php 单例模式代码-----

singletone.php

class Singletone{

	private static  $obj=null;
	private function __construct(){}

	static function getInstance()
	{
		if(is_null(self::$obj))
		{
			echo 111111111,'------';
			$class = __CLASS__;
			self::$obj=new $class;

		}
		return self::$obj;

	}
}

Singletone::getInstance();
Singletone::getInstance();
Singletone::getInstance();
Singletone::getInstance();