设计模式php篇（一）————单例模式

话不多说，直接上代码：

<?php

namespace DesignPattern;

/**
* php设计模式之单例模式
*/
class SingleInstance
{

	private static $instance = null;

	private function __construct(){}

	public static function getInstance()
	{
		if(is_null(self::$instance)){
			self::$instance = new self();
			return self::$instance;
		}
		else{
			return self::$instance;
		}
	}

}

$instance1 = SingleInstance::getInstance();
var_dump($instance1);
$instance2 = SingleInstance::getInstance();
var_dump($instance2);

/**
打印值为：
/Users/icarus/Code/php/SingleInstance.php:29:
class DesignPattern\SingleInstance#1 (0) {
}
/Users/icarus/Code/php/SingleInstance.php:31:
class DesignPattern\SingleInstance#1 (0) {
}
*/