class BookController {
    def list() {
        [books:Book.list()]
    }
}
controllers
Purpose
A plugin that configures core Grails MVC architecture using the underlying Spring MVC component model
Examples
A controller:
A tag library:
import java.text.SimpleDateFormat
class FormatTagLib {
    def dateFormat = { attrs ->
        out << new SimpleDateFormat(attrs.format).format(attrs.value)
    }
}
Description
This plugin configures Grails to use Spring MVC at its core to deal with web requests. The plugin sets up the GrailsDispatcherServlet and necessary Spring beans (see below) for controllers, tag libraries and Groovy Server Pages (GSP)
Configured Spring Beans:
- 
exceptionHandler- An instance of GrailsExceptionResolver for dealing with exceptions - 
groovyPageResourceLoader- Configured indevelopmentmode only or when thegrails.gsp.view.diris set. This is a Spring ResourceLoader that knows how to load GSP views from the an arbitrary location - 
groovyPagesTemplateEngine- An instance of GroovyPagesTemplateEngine, this class deals with rendering of GSP views - 
jspViewResolver- An instance of GrailsViewResolver that knows how to resolve GSP views and is environment aware 
The plugin also configures each Grails controller class as a prototyped Spring bean and each Grails tag library as a singleton Spring bean