在下一个js - File结构中使用多参数的动态路由

const express = require('express');
const app = express();

// 单参数路由示例
app.get('/users/:userId', (req, res) => {
  const userId = req.params.userId;
  res.send(`User ID: ${userId}`);
});

// 多参数路由示例
app.get('/users/:userId/posts/:postId', (req, res) => {
  const userId = req.params.userId;
  const postId = req.params.postId;
  res.send(`User ID: ${userId}, Post ID: ${postId}`);
});

const PORT = process.env.PORT || 3000;
app.listen(PORT, () => {
  console.log(`Server is running on port ${PORT}`);
});

const express = require('express');
const app = express();

// 参数验证中间件
function validateUserId(req, res, next) {
  const userId = req.params.userId;
  if (!userId || isNaN(userId)) {
    return res.status(400).send('Invalid User ID');
  }
  next();
}

app.get('/users/:userId', validateUserId, (req, res) => {
  const userId = req.params.userId;
  res.send(`User ID: ${userId}`);
});

app.listen(3000, () => {
  console.log('Server is running on port 3000');
});

app.get('/users/:userId/posts/:postId', (req, res) => {
  // 处理逻辑
});

app.get('/users/:userId', (req, res) => {
  // 处理逻辑
});