我正在尝试用nodejs和express创建一个简单的hello world路由，当我运行node index.js时，我在控制台中得到listening on port 3000，但当我转到http://localhost:3000/helloworld时，什么都不起作用，它一直在尝试连接。
我可能在路线的某个地方漏掉了什么。
index.js

const express = require("express");
const app = express();
const helloworld_route = require("./routes/helloworld");

const dotenv = require("dotenv");
dotenv.config({ path: "../.env.sample" });
const port = process.env.PORT;

app.use(express.json);

app.listen(port, () => {
  console.log(`Listening on ${process.env.PORT}`);
});

app.use("/", helloworld_route);

controllers/hello.js

const helloTest = (req, res) => {
  res.send("Hello World!");
  console.log("hello");
};

module.exports = {
  helloTest,
};

routes.helloworld.js

const express = require("express");
const router = express.Router();

const HelloWorld = require("../controllers/hello");

router.get("/helloworld", HelloWorld.helloTest);

module.exports = router;