abstract：<?php     class Hubby {     private function __construct(){}     private function __clone(){}     protected static $instance = null;

<?php

     class Hubby

 {

     private function __construct(){}

     private function __clone(){}

     protected static $instance = null;

     public static function getInstance()

     {

        if (is_null(static::$instance)){

            static::$instance = new static();

       }

        return static::$instance;

     }

 }

// 從外部來實(shí)例化Hubby類

$hubby1 = Hubby::getInstance();

$hubby2 = Hubby::getInstance();

 echo($hubby1 instanceof Hubby)? '是':'不是';

 echo '<br>';

echo($hubby2 instanceof Hubby)? '是':'不是';

echo '<br>';

echo ($hubby1 === $hubby2) ? '完全相等' : '不相等';

echo '<br>';

var_dump($hubby1,$hubby2);

Correcting teacher：天蓬老師Correction time：2019-01-10 16:40:55
Teacher's summary：js是天生的單例模式, 不過,單例還是很有用的, 不是嗎? php, java都有