この記事では主に PHP オブジェクト指向の継承の使用法を紹介し、コードの最適化とコードの重複の削減のための例と関連する操作テクニックを使用して PHP オブジェクト指向プログラミングにおける継承の使用法を分析します。例では、PHP でのオブジェクト指向継承の使用について説明します。参考までに皆さんと共有します。詳細は次のとおりです:
継承
まず 2 つのクラスを見てみましょう
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; // 看的页数 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"; ?>
出力:
cd1 ( bobbleson, ） : 再生時間 - 50
book1 (harrelson、harry): ページ数 - 30
コメント: これら 2 つのカテゴリのコードの重複が多すぎ、類似点と相違点があります。プロセスを簡素化するには、継承を使用することをお勧めします。
継承を使用して処理します
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() { // 增加属于自己的方法 return $this->playLength; } function getSummaryLine() { // 改造了父类的方法 $base = "{$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"; ?>
出力:
cd1 (bobbleson, bob): 再生時間 - 50
book1 (harrelson, harry): ページ数 - 30
ポイント コメント: 継承処理により、差異と互換性の問題が非常によく解決されます。
さらなる最適化
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 { // 抽离出属于自己特有的属性 public $playLength; function __construct( $title, $firstName, $mainName, $price, $playLength ) { parent::__construct( $title, $firstName, $mainName, $price ); // 继承父类的构造函数 $this->playLength = $playLength; // 处理自己专有的属性 } 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"; ?>
出力:
cd1 (bobbleson、bob): 再生時間 - 50
book1 (harrelson、harry): ページ数 - 30
: ここに共通を入れます親クラスの属性を管理し、独自のクラスで他の個々の属性を処理します。そして独自の構築メソッドを設定し、親クラスの構築メソッドを継承します。
親クラスのメソッドをさらに継承
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"; ?>
出力:
cd1 (bobbleson, bob): 再生時間 - 50
book1 (harrelson, harry): ページ数 - 30
コメント: 同じ結果を最適化して再度最適化することができます。ここでは親クラスのメソッドが継承されます。親::getsummaryLine()。ただし、これはそれほど頻繁には使用されません。
興味深いコンテンツを追加し続けます
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 ); // 折扣对book无效 print $product2->getSummaryLine(); print "\n"; print "price: {$product2->getPrice()}\n"; ?>
出力:
cd1 (bobbleson、bob): 再生時間 - 50
価格: 1book1 (harrelson、harry): ページ数- 30
price: 4
コメント: book がそれを継承した後、親クラスが割引を追加したため、getPrice メソッドが変更されたため、割引は book に対して無効です。
プライベートプロパティ、メソッドの設定と取得
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"; ?>
出力:
cd1 (bobbleson, bob): 再生時間 - 50
book1 (harrelson, harry): ページ数 - 30
コメント: ここでは属性がさらにプライベート化されており、メソッドを通じてのみ取得できます。これにより安全性が確保されます。
以上がこの記事の全内容です、皆様の学習のお役に立てれば幸いです。
関連推奨事項:
以上がPHP におけるオブジェクト指向継承の使用方法の詳細な説明の詳細内容です。詳細については、PHP 中国語 Web サイトの他の関連記事を参照してください。
![[Web フロントエンド] Node.js クイック スタート](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
