Specifying a default top-level-page with a route

We need to define a route: a translation rule, which is applied to the URL of the incoming request to a Rails application. Routes are defined in the file config/routes.rb.

In this case, we want to translate an empty URL into a call to the welcome action of the main controller. Add the following line, which must be the first map.connect line in the file:
map.connect '', :controller => "main", :action => "welcome"
This line establishes the rule that will perform the appropriate translation of anempty URL.

注意：To get this default page working correctly, you also have to remove the default default page public/index.html. A best practice is rename it to index.html.hidden, so that it won’t compete for top-level-page status with the main/welcome action.