nils petersohn nils petersohn - 3 months ago 57
Groovy Question

Binding a Grails date from params in a controller

Why is it so hard to extract the date from the view via the params in a grails controller?

I don't want to extract the date by hand like this:

instance.dateX = parseDate(params["dateX_value"])//parseDate is from my helper class


I just want to use
instance.properties = params
.

In the model the type is
java.util.Date
and in the params is all the information:
[dateX_month: 'value', dateX_day: 'value', ...]


I searched on the net and found nothing on this. I hoped that Grails 1.3.0 could help but still the same thing.

I can't and will not believe that extracting the date by hand is necessary!

Answer

Grails Version >= 2.3

A setting in Config.groovy defines the date formats which will be used application-wide when binding params to a Date

grails.databinding.dateFormats = [
        'MMddyyyy', 'yyyy-MM-dd HH:mm:ss.S', "yyyy-MM-dd'T'hh:mm:ss'Z'"
]

The formats specified in grails.databinding.dateFormats will be attempted in the order in which they are included in the List.

You can override these application-wide formats for an individual command object using @BindingFormat

import org.grails.databinding.BindingFormat

class Person { 
    @BindingFormat('MMddyyyy') 
    Date birthDate 
}

Grails Version < 2.3

i can't and will not belief that extracting the date by hand is nessesary!

Your stubbornness is rewarded, it has been possible to bind a date directly since long before Grails 1.3. The steps are:

(1) Create a class that registers an editor for your date format

import org.springframework.beans.PropertyEditorRegistrar
import org.springframework.beans.PropertyEditorRegistry
import org.springframework.beans.propertyeditors.CustomDateEditor
import java.text.SimpleDateFormat

public class CustomDateEditorRegistrar implements PropertyEditorRegistrar {

    public void registerCustomEditors(PropertyEditorRegistry registry) {

        String dateFormat = 'yyyy/MM/dd'
        registry.registerCustomEditor(Date, new CustomDateEditor(new SimpleDateFormat(dateFormat), true))
    }
}

(2) Make Grails aware of this date editor by registering the following bean in grails-app/conf/spring/resources.groovy

beans = {
    customPropertyEditorRegistrar(CustomDateEditorRegistrar)
}

(3) Now when you send a date in a parameter named foo in the format yyyy/MM/dd it will automatically be bound to a property named foo using either:

myDomainObject.properties = params

or

new MyDomainClass(params)