Table of Contents
What is DI/Dependency Injection
Home Backend Development PHP Tutorial An article to talk about DI dependency injection in php

An article to talk about DI dependency injection in php

Aug 25, 2022 am 10:50 AM
php

What is DI dependency injection? The following article will give you an in-depth understanding of DI dependency injection in php. I hope it will be helpful to you!

An article to talk about DI dependency injection in php

What is DI/Dependency Injection

  • Dependency Injection DI In fact, it essentially means Dependence on the class is completed through the constructorAutomatic injection
  • In layman's terms, it means that you are currently operating a class, but some methods or functions of this class cannot be achieved by relying on this class alone. It can be completed only with the help of another class
  • The most direct sign is when the parameter data is passed as an object. Strictly speaking, you
  • want to operate one class in another class. There is an interdependence relationship between the two classes. The method of passing parameters is called injection

The reason why dependency injection appears

    When dependency injection is not used,
  • php When you need to use another class in one class , often the following operations are performed
  • For example, if I need to use the
  • adapter class in the container class, I need to instantiate it before use
  • If a large number of external classes need to be used, this will cause
  • the degree of coupling to be too high, which can easily lead to later maintenance difficulties
  • In lay terms, That is,
  • container cannot work without external classes. This is called too high coupling
<?php
class container
{
    private $adapter;

    public function __construct()
    {
        $this->adapter = new adapter();
    }
}
Copy after login

Simple dependency injection

    The coupling degree of the above code is too high, which leads to the emergence of
  • Dependency Injection, mainly for decoupling
  • For the following cases, we only You need to pass in the class object that needs to be operated
  • Dependency injection The parameters of the operation are objects, not ordinary parameters. Do you have a better understanding?
  • But such a simple dependency injection will cause if you depend on a lot of classes, it will take a long time when you pass parameters, which will easily
  • confuse
<?php
class container
{
    private $adapter;

    public function __construct(adapter $adapter)
    {
        $this->adapter = $adapter;
    }
}
Copy after login

High-level dependency injection

    In order to solve the above problem of
  • parameter confusion, at this time, dependency injection has been optimizedThrough the magic method,
    __get Set the object
  • At this time, we can solve the problem of too many dependencies and confusing parameters
<?php
class container
{
    public $instance = [];

    public function __set($name, $value)
    {
        $this->instance[$name] = $value;
    }
}

$container = new container();

$container->adapter = new adapter();
$container->autofelix = new autofelix();
Copy after login

Dependency injection application

    We first define a
  • container class, which is mainly used to inject the class you want to operate
  • into the container. At this time, you only need to pass the
  • object of the container
<?php
class container
{
    public $instance = [];

    public function __set($name, $value)
    {
        $this->instance[$name] = $value;
    }
}

class adapter
{
    public $name = '我是调度器';
}

$container = new container();
$container->adapter = new adapter();

class autofelix
{
    private $container;

    public function __construct(container $container)
    {
        $this->container = $container;
    }

    public function who($class)
    {
        return $this->container->instance[$class]->name;
    }
}

$autofelix = new autofelix($container);

$who = $autofelix->who('adapter');

var_dump($who); //我是调度器
Copy after login

Dependency Injection Advanced Optimization

    above In the application, we
  • directly inject the instantiated objects into the container
  • This will cause all objects to be instantiated before they are used, causing
  • resource loss Loss
  • We can
  • pass in the closure, so that the object will not be instantiated and injected. When you need to use it yourself, instantiate it again, which can reduce Loss of server resources
<?php
$container = new container();
$container->adapter = new adapter();

//高阶优化
$container = new container();
$container->adapter = function () {
    return new adapter();
};
Copy after login
Recommended study: "

PHP Video Tutorial"

The above is the detailed content of An article to talk about DI dependency injection in php. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

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

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

PHP 8.4 Installation and Upgrade guide for Ubuntu and Debian PHP 8.4 Installation and Upgrade guide for Ubuntu and Debian Dec 24, 2024 pm 04:42 PM

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

How To Set Up Visual Studio Code (VS Code) for PHP Development How To Set Up Visual Studio Code (VS Code) for PHP Development Dec 20, 2024 am 11:31 AM

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

7 PHP Functions I Regret I Didn't Know Before 7 PHP Functions I Regret I Didn't Know Before Nov 13, 2024 am 09:42 AM

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

Explain JSON Web Tokens (JWT) and their use case in PHP APIs. Explain JSON Web Tokens (JWT) and their use case in PHP APIs. Apr 05, 2025 am 12:04 AM

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,

How do you parse and process HTML/XML in PHP? How do you parse and process HTML/XML in PHP? Feb 07, 2025 am 11:57 AM

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

PHP Program to Count Vowels in a String PHP Program to Count Vowels in a String Feb 07, 2025 pm 12:12 PM

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

Explain late static binding in PHP (static::). Explain late static binding in PHP (static::). Apr 03, 2025 am 12:04 AM

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 PHP magic methods (__construct, __destruct, __call, __get, __set, etc.) and provide use cases? What are PHP magic methods (__construct, __destruct, __call, __get, __set, etc.) and provide use cases? Apr 03, 2025 am 12:03 AM

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.

See all articles