Yii2 自定义class、自定义全局函数

1、在appcomponents下新建MyComponent.php

namespace appcomponents;
 
 
use Yii;
use yiiaseComponent;
use yiiaseInvalidConfigException;
 
class MyComponent extends Component
{
 public function welcome()
 {
  echo "Hello..Welcome to MyComponent";
 }
 
}

2、在config/web.php加入你的components

"components" => [
 
         "mycomponent" => [
 
            "class" => "appcomponentsMyComponent",
 
            ],
           ]

3、在controllers/TestController.php中用你的components

namespace appcontrollers;
use Yii;
 
class TestController extends yiiwebController
{
    public function actionWelcome()
    {
       Yii::$app->mycomponent->welcome();
    }
 
}