erp_yzx/app/api/controller/demo-controller.php

<?php
namespace app\api\controller;

use app\BaseController;

class DemoController extends BaseController
{
    public function index()
    {
        // return json()
    }

    public function hello($name = 'ThinkPHP6')
    {
        return 'hello,' . $name;
    }
}