Grails GORM：绝妙的地图

Question

具有以下域类：

class Word {
    Map translations
    static hasMany = [translations: String]

    String toString(){
        id
    }
}

并且一些实例保存在 grails bootstrap 中：

def word1 = new Word(translations: [en:"game"]);
word1.save(failOnError: true, flush: true)

def word3 = new Word(translations: [en:"gate"]);
word3.save(failOnError: true, flush: true)

def word2 = new Word(translations: [en:"life"]);
word2.save(failOnError: true, flush: true)

无法正确获取 translations 字段。例如：

//input
println Word.findAll().each {
    println it.translations
}
//output
[:]
[:]
[:]
[1, 2, 3]

怎么了？

Answer 1

文档说：

如果你想要一个字符串/值对的简单映射，GORM 可以使用以下命令映射它：

class Author {
    Map books // map of ISBN:book names
}
def a = new Author()
a.books = ["1590597583":"Grails Book"]
a.save()

Answer 2

它应该

static hasMany = [translations: Map]

代替

static hasMany = [translations: String]