grails create-taglib format
Tag Library Usage
A tag library fulfills role of "view helper" in the Model View Controller (MVC) pattern and helps with GSP rendering. In Grails a tag library is a class with a name that ends in the convention "TagLib" and lives in the grails-app/taglib directory. Use the {commandLineRef}/create-taglib.html[create-taglib] command to create a tag library:
or with your favourite IDE or text editor make a new file with the name FormatTagLib in grails-app/taglib as given below
import java.text.SimpleDateFormat
class FormatTagLib {
def dateFormat = { attrs, body ->
out << new SimpleDateFormat(attrs.format).format(attrs.value)
}
}Each Closure property in a tag library that takes one or two arguments is considered a tag. The first argument (typically named attrs) will contain the attributes of the tag whilst the optional second argument (typically named body) is Closure that represents the inner HTML of the tag declaration from the GSP.