<?php class="" singleton="" {="" private="" static="" $instance;="" private="" function="" __construct()="" {="" 私有化构造函数,防止外部创建实例="" }="" public="" static="" function="" getinstance()="" {="" if="" (!isset(self::$instance))="" {="" self::$instance="new" singleton();="" }="" return="" self::$instance;="" }="" public="" function="" dosomething()="" {="" echo="" "doing="" something...\n";="" }="" }="" 使用示例="" $instance1="Singleton::getInstance();" $instance1-=""?>doSomething(); $instance2 = Singleton::getInstance(); $instance2->doSomething(); var_dump($instance1 === $instance2); // 输出 true,表示$instance1和$instance2是同一个实例 ?>