app.get('/user/:id', function(req, res){

  res.send('user ' + req.params.id);

}); 

app.get(/^\/users?(?:\/(\d+)(?:\.\.(\d+))?)?/, function(req, res){

  res.send(req.params);

}); 

$ curl http://cssercom:3000/user

[null,null]

$ curl http://cssercom:3000/users

[null,null]

$ curl http://cssercom:3000/users/1

["1",null]

$ curl http://cssercom:3000/users/1..15

["1","15"] 

"/user/:id"

/user/12

 

"/users/:id?"

/users/5

/users

 

"/files/*"

/files/jquery.js

/files/javascripts/jquery.js

 

"/file/*.*"

/files/jquery.js

/files/javascripts/jquery.js

 

"/user/:id/:operation?"

/user/1

/user/1/edit

 

"/products.:format"

/products.json

/products.xml

 

"/products.:format?"

/products.json

/products.xml

/products

 

"/user/:id.:format?"

/user/12

/user/12.json 

var express = require('express')

 , app = express.createServer();

app.use(express.bodyParser());

app.post('/', function(req, res){

 res.send(req.body);

});

app.listen(3000); 

app.get('/users/:id?', function(req, res, next){

  var id = req.params.id;

  if (id) {

    // 一回注：如果在这里就将响应内容输出给客户端，那么后续的URL映射将不会被调用

  } else {

    next(); // 将控制转向下一个符合URL的路由

  }

});

 

app.get('/users', function(req, res){

  // do something else

}); 

var express = require('express')

 , app = express.createServer(); 

var users = [{ name: 'www.csser.com' }];

app.all('/user/:id/:op?', function(req, res, next){

 req.user = users[req.params.id];

 if (req.user) {

  next();

 } else {

  next(new Error('cannot find user ' + req.params.id));

 }

});

app.get('/user/:id', function(req, res){

 res.send('viewing ' + req.user.name);

});

app.get('/user/:id/edit', function(req, res){

 res.send('editing ' + req.user.name);

}); 

app.put('/user/:id', function(req, res){

 res.send('updating ' + req.user.name);

});

app.get('*', function(req, res){

 res.send('what???', 404);

});
app.listen(3000); 

app.get('/user/:userId', function(req, res, next){

 User.get(req.params.userId, function(err, user){

  if (err) return next(err);

  res.send('user ' + user.name);

 });

}); 

app.param('userId', function(req, res, next, id){

 User.get(id, function(err, user){

  if (err) return next(err);

  if (!user) return next(new Error('failed to find user'));

  req.user = user;

  next();

 });

}); 

app.get('/user/:userId', function(req, res){

 res.send('CSSer用户为 ' + req.user.name);

}); 

app.param('number', function(n){ return parseInt(n, 10); }); 

app.param(['from', 'to'], function(n){ return parseInt(n, 10); });