无法使用Lumen框架连接到mysql表

'mysql' => [
    'driver' => 'mysql',
    'host' => env('DB_HOST', 'localhost'),
    'port' => env('DB_PORT', '3306'),
    'database' => env('DB_DATABASE', 'database'),
    'username' => env('DB_USERNAME', 'username'),
    'password' => env('DB_PASSWORD', 'password'),
    'charset' => 'utf8mb4',
    'collation' => 'utf8mb4_unicode_ci',
    'prefix' => '',
    'strict' => true,
    'engine' => null,
],

DB_CONNECTION=mysql
DB_HOST=localhost
DB_PORT=3306
DB_DATABASE=database
DB_USERNAME=username
DB_PASSWORD=password

<?php

namespace App\Http\Controllers;

use App\Models\User;
use Illuminate\Http\Request;

class UserController extends Controller
{
    public function index()
    {
        $users = User::all();
        return response()->json($users);
    }
}

<?php

namespace App\Http\Controllers;

use Illuminate\Support\Facades\DB;
use Illuminate\Http\Request;

class UserController extends Controller
{
    public function index()
    {
        $users = DB::table('users')->get();
        return response()->json($users);
    }
}