Grails数据绑定

Question

A Grails controller received is called with the following request parameters:

defaultPrice[0].amount  22
defaultPrice[0].currency 1
defaultPrice[0].id  
defaultPrice[1].amount  33
defaultPrice[1].currency 3
defaultPrice[1].id  

I've defined the following command class:

class PriceCommand {
    BigDecimal amount
    Integer currency
    Integer id
}

I attempt to bind the request parameters to a `List' in the action

def save = {List<PriceCommand> defaultPrice ->

}

But within the action, defaultPrice is null.

Answer 1

It requires an command with existing list of data, with specified name, that will be filled with data from request.

Try

import org.apache.commons.collections.ListUtils
import org.apache.commons.collections.Factory

class PriceListCommand {
   List<PriceCommand> defaultPrice = ListUtils.lazyList([], {new PriceCommand()} as Factory)
}

and use this command inside controller. It should works

Answer 2

I'm not sure if this is what your looking but it may help...

1.) I think indexed params only work if you have a parent-child or one-to-many relationship. For example you might need to introduce a PriceCommandParent which contains a list of PriceCommand . I may be wrong on this and I welcome any corrections.

2.) I've found that indexed params aren't as magically as some of the other areas of Grails/Groovy so sometimes i'd rather deal with the mapping myself. Below is how i've handled it in the past....

def things = []

params.each{name, value->
    if (name.matches('^(thing\\[\\d+\\])$')){ //<-- look for 'thing[x]'
        things.add(new Thing(params[name]);
    }   
}

Let me know if any of this is of help