
public $variable;
public function doSomething() {
// ...
}
// Private
private $variable;
private function doSomething() {
// ...
}
// Protected
protected $variable;
protected function doSomething() {
// ...
}
推荐答案
你用:
public范围以使该属性/方法可在任何地方、对象的其他类和实例中使用.
publicscope to make that property/method available from anywhere, other classes and instances of the object.
private 范围，当您希望您的属性/方法仅在其自己的类中可见时.
private scope when you want your property/method to be visible in its own class only.
protected 范围，当您想让您的属性/方法在所有扩展当前类(包括父类)的类中可见时.
protected scope when you want to make your property/method visible in all classes that extend current class including the parent class.
如果不使用任何可见性修饰符，则属性/方法将是公共的.
If you don't use any visibility modifier, the property / method will be public.
更多:(获取全面信息)
- PHP 手册 - 可见性