<?php /** * 单例模式实现 */ class singleton { //静态变量保存全局实例 private static $instance = null; private function __clone() { //私有构造函数,防止外界实例化对象 } private function __construct() { //私有克隆函数,防止外界克隆对象 } //静态方法,单例统一访问入口 public static function getinstance() { if (self::$instance instanceof singleton) { echo "return exist instance\n"; return self::$instance; } self::$instance = new singleton(); echo "return new instance\n"; return self::$instance; } } $a = singleton::getinstance();//output: return new instance $a = singleton::getinstance();//output: return exist instance
如对本文有疑问, 点击进行留言回复!!
网友评论