PHP对象、模式与实践之高级特性分析
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2024-04-01 21:06:22
本文实例讲述了php面向对象程序设计高级特性。分享给大家供大家参考,具体如下:
高级特性
包括:
1.静态方法和属性(通过类而不是对象来访问数据和功能)
2.抽象类...
本文实例讲述了php面向对象程序设计高级特性。分享给大家供大家参考,具体如下:
高级特性
包括:
1.静态方法和属性(通过类而不是对象来访问数据和功能)
2.抽象类和接口(设计,实现分离)
3.错误处理(异常)
4.final类和方法(限制继承)
5.拦截器(自动委托)
6.析构方法(对象销毁前的清理工作)
7.克隆对象(创建对象的副本)
8.把对象解析成字符串
ps,学会从内存的角度看代码。想象计算机的微观世界。
静态方法的小例子
<?php class staticexample{ static public $anum = 10; static public function sayhello(){ print "hello"; } } print staticexample::$anum."<br/>"; 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
<?php class shopproduct{ private $title; private $producermainname; private $producerfirstname; protected $price; private $discount = 0; private $id = 0; function __construct($title,$firstname,$mainname,$price){ $this->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['firstname'], $row['mainname'], $row['price'], $row['playlength'] ); }else{ $product = new shopproduct($row['title'], $row['firstname'], $row['mainname'], $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,$firstname,$mainname,$price,$playlength){ parent::__construct($title,$firstname,$mainname,$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,$firstname,$mainname,$price,$numpages){ parent::__construct($title,$firstname,$mainname,$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:《php面向对象程序设计入门教程》、《php基本语法入门教程》、《php运算与运算符用法总结》、《php网络编程技巧总结》、《php数组(array)操作技巧大全》、《php字符串(string)用法总结》、《php+mysql数据库操作入门教程》及《php常见数据库操作技巧汇总》
希望本文所述对大家php程序设计有所帮助。
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