php设计模式--工厂模式

/**
 * Created by PhpStorm.
 * User: 17839
 * Date: 2020/3/23
 * Time: 10:54
 */

// 学生类
class Student
{
    public function info()
    {
        echo "我是一名学生";
    }
}

// 老师类
class Teacher
{
    public function info()
    {
        echo "我是一名老师";
    }
}

// 工厂类
class Factory
{
    private static $arr = [];

    public static function getInstance($className)
    {
        if (!isset(self::$arr[$className])) {
            self::$arr[$className] = new $className();
        }
        return self::$arr[$className];
    }
}

// 自动加载（在这里不需要）
spl_autoload_register(function($className){
    $filename = "./$className.class.php";
    if (file_exists($filename)) require_once($filename);
});

$fac = Factory::getInstance("Student");
$fac->info();