//单例模式
//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.在方法里加限制条件
//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";
//$r=ren::duixiang();
//var_dump($r);
//工厂模式
//class YunSuan{
//public $a;
//public $b;
//public function suan(){
//}
//}
//class Jia extends YunSuan{
//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;
//}
//}
//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();
php单例模式与工厂模式
原文地址：http://www.cnblogs.com/p774692352/p/7440634.html