Rapid Web Development with Grails - Learn Java for Web Development - page 299

This will create a new directory called helloworld inside the current one that contains the project, in
other words, your workspace. Navigate to this directory in your console:
cd helloworld
Change into the helloworld directory you just created and start the Grails interactive console by
typing the grails command.
\grails2-workspace\helloworld>grails
This will download several resources, and then you should see a prompt, as illustrated in Figure 7-2 .
Figure 7-2. Grails interactive console
What we want is a simple page that just prints the message “Hello World” to the browser. In Grails,
whenever you want a new page, you create a new controller action for it. Since we don't yet have a
controller, let's create one now with the create-controller command.
grails> create-controller hello
The previous command will create a new controller called HelloController.groovy as illustrated in
Listing 7-1, in the grails-app/controllers/helloworld directory.
Listing 7-1. HelloController.groovy
package helloworld
class HelloController {
def index() { }
}
We now have a controller, so let's add an action to generate the “Hello World” page. The code looks
like Listing 7-2.
Listing 7-2. Modifying the Index Action
def index() { render "Hello World" } }
The action is simply a method. In this particular case, it calls a special method provided by Grails to
render the page.
To see your application in action, you need to start up a server with another command called
run-app .
grails> run-app