PHP对象、模式与实践之高级特性分析

"; StaticExample::sayHello();

tips:

1.静态方法不能访问类中的普通属性，因为那些属性属于一个对象，但可以访问静态属性。 2.我们不能再对象中调用静态方法，因此不能再静态方法中使用伪变量$this。

静态方法的大例子

title = $title; $this->producerFirstName = $firstName; $this->producerMainName = $mainName; $this->price = $price; } public function setID($id){ $this->id = $id; } public static function getInstance($id,PDO $pdo){ $query = "select * from products where id= '$id'"; $stmt = $pdo->query($query); $row = $stmt->fetch(); if(empty($row)){ return null; } if($row['type'] == "book"){ $product = new BookProduct($row['title'],$row['firstname'],$row['mainname'],$row['price'],$row['numpages'] ); }else if($row['type'] == "cd"){ $product = new CdProduct($row['title'],$row['playLength'] ); }else{ $product = new ShopProduct($row['title'],$row['price'] ); } $product->setId($row['id']); $product->setDiscount($row['discount']); return $product; } 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); } function getProducer(){ return $this->producerFirstName." ".$this->producerMainName; } function getSummaryLine(){ $base = "$this->title({$this->producerMainName},"; $base .= "{$this->producerFirstName})"; return $base; } } class CdProduct extends ShopProduct{ private $playLength; function __construct($title,$price,$playLength){ parent::__construct($title,$price);//继承父类的构造函数 $this->playLength = $playLength; } function getPlayLength(){ return $this->playLength; } function getSummaryLine(){ $base = parent::getSummaryLine(); $base .= ":playing time {$this->playLength}"; return $base; } } class BookProduct extends ShopProduct{ private $numPages = 0; function __construct($title,$numPages){ parent::__construct($title,$price); $this->numPages = $numPages; } function getnumPages(){ return $this->numPages; } function getSummaryLine(){ $base = parent::getSummaryLine(); $base .= ":page count {$this->numPages}"; return $base; } } $dsn = "sqlite:C:/Users/Administrator/Desktop/shop.db"; $pdo = new PDO($dsn,null,null); $pdo->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION); $obj = ShopProduct::getInstance(1,$pdo); echo $obj->getSummaryLine();

更多关于PHP相关内容感兴趣的读者可查看本站专题：《》、《》、《》、《》、《》、《》、《》及《》

希望本文所述对大家PHP程序设计有所帮助。

（编辑：安卓应用网）

【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容!