PHP中實現(xiàn)面向對象編程(上)
Jun 21, 2016 am 09:15 AM編程|對象
這篇文章介紹在PHP的面向對象編程(OOP)。我將演示如何用面向對象的概念編出較少的代碼但更好的程序。祝大家好運。
面向對象編程的概念對每一個作者來說都有不同的看法,我提醒一下一個面向對象語言應有的東西:
- 數(shù)據(jù)抽象和信息隱藏
- 繼承
- 多態(tài)性
在PHP中使用類進行封裝的辦法:
class Something {
// In OOP classes are usually named starting with a cap letter.
var $x;
function setX($v) {
// Methods start in lowercase then use lowercase to seprate
// words in the method name example getValueOfArea()
$this->x=$v;
}
function getX() {
return $this->x;
}
}
?>
當然你可以用你自己的辦法,但有一個標準總是好的。
PHP中類的數(shù)據(jù)成員使用 "var" 定義,數(shù)據(jù)成員是沒有類型直到被賦值。一個數(shù)據(jù)成員可能是一個 integer、數(shù)組、聯(lián)合數(shù)組(associative array)或甚至對象(object). 方法在類里定義成函數(shù),在方法里存取數(shù)據(jù)成員,你必須使用$this->name 這樣的辦法,否則對方法來說是一個函數(shù)的局部變量。
使用 new 來創(chuàng)建一個對象
$obj = new Something;
然后使用成員函數(shù)
$obj->setX(5);
$see = $obj->getX();
setX 成員函數(shù)將 5 賦給對象(而不是類)obj 中成員變量, 然后 getX 返回值 5.
你也可以用對象引用來存取成員變量,例如:$obj->x=6; 然而,這不一種好的面向對象編程的方法。我堅持你應使用成員函數(shù)來設置成員變量的值和通過成員函數(shù)來讀取成員變量。如果你認為成員變量是不可存取的除了使用成員函數(shù)的辦法,你將成為一個好的面向對象程序員。 但不幸的是PHP本身沒有辦法聲明一個變量是私有的,所以允許糟糕的代碼存在。
在 PHP 中繼承使用 extend 來聲明。
class Another extends Something {
var $y;
function setY($v) {
// Methods start in lowercase then use lowercase to seperate
// words in the method name example getValueOfArea()
$this->y=$v;
}
function getY() {
return $this->y;
}
}
?>
這樣類 "Another" 的對象擁有父類的所用成員變量及方法函數(shù),再加上自己的成員變量及成員函數(shù)。如:
$obj2=new Another;
$obj2->setX(6);
$obj2->setY(7);
多重繼承不被支持,所以你不能讓一個類繼承多個類。
在繼承類中你可以重新定義來重定義方法,如果我們在 "Another" 重新定義 getX,那么我們不再能存取 "Something" 中的成員函數(shù) getX. 同樣,如果我們在繼承類中聲明一個和父類同名的成員變量,那么繼承類的變量將隱藏父類的同名變量。
你可以定義一個類的構造函數(shù), 構造函數(shù)是和類同名的成員函數(shù),在你創(chuàng)建類的對象時被調用。
class Something {
var $x;
function Something($y) {
$this->x=$y;
}
function setX($v) {
$this->x=$v;
}
function getX() {
return $this->x;
}
}
?>
所以可以用如下方法創(chuàng)建對象:
$obj=new Something(6);
構造函數(shù)自動賦值 5 給成員變量 x, 構造函數(shù)和成員函數(shù)都是普通的PHP函數(shù),所以你可以使用缺省參數(shù)。
function Something($x="3",$y="5")
然后:
$obj=new Something(); // x=3 and y=5
$obj=new Something(8); // x=8 and y=5
$obj=new Something(8,9); // x=8 and y=9
缺省參數(shù)的定義方法和 C++ 一樣,因此你不能傳一個值給 Y 但讓 X 取缺省值,實參的傳遞是從左到右,當沒有更多的實參時函數(shù)將使用缺省參數(shù)。
只有當繼承類的構造函數(shù)被調用后,繼承類的對象才被創(chuàng)建,父類的構造函數(shù)沒有被調用,這是PHP不同其他面向對象語言的特點,因為構造函數(shù)調用鏈是面向對象編程的特點。如果你想調用基類的構造函數(shù),你不得不在繼承類的構造函數(shù)中顯式調用它。這樣它能工作是因為在繼承類中父類的方法全部可用。
function Another() {
$this->y=5;
$this->Something(); //explicit call to base class constructor.
}
?>
在面向對象編程中一種好的機制是使用抽象類,抽象類是一種不能實例化而是用來給繼承類定義界面的類。設計師經常使用抽象類來強制程序員只能從特定的基類來繼承,所以就能確定新類有所需的功能,但在PHP中沒有標準的辦法做到這一點,不過:
如果你在定義基類是需要這個特點,可以通過在構造函數(shù)中調用 "die",這樣你就可以確保它不能實例化,現(xiàn)在定義抽象類的函數(shù)并在每個函數(shù)中調用 "die",如果在繼承類中程序員不想重定義而直接調用基類的函數(shù),將會產生一個錯誤。
此外,你需要確信因為PHP沒有類型,有些對象是從基類繼承而來的繼承類創(chuàng)建的,因此增加一個方法在基類來辨別類(返回 "一些標識")并驗證這一點,當你收到一個對象作為參數(shù)派上用場。 但對于一個惡棍程序沒用辦法,因為他可以在繼承類中重定義此函數(shù),通常這種辦法只對懶惰的程序員奏效。當然,最好的辦法是防止程序接觸到基類的代碼只提供界面。
重載在PHP中不被支持。在面向對象編程中你可以通過定義不同參數(shù)種類和多少來重載一個同名成員函數(shù)。PHP是一種松散的類型語言,所以參數(shù)類型重載是沒有用的,同樣參數(shù)個數(shù)不同的辦法重載也不能工作。
有時候,在面向對象編程中重載構造函數(shù)很有用,所以你能以不同的方式創(chuàng)建不同的對象(通過傳遞不同的參數(shù)個數(shù))。一個小巧門可以做到這一點:
class Myclass {
function Myclass() {
$name="Myclass".func_num_args();
$this->$name();
//Note that $this->$name() is usually wrong but here
//$name is a string with the name of the method to call.
}
function Myclass1($x) {
code;
}
function Myclass2($x,$y) {
code;
}
}
?>
通過這種辦法可以部分達到重載的目的。
$obj1=new Myclass(1); //Will call Myclass1
$obj2=new Myclass(1,2); //Will call Myclass2
感覺還不錯!

Hot AI Tools

Undress AI Tool
Undress images for free

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Clothoff.io
AI clothes remover

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

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

User voice input is captured and sent to the PHP backend through the MediaRecorder API of the front-end JavaScript; 2. PHP saves the audio as a temporary file and calls STTAPI (such as Google or Baidu voice recognition) to convert it into text; 3. PHP sends the text to an AI service (such as OpenAIGPT) to obtain intelligent reply; 4. PHP then calls TTSAPI (such as Baidu or Google voice synthesis) to convert the reply to a voice file; 5. PHP streams the voice file back to the front-end to play, completing interaction. The entire process is dominated by PHP to ensure seamless connection between all links.

The core method of building social sharing functions in PHP is to dynamically generate sharing links that meet the requirements of each platform. 1. First get the current page or specified URL and article information; 2. Use urlencode to encode the parameters; 3. Splice and generate sharing links according to the protocols of each platform; 4. Display links on the front end for users to click and share; 5. Dynamically generate OG tags on the page to optimize sharing content display; 6. Be sure to escape user input to prevent XSS attacks. This method does not require complex authentication, has low maintenance costs, and is suitable for most content sharing needs.

To realize text error correction and syntax optimization with AI, you need to follow the following steps: 1. Select a suitable AI model or API, such as Baidu, Tencent API or open source NLP library; 2. Call the API through PHP's curl or Guzzle and process the return results; 3. Display error correction information in the application and allow users to choose whether to adopt it; 4. Use php-l and PHP_CodeSniffer for syntax detection and code optimization; 5. Continuously collect feedback and update the model or rules to improve the effect. When choosing AIAPI, focus on evaluating accuracy, response speed, price and support for PHP. Code optimization should follow PSR specifications, use cache reasonably, avoid circular queries, review code regularly, and use X

1. Maximizing the commercial value of the comment system requires combining native advertising precise delivery, user paid value-added services (such as uploading pictures, top-up comments), influence incentive mechanism based on comment quality, and compliance anonymous data insight monetization; 2. The audit strategy should adopt a combination of pre-audit dynamic keyword filtering and user reporting mechanisms, supplemented by comment quality rating to achieve content hierarchical exposure; 3. Anti-brushing requires the construction of multi-layer defense: reCAPTCHAv3 sensorless verification, Honeypot honeypot field recognition robot, IP and timestamp frequency limit prevents watering, and content pattern recognition marks suspicious comments, and continuously iterate to deal with attacks.

PHP does not directly perform AI image processing, but integrates through APIs, because it is good at web development rather than computing-intensive tasks. API integration can achieve professional division of labor, reduce costs, and improve efficiency; 2. Integrating key technologies include using Guzzle or cURL to send HTTP requests, JSON data encoding and decoding, API key security authentication, asynchronous queue processing time-consuming tasks, robust error handling and retry mechanism, image storage and display; 3. Common challenges include API cost out of control, uncontrollable generation results, poor user experience, security risks and difficult data management. The response strategies are setting user quotas and caches, providing propt guidance and multi-picture selection, asynchronous notifications and progress prompts, key environment variable storage and content audit, and cloud storage.

PHP ensures inventory deduction atomicity through database transactions and FORUPDATE row locks to prevent high concurrent overselling; 2. Multi-platform inventory consistency depends on centralized management and event-driven synchronization, combining API/Webhook notifications and message queues to ensure reliable data transmission; 3. The alarm mechanism should set low inventory, zero/negative inventory, unsalable sales, replenishment cycles and abnormal fluctuations strategies in different scenarios, and select DingTalk, SMS or Email Responsible Persons according to the urgency, and the alarm information must be complete and clear to achieve business adaptation and rapid response.

PHPisstillrelevantinmodernenterpriseenvironments.1.ModernPHP(7.xand8.x)offersperformancegains,stricttyping,JITcompilation,andmodernsyntax,makingitsuitableforlarge-scaleapplications.2.PHPintegrateseffectivelyinhybridarchitectures,servingasanAPIgateway

Select the appropriate AI voice recognition service and integrate PHPSDK; 2. Use PHP to call ffmpeg to convert recordings into API-required formats (such as wav); 3. Upload files to cloud storage and call API asynchronous recognition; 4. Analyze JSON results and organize text using NLP technology; 5. Generate Word or Markdown documents to complete the automation of meeting records. The entire process needs to ensure data encryption, access control and compliance to ensure privacy and security.
