单例模式数据库连接对象

<?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();

$hubby2=Hubby::getInstance();

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

echo '<br>';

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

echo '<br>';

echo($hubby1===$hubby2)?'完全相等':'不相等';

echo '<br>';

var_dump($hubby1,$hubby2);