To implement the typical "hello world!" example run the
create-controller command:
grails create-controller hello
This will create a new controller (Refer to the section on
Controllers for more information) in the
grails-app/controllers
directory called
HelloController.groovy
.
Controllers are capable of dealing with web requests and to fulfil the "hello world!" use case our implementation needs to look like the following:
class HelloController {
def world = {
render "Hello World!"
}
}
Job done. Now start-up the container with another new command called
run-app:
grails run-app
This will start-up a server on port 8080 and you should now be able to access your application with the URL:
http://localhost:8080/helloworld
The result will look something like the following screenshot:

This is the Grails intro page which is rendered by the
web-app/index.gsp
file. You will note it has a detected the presence of your controller and clicking on the link to our controller we can see the text "Hello World!" printed to the browser window.