grails将多个子节点添加到父域

Question

我在向父母添加子域名时遇到一些困难。这是课程：

  class parent{
String firstName
String lastName
String dobYear
String dobMonth
String dobDay
Date dateCreated
Date lastUpdated
long version

static hasMany = [
    chidlren: Children

]

static mapping = {
    cache true
    id generator: 'assigned'

    columns {
        firstName           type:'text'
        lastName            type:'text'
        dobYear             type:'text'
        dobMonth            type:'text'
        dobDay              type:'text'
    }


}
static constraints = {
    firstName           (nullable:true)
    lastName            (nullable:true)     
    dobYear             (nullable:true)
    dobMonth            (nullable:true)
    dobDay              (nullable:true)     
    id              (nullable:false)

}

}

小孩：

   class Children{

String skillId
String skillName    
String skillProficiency
String skillYears       
Date dateCreated
Date lastUpdated
long version

static belongsTo = [parent:Parent]
static mapping = {
    cache true
    columns {       
        skillId      type:'text'
        skillName    type:'text'
        skillProficiency type:'text'            
        skillYears   type:'text'
    }
}
static constraints = {

     skillId                    (nullable:true)
     skillName                  (nullable:true)
     skillProficiency           (nullable:true) 
     skillYears                 (nullable:true) 
}

}

然后我像这样实例化父类：          //我的xml         def feed = new XmlSlurper（）。parseText（linkedinResponse）;

     def newParent= new Parent(
        firstName:"${feed.'first-name'}",
        lastName:"${feed.'last-name'}",
        dobYear :"${feed.'date-of-birth'.'year'}",
        dobMonth:"${feed.'date-of-birth'.'month'}",
        dobDay  :"${feed.'date-of-birth'.'day'}"        

       )
      .id="${feed.id}".toString()

在我的xml feed中，我有多个子节点，所以我想创建多个域节点并将它们添加到父节点。 xml的东西很好用：

  feed.skills.skill.each{ mySkill ->
def newChild = new Children(
              skillId:  mySkill.'id',
              skillName:    mySkill.'name',
              skillProficiency: mySkill.'proficiency',
              skillYears    :   mySkill.'years'
              )
          newParent.addToChildren(newChild )
      }

当我尝试添加子项时，我得到一个错误（o方法的签名：com.myapp.Children.call（）适用于参数类型:(）值：[]）

除了额外字段之外，这与我在grails网站上找到的示例有什么不同，如下所示：

 def parent = new Parent(name:'Dad')
 parent.addToChildren(new Child(name:'son'))
 parent.addToChildren([name:'daughter'])

感谢您的帮助

杰森