[PHP知识库]PHP - 单例模式

1，一个为静态的变量

2，一个为private构造函数

3，一个可以访问实例的静态方法

class Instance
{
    static public $instance = null;
    private function __construct()
    {

    }

    /**
     * 单例模式
     * @return Instance|null
     */
    public static function getInstance()
    {
        if (!self::$instance){
            self::$instance = new self();
        }
        return self::$instance;
    }

    public function getName()
    {
        return '我是单例模式';
    }
}

使用时：

class Instance extends BaseController
{
    public function index()
    {
       $name =  \Instance::getInstance()->getName();
       $name =  \Instance::getInstance()->getName();
       $name =  \Instance::getInstance()->getName();
       $name =  \Instance::getInstance()->getName();
       $name =  \Instance::getInstance()->getName();
       $name =  \Instance::getInstance()->getName();
       $name =  \Instance::getInstance()->getName();
       $name =  \Instance::getInstance()->getName();
       halt($name);
    }