单例模式案例

<?php

class Hubby

{

private function __construct() {}

private function __clone() {}

protected static $instance = null;

public static function getInstance()

{

if(is_null(static::$instance)) {

static::$instance = new static();

}

return static::$instance;

}

}

$hubby1 = Hubby::getInstance();

$hubby1 = Hubby::getInstance();

echo ($hubby1 instanceof Hubby)?'是':'不是';

echo '<br>';

echo ($hubby2 instanceof Hubby)?'是':'不是';