<?php
/*
 * WEB开发笔记 www.chhua.com 每日练习之PHP的静态方法与静态属性,只能通过类而不能通过类的实例来访问
 */
class StaticExample {
 static public $name=chenhua;
 static public function write(){
  echo self::$name;//SELF关键字调用静态属性
 }
 
 public function writeName($website){
  echo $website;
 }
}

StaticExample::write();//静态方法
StaticExample::writeName(“www.chhua.com”);//非静态方法
/*一个很经典的把原始数据转换成对象的例子*/
//====================================================================
class Product {//基类
 private  $name;
 private $type;
 protected $jige;
 
 public function __construct($name,$type,$jage){
  $this->name=$name;
  $this->type=$type;
  $this->jige=$jage;
 }
 
 public function getName(){//访问方法
  return $this->name;
 }
 public function getType(){
  return $this->type;
 }
 public function getJiage(){
  return $this->jige;
 }
 
 public function get_zhaiyao(){
  $zhaiyao=$this->name.”({$this->type})<br>价格:{$this->jige}<br>”;
  return $zhaiyao;
 }
}

class BookProduct extends Product {//继承基类
 private $numpages;
 
    public function __construct($name,$type,$jige,$numpages=0){
  parent::__construct($name,$type,$jige);//访问父类的方法
  $this->numpages=$numpages;
 }
 public function getPages(){//独有方法
  return $this->numpages;
 }
 
 public function get_zhaiyao(){//重载方法
  $zhaiyao=parent::get_zhaiyao();//调用父类的方法
  $zhaiyao.=”Page Count-{$this->numpages}页”;
  return $zhaiyao;
 }
}

class CdProduct extends Product{//继承基类
 private $playlength;
 
public function __construct($name,$type,$jiage,$playlength=0){
  parent::__construct($name,$type,$jiage);
  $this->playlength=$playlength;
 }
 public function getTimes (){//独有方法
  return $this->playlength;
 }
 
 public function get_zhaiyao(){//重载方法
  $zhaiyao=parent::get_zhaiyao();//调用父类的方法
  $zhaiyao.=”Play Length-{$this->playlength}分”;
  return $zhaiyao;
 }
}

//====================================================================

//把原始数据转换成对象

class getProduct {
 private $id=0;
 
 public function setId($id){
  $this->id=$id;
 }
 static function getInstance($id,PDO $pdo){
  $sql=”select * from products where id=’$id’”;
  $result=$pdo->query($sql);
  $row=$result->fetch();
  
  if (empty($row)) return null;
  
  if ($row["type"]==”book”){
   $product=new BookProduct($row["name"],
                            $row["type"],
                            $row["jiage"],
                            $row["numpages"]);
  }elseif ($row["type"]==”CD”){
   $product=new CdProduct($row["name"],
                          $row["type"],
                          $row["jiage"],
                          $row["numpages"]);
  }
  return $product;
 }
}
//PDO部分
$dns=”sqlite://home/bob/products.db”;
$pdo=new PDO($dns,null,null);
$pdo->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);
$obj=getProduct::getInstance(1,$pdo);//调用类的静态方法

?>

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本文链接地址: PHP静态方法与静态属性的使用(把纯数据转换成对象的方法) http://www.chhua.com/web-note730

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