PHP工厂模式的日常使用

<?php
class test{
  public $x=1;
  public $setting;
  //负责生成其他对象的类或方法,这就是工厂模式
  public function getsetting(){
    if(!$this->setting){
      $this->setting=new setting();
    }
    return $this->setting;
  }
}
class setting{
  public function __construct(){
    echo 1111;
  }
}
$test=new test();
$setting=$test->getsetting();
$setting2=$test->getsetting();
 
 
//判断两个对象是否是同一个对象
var_dump($setting===$setting2);
//看编号,也能看出来
var_dump($setting);
var_dump($setting2);
 
 
 
 
//属性中有减号的处理
$name="x-b";
$test->$name=2;
 
var_dump($test);
 
 
//$test->x-b;//直接使用上面的属性,会被认为是一个减号
/*
报错:
php notice: use of undefined constant b - assumed 'b' in d:\phpserver\www\test\
test.php on line 11
 
notice: use of undefined constant b - assumed 'b' in d:\phpserver\www\test\test.
php on line 11
 
*/
 
echo $test->{'x-b'}; //这种属性里面有-的这样包一下