PHP設計模式——單列模式

<?php

class A
{
  private static $obj;
  private $name;

  private function __construct()
  {

  }

  static public function getObj()
  {
    if (empty(self::$obj)) {
      return self::$obj = new A();
    }
    return self::$obj;
  }

  public function setName($name)
  {
    $this->name = $name;
  }

  public function getName()
  {
    echo $this->name;
  }
}

$a = A::getObj();
$a->setName('test');
$a->getName();
echo '===';
unset($a);
$b = A::getObj();
$b->getName();