PHP composer 包管理和class类自动载入有什么联系?越详细越好
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PHP composer 包管理和class类自动载入有什么联系?越详细越好
本质而言两者关联不大
自动载入是spl_autoload_register注册的自动载入函数实现(通过重载__autoload函数也可以实现,不过不推荐,这样一来只能有一个autoload函数),你可以自己写这个函数,一般来说需要包括对namespace和class类名的解析,并且把它include进来。所有注册的自动载入函数会在PHP找不到某个类的时候依次触发。(这里的函数是一个callable对象,包括:类方法(动静皆可),Closure闭包(Lambda函数),普通函数)
composer通过每个包的composer.json提供的require的配置来管理包之间的依赖,并且同时它提供了一个autoload的实现来加载这些包下面的类
只要你的代码的类的存储路径是按照PSR-4标准(推荐)和PSR-0标准来规划的,你可以利用composer的autoload来管理你自己的类,这个稍微去翻下composer的文档即可
所以composer是个包管理器,它管理的是包而不是类,不过提供了一个加载这些包内类的autoload实现,但不妨碍你自己实现一个你自己的。
spl_autoload_register: http://php.net/manual/zh/function.spl-autoload-register.php
PSR-4: http://www.php-fig.org/psr/psr-4/ 汉化: https://github.com/PizzaLiu/PHP-FIG/blob/master/PSR-4-autoloader-cn.md
PSR-0: http://www.php-fig.org/psr/psr-0/ 汉化: https://github.com/PizzaLiu/PHP-FIG/blob/master/PSR-0-cn.md
完全两个东西嘛
composer是把你依赖的项目从源安装,举个不是很恰当的例子,Linux系统有很多包都是相互依赖的,当package A以来package B时,B也会安装.
类自动加载是你不大可能只用一个文件或者class就处理完所有业务,比如说MVC架构,不同controller之间可能要相互调用,controllerA.php文件里没有controllerB.php的代码,只能通过类的自动加载实现.将controllerB.php加载进 A 的上下文.
这儿有一篇讲解PHP自动加载机制的可以看看PHP自动加载器

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PHP and Python are both high-level programming languages that are widely used in web development, data processing and automation tasks. 1.PHP is often used to build dynamic websites and content management systems, while Python is often used to build web frameworks and data science. 2.PHP uses echo to output content, Python uses print. 3. Both support object-oriented programming, but the syntax and keywords are different. 4. PHP supports weak type conversion, while Python is more stringent. 5. PHP performance optimization includes using OPcache and asynchronous programming, while Python uses cProfile and asynchronous programming.

PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.

PHP originated in 1994 and was developed by RasmusLerdorf. It was originally used to track website visitors and gradually evolved into a server-side scripting language and was widely used in web development. Python was developed by Guidovan Rossum in the late 1980s and was first released in 1991. It emphasizes code readability and simplicity, and is suitable for scientific computing, data analysis and other fields.

PHP is suitable for web development and rapid prototyping, and Python is suitable for data science and machine learning. 1.PHP is used for dynamic web development, with simple syntax and suitable for rapid development. 2. Python has concise syntax, is suitable for multiple fields, and has a strong library ecosystem.

PHP remains important in the modernization process because it supports a large number of websites and applications and adapts to development needs through frameworks. 1.PHP7 improves performance and introduces new features. 2. Modern frameworks such as Laravel, Symfony and CodeIgniter simplify development and improve code quality. 3. Performance optimization and best practices further improve application efficiency.

PHPhassignificantlyimpactedwebdevelopmentandextendsbeyondit.1)ItpowersmajorplatformslikeWordPressandexcelsindatabaseinteractions.2)PHP'sadaptabilityallowsittoscaleforlargeapplicationsusingframeworkslikeLaravel.3)Beyondweb,PHPisusedincommand-linescrip

PHP type prompts to improve code quality and readability. 1) Scalar type tips: Since PHP7.0, basic data types are allowed to be specified in function parameters, such as int, float, etc. 2) Return type prompt: Ensure the consistency of the function return value type. 3) Union type prompt: Since PHP8.0, multiple types are allowed to be specified in function parameters or return values. 4) Nullable type prompt: Allows to include null values and handle functions that may return null values.


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