PHP的单例模式

<?php
/**
 * Single.php
 * Created on 2019/8/30 10:03
 * Created by Wilin
 */

class Single
{
    private static $instance;

    //防止直接创建对象
    private function __construct(){}
    //防止克隆
    private function __clone(){}

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