express4.x中路由中间件和挂载路径的关系

express4.x 中一个路由中间件可以挂载到多个路由上，一个路由也可以绑定多个路由中间件，如:

 1 //多个路由匹配一个路由中间件
 2 app.use(['/gre+t', '/hel{2}o'], greet);
 3 
 4 var greet = express.Router();
 5 
 6 greet.get('/jp', function (req, res) {
 7   console.log(req.baseUrl); // /greet
 8   res.send('Konichiwa!');
 9 });
10 
11 app.use('/greet', greet);
12 
13 //多个中间件匹配一个路由
14 app.use('/rtest', [r1, r2]);
15 
16 var r1 = express.Router();
17 r1.get('/', function (req, res, next) {
18   console.log("r1 router");
19   next();
20 })
21 
22 var r2 = express.Router();
23 r2.get('/', function (req, res, next) {
24   console.log('r2 router ');
25   res.send("r2 router " + req.app.get("view engine"))
26   // next();
27 })