


Detailed explanation of PHP singleton mode study notes_PHP tutorial
The singleton mode is a function in PHP that is designed to simplify development and repeated calls. Let me introduce the usage of the singleton mode to you in detail.
1. The concept of singleton pattern
As the name suggests, the singleton pattern has only one instance, and it instantiates itself and provides this instance to the world. What needs to be emphasized is that the singleton pattern
Make sure there can only be one instance of a class!
2. Three key points of singleton pattern
(1) A static variable is needed to save the unique instance of the class
The code is as follows | Copy code | ||||
|
代码如下 | 复制代码 |
private function __construct() |
The code is as follows | Copy code |
private function __construct() |
代码如下 | 复制代码 |
public static function getInstance() { if(! (self::$_instance instanceof self) ) { self::$_instance = new self(); } return self::$_instance; } |
3. Reasons for using singleton mode in php
PHP language is an interpreted scripting language. This operating mechanism allows each PHP page to be interpreted and executed, and all related resources
The sources will be recycled. In other words, PHP has no way to make an object resident in memory at the language level, which is different from asp.net, Java, etc.
Thetypes are different. For example, in Java, singletons will always exist throughout the life cycle of the application. Variables are cross-page level and are truly
To make this instance unique during the application life cycle. However, in PHP, all variables are either global variables or class static
State members are all page-level. Every time the page is executed, a new object will be re-established and will be cleared after the page is executed.
It seems that the PHP singleton mode is meaningless, so I think the PHP singleton mode is only for a single page-level request when multiple
It is very meaningful when the application scenario requires sharing the same object resources.
4. How to implement singleton mode
The code is as follows | Copy code | ||||||||||||||||||||||||
*/
//Private construction method to ensure that the outside world cannot directly instantiate
2. Apply singleton mode to operate the database:
In-depth understanding
There are many design patterns in php, among which the singleton pattern is a more commonly used pattern when we write code. It can not only It is effective enough to reduce the resource consumption of new operations, and it can easily control certain global configuration information! I hope everyone can learn PHP Xi Zhong has a deep understanding of the application of the singleton pattern. 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 UndressAI-powered app for creating realistic nude photos ![]() AI Clothes RemoverOnline AI tool for removing clothes from photos. ![]() Undress AI ToolUndress images for free ![]() Clothoff.ioAI clothes remover ![]() Video Face SwapSwap faces in any video effortlessly with our completely free AI face swap tool! ![]() Hot Article
Assassin's Creed Shadows: Seashell Riddle Solution
3 weeks ago
By DDD
What's New in Windows 11 KB5054979 & How to Fix Update Issues
2 weeks ago
By DDD
Where to find the Crane Control Keycard in Atomfall
3 weeks ago
By DDD
Saving in R.E.P.O. Explained (And Save Files)
1 months ago
By 尊渡假赌尊渡假赌尊渡假赌
![]() Hot Tools![]() Notepad++7.3.1Easy-to-use and free code editor ![]() SublimeText3 Chinese versionChinese version, very easy to use ![]() Zend Studio 13.0.1Powerful PHP integrated development environment ![]() Dreamweaver CS6Visual web development tools ![]() SublimeText3 Mac versionGod-level code editing software (SublimeText3) ![]() Hot Topics
CakePHP Tutorial
![]() ![]() ![]() 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 ![]() 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 ![]() 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 ![]() 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 ![]() 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, ![]() 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. ![]() |