具有1：N关系的Grails GORM MissingMethodException

I have such domain classes:

我有这样的域类:

class ServicesGroup {
    Long id
    String name
    String description

    String toString(){
        return name
    }

    static mapping = {
        version false
        table 'root.services_groups'

        id column:'group_id' 
        name column:'group_name'
        description column:'group_desc'
    }
}

and

class Step {
    Long id
    ServicesGroup service
    String stepType
    Integer stepFrom
    Integer stepTo

    static constraints = {
        stepType(inList:['operator', 'client'])
    }

    static mapping = {
        version false
        table 'bill.steps'
        service column:'service_group_id'
    }
}

The relationship is - one ServicesGroup entry can have multiple Step instances.

关系是 - 一个ServicesGroup条目可以有多个Step实例。

However, when in my controller I try to

但是,当我在我的控制器中尝试时

Step.findByService(3)

I get:

"org.codehaus.groovy.runtime.InvokerInvocationException: groovy.lang.MissingMethodException: No signature of method: Step.findByService() is applicable for argument types: (java.lang.Integer) values: {3}"

However, when I change Step domain class field

但是,当我更改Step域类字段时

ServicesGroup service

to simply

Long service

it works.

What's going on here?

这里发生了什么?

3 个解决方案

#1

Try it that way:

试试这样:

Step.findByService(ServicesGroup.get(3))

#2

Try

grails clean
grails run-app

Then try again.

然后再试一次。

#3

Something like Step.findByService([id: 3]) may work. It only cares about the ID anyway for the purposes of the SQL generation. In a lot of cases like this you can toss a fake map into there rather than the real thing, and save yourself some performance.

像Step.findByService([id:3])之类的东西可能有效。出于SQL生成的目的,它只关心ID。在很多这样的情况下,你可以将假地图扔到那里而不是真实的地方,并为自己节省一些性能。

On the other hand, the abstraction breaks down a bit when you do this.

另一方面,当你这样做时,抽象会有所破坏。

#1