What does encapsulation mean in php

In PHP, encapsulation is to separate the use and implementation of a class, leaving only a limited interface (method) to contact the outside; for developers who use this class, as long as they know how to use this class However, you don't have to worry about how this class is implemented.

The operating environment of this tutorial: windows7 system, PHP7.1 version, DELL G3 computer

PHP is an object-oriented programming language .

Object-oriented is a programming idea that conforms to human thinking habits. There are various things of different forms in real life, and there are various connections between these things. Using objects in programs to map things in reality and using object relationships to describe the connections between things is object-oriented.

Characteristics of object-oriented programming

Object-oriented programming has three major characteristics: encapsulation, inheritance, and polymorphism. They cater to the emphasis on code reusability, flexibility and flexibility in programming. The need for scalability has established the position of object-oriented programming in programming.

1) Encapsulation

Encapsulation is to separate the use and implementation of a class, leaving only limited interfaces (methods) to communicate with the outside. For developers who use this class, they only need to know how to use this class, and do not need to care about how this class is implemented. Doing so allows developers to better focus on other things, while also avoiding the inconvenience caused by interdependencies between programs.

For example, when using a computer, we do not need to disassemble the computer to understand the specific use of each component. We only need to press the power button to start the computer, which reflects the benefits of packaging.

2) Inheritance

Inheritance means that a derived class (subclass) automatically inherits the properties and methods in one or more base classes (parent classes), and can override or add new properties. or method. Inheritance simplifies the creation of objects and classes and increases code reusability.

For example, class A has been defined, and class B is going to be defined next. Class B has many attributes and methods that are the same as class A. Then class B can be used to inherit class A, so that there is no need to Class B defines the existing properties and methods in class A, which can greatly improve the development efficiency of the program.

Inheritance is divided into single inheritance and multiple inheritance. PHP currently only supports single inheritance, which means that a subclass has only one parent class.

3) Polymorphism

The state of an object is changeable. An object can have different states compared to another object of the same class. Although they have the same properties and methods, they can have different states. In addition, a class can derive several subclasses. While retaining some properties and methods of the parent object, these subclasses can also define some new methods and properties, or even completely rewrite some existing properties of the parent class. Methods. Polymorphism enhances software flexibility and reusability.

Encapsulation in php

Encapsulation is one of the object-oriented features of PHP, which encapsulates multiple reusable functions into a class. Directly instantiate a method of this class when using it to obtain the required data

If it is a private method and attribute value, it cannot be accessed from the outside, which has a certain protective effect.

Object-oriented encapsulation example

class A{
         public $name = '老王';
        // protected $name = '老王';
        //private $name = '老王';

        //自己访问
        public function saya(){
            return $this->name;
        }
    }
    //实例化对象
    $b = new A;

    //public：外部、家族、自己都可以访问
    //protected:家族和自己都可以访问，外部无法访问
    //private:自己可以访问，外部和家族都无法访问
    echo &#39;外部访问：&#39;.$b->name.&#39;<br>&#39;; //如果是私有的，访问不了
    echo &#39;家族访问：&#39;.$b->sayb().&#39;<br>&#39;;
    echo &#39;自己访问：&#39;.$b->saya().&#39;<br>&#39;;

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