单件模式代码测试

<?php
/**
* 单件模式
*/

class DB
{
    private function __construct()
    {

    }

    public static function getInstance()
    {
        static $object;
        if ($object == null) {
            $object = new self();
        }
        return $object;
    }
}

$db1 = DB::getInstance();
$db2 = DB::getInstance();

var_dump($db1);
var_dump($db2);