基于 Node.js 的 Express 服务的核心作用

const express = require('express');
const app = express();
// 定义路由
app.get('/api/users', (req, res) => {
  res.json({ users: ['Alice', 'Bob'] });
});

// 示例：记录请求时间的中间件
app.use((req, res, next) => {
  console.log(`Request received at: ${new Date()}`);
  next(); // 传递到下一个中间件或路由
});

const express = require('express');
const app = express();
const port = 3000;
// 使用中间件（如解析 JSON 请求体）
app.use(express.json());
// 定义路由
app.get('/', (req, res) => {
  res.send('Hello World!');
});
// 启动服务
app.listen(port, () => {
  console.log(`Server running at http://localhost:${port}`);
});

const http = require('http');
const server = http.createServer((req, res) => {
  if (req.method === 'GET' && req.url === '/api/users') {
    res.writeHead(200, { 'Content-Type': 'application/json' });
    res.end(JSON.stringify({ users: ['Alice', 'Bob'] }));
  } else {
    res.writeHead(404);
    res.end('Not Found');
  }
});
server.listen(3000);

const express = require('express');
const app = express();
app.get('/api/users', (req, res) => {
  res.json({ users: ['Alice', 'Bob'] });
});
app.listen(3000);