您需要了解 scope 。您已在 beforeFilter（）作用域中初始化了一个变量，然后尝试在 showMe 作用域中使用它。两个是完全不同的。

You need to learn about scope. You have initialised a variable in the beforeFilter() scope and then trying to use it in the showMe scope. The two are completely different.

您可以创建一个范围限定为整个类的变量，通常称为属性...

You can make a variable that is scoped to the entire class, normally called a property...

function beforeFilter() {
   $this->fancyVendor = new fancyVendor();
   $this->fancyVendor->setValue("12");
}

function showMe() {
   echo $this->fancyVendor->getValue();
}

另一点要注意的是，您可以使用 App :: uses（）方法来加载类。根据你的命名它会工作。 （类是以这种方式加载的）

Another point to note is that you can use the App::uses() method to load the class. According to your naming it would work. (class is lazy loaded this way)

App::uses('fancyVendor', 'Vendor');