


PHP object-oriented access control public, private, protected detailed explanation_PHP tutorial
The article uses examples to illustrate detailed descriptions of PHP5 object-oriented access control Public, private, and protected. Friends in need can refer to it.
The object-oriented mechanism has been enhanced in PHP5, and common object-oriented access control mechanisms such as public, private, and protected have been added. To understand it literally:
Public undoubtedly means public, which means that both the class itself and its external subclasses can access this property or method;
Private means private in English. It can only be accessed within the class itself - the instantiated object handle cannot access the properties and methods, nor can subclasses;
Protected A protected property or method. This property or method can only be accessed internally by the class itself or its subclasses, and the instantiated object handle cannot be accessed.
Now let’s take an example to discuss this issue.
Suppose there is a gem museum administrator Xiao Li, who divides the gems in the warehouse into three categories, rubies, sapphires, and emeralds. And the attributes are divided. The ruby is marked as (public) which anyone in the country can visit, the sapphire is passed down by the administrator Xiao Li’s family (protected), and the emerald is what Xiao Li saw on the mountain (private).
Then we can think of it this way:
Rubys with the public label belong to the country - owned by all people. As long as they are legal citizens of the country, they can view and take photos.
Protected This is protected. Only members of Xiao Li's family (Xiao Li's children or grandchildren) can visit and take photos in a specific room. They are not allowed to look outside the room - so stingy!
Private This is private. Xiao Li doesn’t want other people to know, let alone take pictures, so it can only be seen by Xiao Li in Xiao Li’s room. Others, even Xiao Li’s children, cannot How to see
Example
The code is as follows | Copy code |
error_reporting(E_ALL);
class test{ public $public; private $private; protected $protected; static $instance; public function __construct(){ $this->public = 'public $this->private = 'private $this->protected = 'protected } static function tank(){ if (!isset(self::$instance[get_class()])) { $c = get_class(); self::$instance = new $c; }
return self::$instance; }
public function pub_function() { echo "you request public function echo $this->public; echo $this->private; //private, can be called internally echo $this->protected; //protected, can be called internally $this->pri_function(); //private method, can be called internally $this->pro_function(); //protected method, can be called internally } protected function pro_function(){ echo "you request protected function } private function pri_function(){ echo "you request private function } }
$test = test::tank(); echo $test->public; echo $test->private; //Fatal error: Cannot access private property test::$private echo $test->protected; //Fatal error: Cannot access protected property test::$protected $test->pub_function(); $test->pro_function(); //Fatal error: Call to protected method test::pro_function() from context $test->pri_function(); //Fatal error: Call to private method test::pri_function() from context
?>
public = 'public 从上面的例子中,我们可以看出,
class test{ public $public; private $private; protected $protected; static $instance;
public function __construct(){ $this->public = 'public $this->private = 'private $this->protected = 'protected } protected function tank(){ //私有方法不能继承,换成public,protected if (!isset(self::$instance[get_class()])) { $c = get_class(); self::$instance = new $c; } return self::$instance; }
public function pub_function() { echo "you request public function echo $this->public; } protected function pro_function(){ echo "you request protected function echo $this->protected; } private function pri_function(){ echo "you request private function echo $this->private; } }
class test1 extends test{
public function __construct(){ parent::tank(); parent::__construct(); } public function tank(){ echo $this->public; echo $this->private; //Notice: Undefined property: test1::$private echo $this->protected; $this->pub_function(); $this->pro_function(); $this->pri_function(); //Fatal error: Call to private method test::pri_function() from context 'test1' }
public function pro_extends_function(){ echo "you request extends_protected function } public function pri_extends_function(){ echo "you request extends_private function } }
error_reporting(E_ALL); $test = new test1(); $test -> tank(); //The subclass and the parent class have properties and methods with the same names. When instantiating the subclass, the properties and methods in the subclass will overwrite those of the parent class.
?> |

Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics

PHP 8.4 brings several new features, security improvements, and performance improvements with healthy amounts of feature deprecations and removals. This guide explains how to install PHP 8.4 or upgrade to PHP 8.4 on Ubuntu, Debian, or their derivati

If you are an experienced PHP developer, you might have the feeling that you’ve been there and done that already.You have developed a significant number of applications, debugged millions of lines of code, and tweaked a bunch of scripts to achieve op

Visual Studio Code, also known as VS Code, is a free source code editor — or integrated development environment (IDE) — available for all major operating systems. With a large collection of extensions for many programming languages, VS Code can be c

JWT is an open standard based on JSON, used to securely transmit information between parties, mainly for identity authentication and information exchange. 1. JWT consists of three parts: Header, Payload and Signature. 2. The working principle of JWT includes three steps: generating JWT, verifying JWT and parsing Payload. 3. When using JWT for authentication in PHP, JWT can be generated and verified, and user role and permission information can be included in advanced usage. 4. Common errors include signature verification failure, token expiration, and payload oversized. Debugging skills include using debugging tools and logging. 5. Performance optimization and best practices include using appropriate signature algorithms, setting validity periods reasonably,

This tutorial demonstrates how to efficiently process XML documents using PHP. XML (eXtensible Markup Language) is a versatile text-based markup language designed for both human readability and machine parsing. It's commonly used for data storage an

A string is a sequence of characters, including letters, numbers, and symbols. This tutorial will learn how to calculate the number of vowels in a given string in PHP using different methods. The vowels in English are a, e, i, o, u, and they can be uppercase or lowercase. What is a vowel? Vowels are alphabetic characters that represent a specific pronunciation. There are five vowels in English, including uppercase and lowercase: a, e, i, o, u Example 1 Input: String = "Tutorialspoint" Output: 6 explain The vowels in the string "Tutorialspoint" are u, o, i, a, o, i. There are 6 yuan in total

Static binding (static::) implements late static binding (LSB) in PHP, allowing calling classes to be referenced in static contexts rather than defining classes. 1) The parsing process is performed at runtime, 2) Look up the call class in the inheritance relationship, 3) It may bring performance overhead.

What are the magic methods of PHP? PHP's magic methods include: 1.\_\_construct, used to initialize objects; 2.\_\_destruct, used to clean up resources; 3.\_\_call, handle non-existent method calls; 4.\_\_get, implement dynamic attribute access; 5.\_\_set, implement dynamic attribute settings. These methods are automatically called in certain situations, improving code flexibility and efficiency.
