laravel_study/app/Http/Controllers/DemoController.php

<?php

namespace App\Http\Controllers;

use App\Events\DemoEvent;
use App\Models\Demo;
use Illuminate\Http\Request;

class DemoController extends Controller
{
    //
    public function index(Demo $demo){
        $all=Demo::find(1);
        event(new DemoEvent($all));
        return View('welcome');
    }
}