PHP面向?qū)ο罄^承用法詳解(優(yōu)化與減少代碼重復(fù))
更新時(shí)間：2016年12月02日 11:00:25 作者：牛逼的霍嘯林
這篇文章主要介紹了PHP面向?qū)ο罄^承用法,結(jié)合實(shí)例形式分析了php面向?qū)ο蟪绦蛟O(shè)計(jì)中繼承的使用方法及代碼優(yōu)化處理與減少代碼重復(fù)的相關(guān)操作技巧,需要的朋友可以參考下
本文實(shí)例講述了PHP面向?qū)ο罄^承用法。分享給大家供大家參考，具體如下：
繼承
先看兩個(gè)類
<?php
class CdProduct {
public $playLength; // 播放時(shí)間
public $title;
public $producerMainName;
public $producerFirstName;
public $price;
function __construct( $title, $firstName,
$mainName, $price,
$playLength ) {
$this->title = $title;
$this->producerFirstName = $firstName;
$this->producerMainName = $mainName;
$this->price = $price;
$this->playLength = $playLength;
}
function getPlayLength() {
return $this->playLength;
}
function getSummaryLine() {
$base = "{$this->title} ( {$this->producerMainName}, ";
$base .= "{$this->producerFirstName} )";
$base .= ": playing time - {$this->playLength}";
return $base;
}
function getProducer() {
return "{$this->producerFirstName}".
" {$this->producerMainName}";
}
}
class BookProduct {
public $numPages; // 看的頁數(shù)
public $title;
public $producerMainName;
public $producerFirstName;
public $price;
function __construct( $title, $firstName,
$mainName, $price,
$numPages ) {
$this->title = $title;
$this->producerFirstName = $firstName;
$this->producerMainName = $mainName;
$this->price = $price;
$this->numPages = $numPages;
}
function getNumberOfPages() {
return $this->numPages;
}
function getSummaryLine() {
$base = "{$this->title} ( {$this->producerMainName}, ";
$base .= "{$this->producerFirstName} )";
$base .= ": page count - {$this->numPages}";
return $base;
}
function getProducer() {
return "{$this->producerFirstName}".
" {$this->producerMainName}";
}
}
$product1 = new CdProduct("cd1", "bob", "bobbleson", 4, 50 );
print $product1->getSummaryLine();
print "\n";
$product2 = new BookProduct("book1", "harry", "harrelson", 4, 30 );
print $product2->getSummaryLine();
print "\n";
?>
輸出：
cd1 ( bobbleson, bob ): playing time - 50
book1 ( harrelson, harry ): page count - 30
點(diǎn)評(píng)：這兩個(gè)類，代碼重復(fù)性太高，有相同性，也有差異性。不如用繼承來簡化處理。
采用繼承來處理
<?php
class ShopProduct {
public $numPages;
public $playLength;
public $title;
public $producerMainName;
public $producerFirstName;
public $price;
function __construct( $title, $firstName,
$mainName, $price,
$numPages=0, $playLength=0 ) {
$this->title = $title;
$this->producerFirstName = $firstName;
$this->producerMainName = $mainName;
$this->price = $price;
$this->numPages = $numPages;
$this->playLength = $playLength;
}
function getProducer() {
return "{$this->producerFirstName}".
" {$this->producerMainName}";
}
function getSummaryLine() {
$base = "$this->title ( {$this->producerMainName}, ";
$base .= "{$this->producerFirstName} )";
return $base;
}
}
class CdProduct extends ShopProduct {
function getPlayLength() { // 增加屬于自己的方法
return $this->playLength;
}
function getSummaryLine() { // 改造了父類的方法
$base = "{$this->title} ( {$this->producerMainName}, ";
$base .= "{$this->producerFirstName} )";
$base .= ": playing time - {$this->playLength}";
return $base;
}
}
class BookProduct extends ShopProduct {
function getNumberOfPages() {
return $this->numPages;
}
function getSummaryLine() {
$base = "{$this->title} ( {$this->producerMainName}, ";
$base .= "{$this->producerFirstName} )";
$base .= ": page count - {$this->numPages}";
return $base;
}
}
$product1 = new CdProduct("cd1", "bob", "bobbleson", 4, null, 50 );
print $product1->getSummaryLine();
print "\n";
$product2 = new BookProduct("book1", "harry", "harrelson", 4, 30 );
print $product2->getSummaryLine();
print "\n";
?>
輸出：
cd1 ( bobbleson, bob ): playing time - 50
book1 ( harrelson, harry ): page count - 30
點(diǎn)評(píng)：繼承處理很好的解決了差異性，相通性問題。
進(jìn)一步優(yōu)化處理
<?php
class ShopProduct {
// 抽離出共有屬性
public $title;
public $producerMainName;
public $producerFirstName;
public $price;
function __construct( $title, $firstName,
$mainName, $price ) {
$this->title = $title;
$this->producerFirstName = $firstName;
$this->producerMainName = $mainName;
$this->price = $price;
}
function getProducer() {
return "{$this->producerFirstName}".
" {$this->producerMainName}";
}
function getSummaryLine() {
$base = "{$this->title} ( {$this->producerMainName}, ";
$base .= "{$this->producerFirstName} )";
return $base;
}
}
class CdProduct extends ShopProduct {
// 抽離出屬于自己特有的屬性
public $playLength;
function __construct( $title, $firstName,
$mainName, $price, $playLength ) {
parent::__construct( $title, $firstName,
$mainName, $price ); // 繼承父類的構(gòu)造函數(shù)
$this->playLength = $playLength; // 處理自己專有的屬性
}
function getPlayLength() {
return $this->playLength;
}
function getSummaryLine() {
$base = "{$this->title} ( {$this->producerMainName}, ";
$base .= "{$this->producerFirstName} )";
$base .= ": playing time - {$this->playLength}";
return $base;
}
}
class BookProduct extends ShopProduct {
public $numPages;
function __construct( $title, $firstName,
$mainName, $price, $numPages ) {
parent::__construct( $title, $firstName,
$mainName, $price );
$this->numPages = $numPages;
}
function getNumberOfPages() {
return $this->numPages;
}
function getSummaryLine() {
$base = "$this->title ( $this->producerMainName, ";
$base .= "$this->producerFirstName )";
$base .= ": page count - $this->numPages";
return $base;
}
}
$product1 = new CdProduct("cd1", "bob", "bobbleson", 4, 50 );
print $product1->getSummaryLine();
print "\n";
$product2 = new BookProduct("book1", "harry", "harrelson", 4, 30 );
print $product2->getSummaryLine();
print "\n";
?>
輸出：
cd1 ( bobbleson, bob ): playing time - 50
book1 ( harrelson, harry ): page count - 30
點(diǎn)評(píng)：這里把共有屬性在父類中，其他個(gè)性屬性放在自己的類中處理。并設(shè)置自己的構(gòu)造方法，繼承父類的構(gòu)造方法。
進(jìn)一步繼承父類的方法
<?php
class ShopProduct {
public $title;
public $producerMainName;
public $producerFirstName;
public $price;
function __construct( $title, $firstName,
$mainName, $price ) {
$this->title = $title;
$this->producerFirstName = $firstName;
$this->producerMainName = $mainName;
$this->price = $price;
}
function getProducer() {
return "{$this->producerFirstName}".
" {$this->producerMainName}";
}
function getSummaryLine() {
$base = "{$this->title} ( {$this->producerMainName}, ";
$base .= "{$this->producerFirstName} )";
return $base;
}
}
class CdProduct extends ShopProduct {
public $playLength;
function __construct( $title, $firstName,
$mainName, $price, $playLength ) {
parent::__construct( $title, $firstName,
$mainName, $price );
$this->playLength = $playLength;
}
function getPlayLength() {
return $this->playLength;
}
function getSummaryLine() {
$base = parent::getSummaryLine();
$base .= ": playing time - {$this->playLength}";
return $base;
}
}
class BookProduct extends ShopProduct {
public $numPages;
function __construct( $title, $firstName,
$mainName, $price, $numPages ) {
parent::__construct( $title, $firstName,
$mainName, $price );
$this->numPages = $numPages;
}
function getNumberOfPages() {
return $this->numPages;
}
function getSummaryLine() {
$base = parent::getSummaryLine();
$base .= ": page count - {$this->numPages}";
return $base;
}
}
$product1 = new CdProduct("cd1", "bob", "bobbleson", 4, 50 );
print $product1->getSummaryLine();
print "\n";
$product2 = new BookProduct("book1", "harry", "harrelson", 4, 30 );
print $product2->getSummaryLine();
print "\n";
?>
輸出：
cd1 ( bobbleson, bob ): playing time - 50
book1 ( harrelson, harry ): page count - 30
點(diǎn)評(píng)：同樣的結(jié)果，可以優(yōu)化優(yōu)化再優(yōu)化。這里繼承父類的方法。parent::getSummaryLine()。不過這個(gè)用的比較少。
繼續(xù)添加一些有意思的內(nèi)容
<?php
class ShopProduct {
private $title;
private $discount = 0;
private $producerMainName;
private $producerFirstName;
protected $price;
function __construct( $title, $firstName,
$mainName, $price ) {
$this->title = $title;
$this->producerFirstName = $firstName;
$this->producerMainName = $mainName;
$this->price = $price;
}
function setDiscount( $num ) {
$this->discount=$num;
}
function getPrice() {
return ($this->price - $this->discount);
}
function getProducer() {
return "{$this->producerFirstName}".
" {$this->producerMainName}";
}
function getSummaryLine() {
$base = "{$this->title} ( {$this->producerMainName}, ";
$base .= "{$this->producerFirstName} )";
return $base;
}
}
class CdProduct extends ShopProduct {
public $playLength;
function __construct( $title, $firstName,
$mainName, $price, $playLength ) {
parent::__construct( $title, $firstName,
$mainName, $price );
$this->playLength = $playLength;
}
function getPlayLength() {
return $this->playLength;
}
function getSummaryLine() {
$base = parent::getSummaryLine();
$base .= ": playing time - {$this->playLength}";
return $base;
}
}
class BookProduct extends ShopProduct {
public $numPages;
function __construct( $title, $firstName,
$mainName, $price, $numPages ) {
parent::__construct( $title, $firstName,
$mainName, $price );
$this->numPages = $numPages;
}
function getPrice() {
return $this->price;
}
function getNumberOfPages() {
return $this->numPages;
}
function getSummaryLine() {
$base = parent::getSummaryLine();
$base .= ": page count - {$this->numPages}";
return $base;
}
}
$product1 = new CdProduct("cd1", "bob", "bobbleson", 4, 50 );
$product1->setDiscount( 3 );
print $product1->getSummaryLine();
print "\n";
print "price: {$product1->getPrice()}\n";
$product2 = new BookProduct("book1", "harry", "harrelson", 4, 30 );
$product2->setDiscount( 3 ); // 折扣對(duì)book無效
print $product2->getSummaryLine();
print "\n";
print "price: {$product2->getPrice()}\n";
?>
輸出：
cd1 ( bobbleson, bob ): playing time - 50
price: 1
book1 ( harrelson, harry ): page count - 30
price: 4
點(diǎn)評(píng):父類添加了折扣，book繼承之后，修改了getPrice方法，所以折扣對(duì)book無效。
私有化屬性，通過方法來設(shè)置與獲取
<?php
class ShopProduct {
// 私有化屬性，通過方法來設(shè)置與獲取
private $title;
private $producerMainName;
private $producerFirstName;
protected $price;
private $discount = 0;
public function __construct( $title, $firstName,
$mainName, $price ) {
$this->title = $title;
$this->producerFirstName = $firstName;
$this->producerMainName = $mainName;
$this->price = $price;
}
public function getProducerFirstName() {
return $this->producerFirstName;
}
public function getProducerMainName() {
return $this->producerMainName;
}
public function setDiscount( $num ) {
$this->discount=$num;
}
public function getDiscount() {
return $this->discount;
}
public function getTitle() {
return $this->title;
}
public function getPrice() {
return ($this->price - $this->discount);
}
public function getProducer() {
return "{$this->producerFirstName}".
" {$this->producerMainName}";
}
public function getSummaryLine() {
$base = "{$this->title} ( {$this->producerMainName}, ";
$base .= "{$this->producerFirstName} )";
return $base;
}
}
class CdProduct extends ShopProduct {
private $playLength = 0;
public function __construct( $title, $firstName,
$mainName, $price, $playLength ) {
parent::__construct( $title, $firstName,
$mainName, $price );
$this->playLength = $playLength;
}
public function getPlayLength() {
return $this->playLength;
}
public function getSummaryLine() {
$base = parent::getSummaryLine();
$base .= ": playing time - {$this->playLength}";
return $base;
}
}
class BookProduct extends ShopProduct {
private $numPages = 0;
public function __construct( $title, $firstName,
$mainName, $price, $numPages ) {
parent::__construct( $title, $firstName,
$mainName, $price );
$this->numPages = $numPages;
}
public function getNumberOfPages() {
return $this->numPages;
}
public function getSummaryLine() {
$base = parent::getSummaryLine();
$base .= ": page count - {$this->numPages}";
return $base;
}
public function getPrice() {
return $this->price;
}
}
$product1 = new CdProduct("cd1", "bob", "bobbleson", 4, 50 );
print $product1->getSummaryLine()."\n";
$product2 = new BookProduct("book1", "harry", "harrelson", 4, 30 );
print $product2->getSummaryLine()."\n";
?>
輸出：
cd1 ( bobbleson, bob ): playing time - 50
book1 ( harrelson, harry ): page count - 30
點(diǎn)評(píng)：這里進(jìn)一步私有化了屬性，要想獲取只能通過方法。這樣就確保了安全性。
更多關(guān)于PHP相關(guān)內(nèi)容感興趣的讀者可查看本站專題：《php面向?qū)ο蟪绦蛟O(shè)計(jì)入門教程》、《PHP基本語法入門教程》、《PHP運(yùn)算與運(yùn)算符用法總結(jié)》、《PHP網(wǎng)絡(luò)編程技巧總結(jié)》、《PHP數(shù)組(Array)操作技巧大全》、《php字符串(string)用法總結(jié)》、《php+mysql數(shù)據(jù)庫操作入門教程》及《php常見數(shù)據(jù)庫操作技巧匯總》
希望本文所述對(duì)大家PHP程序設(shè)計(jì)有所幫助。
您可能感興趣的文章:
- PHP面向?qū)ο笕筇攸c(diǎn)學(xué)習(xí)(充分理解抽象、封裝、繼承、多態(tài))
- 詳解php中的類與對(duì)象(繼承)
- php面向?qū)ο笕ヂ?（七） 繼承性
- PHP入門教程之面向?qū)ο蟮奶匦苑治?繼承,多態(tài),接口,抽象類,抽象方法等)
- PHP面向?qū)ο蟪绦蛟O(shè)計(jì)高級(jí)特性詳解(接口,繼承,抽象類,析構(gòu),克隆等)
- PHP面向?qū)ο蟪绦蛟O(shè)計(jì)OOP繼承用法入門示例
- PHP面向?qū)ο蟪绦蛟O(shè)計(jì)繼承用法簡單示例
- PHP面向?qū)ο蟪绦蛟O(shè)計(jì)之接口的繼承定義與用法詳解
- PHP學(xué)習(xí)記錄之面向?qū)ο螅∣bject-oriented programming，OOP）基礎(chǔ)【類、對(duì)象、繼承等】
- PHP 對(duì)象繼承原理與簡單用法示例
相關(guān)文章
這篇文章主要為大家詳細(xì)介紹了如何利用PHP實(shí)現(xiàn)餅圖的繪制，文中的示例代碼講解詳細(xì)，具有一定的借鑒價(jià)值，感興趣的小伙伴可以跟隨小編一起學(xué)習(xí)一下2022-12-12
這篇文章主要介紹了php繪制圓形的方法,詳細(xì)分析了php繪制圖形的基本步驟與繪制圓形的實(shí)現(xiàn)方法,需要的朋友可以參考下2015-01-01
PHP實(shí)現(xiàn)按之字形順序打印二叉樹的方法
這篇文章主要介紹了PHP實(shí)現(xiàn)按之字形順序打印二叉樹的方法,涉及php結(jié)合棧遍歷二叉樹的相關(guān)操作技巧,需要的朋友可以參考下2018-01-01
php中刪除數(shù)組的第一個(gè)元素和最后一個(gè)元素的函數(shù)
這篇文章主要介紹了php中刪除數(shù)組的第一個(gè)元素和最后一個(gè)元素的函數(shù),需要的朋友可以參考下2015-03-03
php調(diào)用mysql存儲(chǔ)過程實(shí)例分析
這篇文章主要介紹了php調(diào)用mysql存儲(chǔ)過程,綜合各種常見實(shí)例分析了php調(diào)用mysql存儲(chǔ)過程的各種常見操作與使用技巧,具有一定的參考借鑒價(jià)值,需要的朋友可以參考下2014-12-12
這篇文章主要介紹了PHP序列化操作方法,結(jié)合實(shí)例形式分析了php序列化的原理、實(shí)現(xiàn)方法、相關(guān)函數(shù)與操作技巧,需要的朋友可以參考下2016-09-09
php 啟動(dòng)時(shí)報(bào)錯(cuò)的簡單解決方法
php啟動(dòng)時(shí)報(bào)錯(cuò)的情況，想必很多朋友都有遇到吧，下面為大家介紹下比較不錯(cuò)的解決方法2014-01-01
在本篇文章里小編給大家整理的是一篇關(guān)于php計(jì)算漢明距離總和的實(shí)例講解內(nèi)容，有需要的朋友們可以跟著學(xué)習(xí)參考下。2021-07-07
這篇文章主要介紹了php遞歸遍歷刪除文件的方法,涉及php遍歷文件操作的相關(guān)技巧,非常具有實(shí)用價(jià)值,需要的朋友可以參考下2015-04-04
包括文件讀取函式,文件寫入函式,靜態(tài)頁面生成函式,目錄刪除函式等2009-01-01