PHP’s object-oriented technology includes the following aspects:
Classes and objects: PHP supports defining classes and creating objects. A class is the blueprint of an object, which defines its properties and methods. By instantiating a class, you create a concrete object.
Encapsulation: Encapsulation is one of the core concepts of object-oriented programming. PHP provides access modifiers (public, protected, private) to control the visibility of properties and methods of a class. Through encapsulation, internal implementation details can be hidden and only the interfaces that need to be accessed are exposed.
Inheritance: Inheritance allows one class to inherit properties and methods from another class. Subclasses can have the properties and methods of the parent class, and can add new properties and methods to the subclass, or override the methods of the parent class. PHP uses the extends keyword to implement inheritance relationships.
Polymorphism: Polymorphism allows using different types of objects to call the same method and get different results. Polymorphism in PHP can be achieved through method overriding and interface implementation.
Abstract class: An abstract class is a class that cannot be directly instantiated. It can contain abstract methods and ordinary methods. Abstract methods have no concrete implementation and need to be implemented in subclasses. Abstract classes can serve as base classes for other classes to define shared behaviors and properties.
Interface: An interface is a convention that defines the methods that a class should implement. A class can implement one or more interfaces and provide concrete implementations of the methods defined in the interfaces. Interfaces can be used to achieve polymorphism and code reuse.
Constructor and destructor: The constructor (__construct) is automatically called when creating an object and is used to initialize the state of the object. The destructor (__destruct) is automatically called when the object is destroyed to perform cleanup work.
These are some of the key concepts and techniques of object-oriented programming in PHP. By mastering and flexibly applying these technologies, you can improve the maintainability, scalability, and reusability of your code.