安装node

mkdir my-node-server

cd my-node-server

npm init -y

npm install express cors

创建 server.js文件

const express = require('express');

const cors = require('cors');

const app = express();

const PORT = 4000;

app.use(cors()); // 允许跨域请求

app.get('/api/data', (req, res) => {

  res.json({ message: 'Hello from Node.js server!' });

});

app.listen(PORT, () => {

  console.log(`Server is running on http://localhost:${PORT}`);

});

node server.js

访问地址：

http://localhost:5000/api/data

创建react 

npx create-react-app my-react-app

cd my-react-app

src下创建App.js

import React, { useState, useEffect } from 'react';

function App() {

  const [data, setData] = useState(null);

  useEffect(() => {

    fetch('http://localhost:4000/api/data') // 发送网络请求

      .then(response => response.json())

      .then(data => setData(data));

  }, []);

  return (

    <div>

      <h1>React Demo Application</h1>

      <pre>{JSON.stringify(data, null, 2)}</pre>

    </div>

  );

}

export default App;

npm start

http://localhost:3000