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<?php
//设计模式
//单例模式（一个类只能做一个单体模式）
//1.将构造函数变成私有的
//2.提供一个静态方法来返回对象
//3.在方法里面加限制条件
/*class Ren{
private function __construct(){
}
public static function duixiang(){
return new Ren();
}
}
$r = Ren::duixiang();
var_dump($r);*/
/*class Ren{
public $name;
public static $dx;
private function __construct(){
}
public static function duixiang(){
if(empty(Ren::$dx)){
Ren::$dx = new Ren;
}
return Ren::$dx;
}
}
$r = Ren::duixiang();
$r->name = "张三";
$r1 = Ren::duixiang();
var_dump($r);*/
//工厂模式
/*class YunSuan{
public $a;
public $b;
public function jia(){
return $this->a+$this->b;
}
public function jian(){
return $this->a-$this->b;
}
public function cheng(){
return $this->a*$this->b;
}
public function chu(){
return $this->a/$this->b;
}
}*///对类的修改是关闭的，对类的扩展是开放的
/*class YunSuan{
public $a;
public $b;
public function suan(){
}
}//作为父类
class jia extends YunSuan{
public $a;
public $b;
public function suan(){
return $this->a+$this->b;
}
}
class jian extends YunSuan{
public function suan(){
return $this->a-$this->b;
}
}
class Yu extends YunSuan{
public function suan(){
return $this->a%$this->b;
}
}
//工厂类
class GongChang{
public static function duixiang($ysf){
switch($ysf){
case "+";
return new jia();
break;
case "-";
return new jian();
break;
case "%";
return new yu();
break;
}
}
}
$y = GongChang::duixiang("+");
$y->a = 10;
$y->b = 5;
echo $y->suan();*/
?>
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原文：http://www.cnblogs.com/sglq/p/7440554.html