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我有域类结构的特殊情况，其中三个类存在并且它们连接到链：事件 <- 房间 <- 投影仪。（所有关系都是一对一的）

实现看起来像：

class Event {
    Room room
    static constraints = {
        room(nullable:false)
    }
}
class Room {
    Projector projector = new Projector()
    static belongsTo = [event: Event]
    static constraints = {
        projector(nullable:false)
    }
}
class Projector {
    String something = "Something"
    static belongsTo = [room: Room]
    static constraints = {
        room(nullable:false)
    }
}

当我想用新房间创建事件时，我希望默认情况下会创建投影仪：

class TestController {
    def index() {
        Room room = new Room()
        Event event = new Event(room: room)
        event.save(flush: true, failOnError: true)
        render event
    }
}

我收到以下异常

| Error 2012-07-11 16:09:12,541 [http-bio-8080-exec-3] ERROR errors.GrailsExceptionResolver  - TransientObjectException occurred when processing request: [GET] /Test/room/index
object references an unsaved transient instance - save the transient instance before flushing: Projector. Stacktrace follows:
Message: object references an unsaved transient instance - save the transient instance before flushing: Projector
    Line | Method
->>   46 | onApplicationEvent in org.grails.datastore.mapping.engine.event.AbstractPersistenceEventListener
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
|     18 | index              in RoomController
|   1110 | runWorker . . . .  in java.util.concurrent.ThreadPoolExecutor
|    603 | run                in java.util.concurrent.ThreadPoolExecutor$Worker
^    722 | run . . . . . . .  in java.lang.Thread

似乎级联三个类并没有保存默认值。有什么解决办法吗？或者我做错了什么？

4

1 回答 1

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在http://jira.grails.org/browse/GRAILS-4613?attachmentOrder=desc有一个针对您的问题的开放 jira

就我个人而言，我会在我的控制器中处理对象的创建，而不是在域中进行。您需要能够调用projector.save(flush:true)。

于 2012-07-11T19:45:59.133 回答