PHP五种常用的设计模式——工厂模式
一直对设计模式有一种敬畏之心,每次想要看设计模式的时候就会想到Erich Gamma
,Richard Helm
, Ralph Johnson
, John Vlissides
的黑皮《设计模式》
,基本都望而止步,要把那本书看完可不是一时半会的,而且在没有项目经验的情况下,个人感觉基本都是纸上谈兵。
今天在IBM Developerworks
上看到一篇文章将PHP
中常用的五种设计模式,感觉还不错,而且只有五种五种五种(重要的强调三遍)!先从简单的入手,把这五种消灭了再说。以后慢慢学习其他的设计模式。
工厂模式(Factory Pattern
)
工厂这个词的使用是非常形象,字面意思可以这样认为,这种模式下,我们有一个工厂,这个工厂生产很多一种或者几种产品(其实多种的情况是覆盖了一种的),但是每个产品怎么生产和包装的我们不知道,其实我们也不需要知道,知道的越多你就越迷糊,以后你的行为就受制于太多杂事,也就是我们常说的耦合度太高,因此我们就将所有的事情交给工厂负责,我们只用告诉工厂需要什么,工厂把产品交付给你就是了。一旦产品的工艺发生改变,工厂负责就好,你使用该产品的工艺不受影响。因此工厂模式可以大大的降低系统的耦合度,增强系统的稳定性,当然也会提高代码的复用率。
在实际的程序设计中,工厂相当于一个对外的接口,那么这个接口的返回类型是确定的,那么我们怎么通过这个工厂来生产不同的产品发回给客户呢?很简单,做一个所有产品的“模子”就可以,这个“模子”有每个产品的所有特征,但是不能用,需要具体的产品实现这些特性,就是我们常说的Interface
。
使用类图表示如下:
PHP
的实现
编写一个接口 Product.php
<code class="hljs" java=""><!--?php /** * Created by PhpStorm. * User: Defei * Date: 2015/8/8 * Time: 16:14 */ interface Product{ public function getName(); }</code--></code>
设计一个产品<code>A
实现Product
接口
<code class="hljs" java=""><code class="hljs" xml=""><!--?php /** * Created by PhpStorm. * User: Defei * Date: 2015/8/8 * Time: 16:16 */ class ProductA implements Product{ public function getName(){ // TODO: Implement getName() method. echo '我是产品A'; } }</code--></code></code>
<code class="hljs" xml="">设计产品<code>B
实现Product
接口
<code class="hljs" java=""><code class="hljs" xml=""><code class="hljs" xml=""><!--?php /** * Created by PhpStorm. * User: Defei * Date: 2015/8/8 * Time: 16:17 */ class ProductB implements Product{ public function getName(){ // TODO: Implement getName() method. echo '我是产品B'; } }</code--></code></code></code>
<code class="hljs" xml=""><code class="hljs" xml="">建造一座工厂生产产品<code>A
和B
<code class="hljs" java=""><code class="hljs" xml=""><code class="hljs" xml=""><code class="hljs" java=""><!--?php /** * Created by PhpStorm. * User: Defei * Date: 2015/8/8 * Time: 16:18 */ class ProductFactory{ /** * @param $product_name * @return mixed */ public function factory($product_name){ return new $product_name; //PHP可以使用名字直接new一个同名的对象这个很方便 } }</code--></code></code></code></code>
<code class="hljs" xml=""><code class="hljs" xml=""><code class="hljs" java="">测试
<code class="hljs" xml=""><code class="hljs" xml=""><code class="hljs" java="">产品<code>A
和B
已经设计好了,工厂也建好了,下一步就是测试一下这个工厂对的生产能力如何。
<code class="hljs" java=""><code class="hljs" xml=""><code class="hljs" xml=""><code class="hljs" java=""><code class="hljs" xml=""><!--?php /** * Created by PhpStorm. * User: Defei * Date: 2015/8/8 * Time: 16:20 */ include 'ProductFactory.php'; include 'Product.php'; include 'ProductA.php'; include 'ProductB.php'; $factory = new ProductFactory(); echo $factory--->factory('ProductA')->getName().PHP_EOL; echo $factory->factory('ProductB')->getName(); </code></code></code></code></code>
<code class="hljs" xml=""><code class="hljs" xml=""><code class="hljs" java="">输出结果如下:<br>
<img src="/static/imghwm/default1.png" data-src="http://www.bkjia.com/uploads/allimg/150830/06321MS3-1.png" class="lazy" alt="title=">

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.

In PHP, use the clone keyword to create a copy of the object and customize the cloning behavior through the \_\_clone magic method. 1. Use the clone keyword to make a shallow copy, cloning the object's properties but not the object's properties. 2. The \_\_clone method can deeply copy nested objects to avoid shallow copying problems. 3. Pay attention to avoid circular references and performance problems in cloning, and optimize cloning operations to improve efficiency.

PHP is suitable for web development and content management systems, and Python is suitable for data science, machine learning and automation scripts. 1.PHP performs well in building fast and scalable websites and applications and is commonly used in CMS such as WordPress. 2. Python has performed outstandingly in the fields of data science and machine learning, with rich libraries such as NumPy and TensorFlow.


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