Question

我想制作一个域对象的副本。实现这一目标的最简单方法是什么？

我意识到我可以创建一个新记录，然后遍历逐个字段复制数据的每个字段 - 但我认为必须有一个更简单的方法来执行此操作...

在Rails中有一种简单的方法：

#rails < 3.1
new_record = old_record.clone

#rails >= 3.1
new_record = old_record.dup

Grails中是否有相应的内容？

Answer 1

我已经修改了一段代码，可以深入克隆域类。我一直在我的系统中使用，它运行得很好（在大多数情况下）。下面的代码是http://grails.1312388.n4.nabble.com/Fwd-How-to-copy-properties-of-a-domain-class-td3436759.html

中的改编版

在我的应用程序中，用户可以选择保存某些类型的对象，并使用deepClone来执行此操作。

您可以指定“不可克隆”属性。为此，您需要使用您不想克隆的属性指定静态地图（在您的类中），例如：

static notCloneable = ['quoteFlows','services']
static hasMany = [quotePacks: QuotePack, services: Service, clients: Client, quoteFlows: QuoteFlow]


static Object deepClone(domainInstanceToClone) {

    //TODO: PRECISA ENTENDER ISSO! MB-249 no youtrack
    //Algumas classes chegam aqui com nome da classe + _$$_javassist_XX
    if (domainInstanceToClone.getClass().name.contains("_javassist"))
        return null

    //Our target instance for the instance we want to clone
    // recursion
    def newDomainInstance = domainInstanceToClone.getClass().newInstance()

    //Returns a DefaultGrailsDomainClass (as interface GrailsDomainClass) for inspecting properties
    GrailsClass domainClass = domainInstanceToClone.domainClass.grailsApplication.getDomainClass(newDomainInstance.getClass().name)

    def notCloneable = domainClass.getPropertyValue("notCloneable")

    for(DefaultGrailsDomainClassProperty prop in domainClass?.getPersistentProperties()) {
        if (notCloneable && prop.name in notCloneable)
            continue

        if (prop.association) {

            if (prop.owningSide) {
                //we have to deep clone owned associations
                if (prop.oneToOne) {
                    def newAssociationInstance = deepClone(domainInstanceToClone?."${prop.name}")
                    newDomainInstance."${prop.name}" = newAssociationInstance
                } else {

                    domainInstanceToClone."${prop.name}".each { associationInstance ->
                        def newAssociationInstance = deepClone(associationInstance)

                        if (newAssociationInstance)
                            newDomainInstance."addTo${prop.name.capitalize()}"(newAssociationInstance)
                    }
                }
            } else {

                if (!prop.bidirectional) {

                    //If the association isn't owned or the owner, then we can just do a  shallow copy of the reference.
                    newDomainInstance."${prop.name}" = domainInstanceToClone."${prop.name}"
                }
                // @@JR
                // Yes bidirectional and not owning. E.g. clone Report, belongsTo Organisation which hasMany
                // manyToOne. Just add to the owning objects collection.
                else {
                    //println "${prop.owningSide} - ${prop.name} - ${prop.oneToMany}"
                    //return
                    if (prop.manyToOne) {

                        newDomainInstance."${prop.name}" = domainInstanceToClone."${prop.name}"
                        def owningInstance = domainInstanceToClone."${prop.name}"
                        // Need to find the collection.
                        String otherSide = prop.otherSide.name.capitalize()
                        //println otherSide
                        //owningInstance."addTo${otherSide}"(newDomainInstance)
                    }
                    else if (prop.manyToMany) {
                        //newDomainInstance."${prop.name}" = [] as Set

                        domainInstanceToClone."${prop.name}".each {

                            //newDomainInstance."${prop.name}".add(it)
                        }
                    }

                    else if (prop.oneToMany) {
                        domainInstanceToClone."${prop.name}".each { associationInstance ->
                            def newAssociationInstance = deepClone(associationInstance)
                            newDomainInstance."addTo${prop.name.capitalize()}"(newAssociationInstance)
                        }
                    }
                }
            }
        } else {
            //If the property isn't an association then simply copy the value
            newDomainInstance."${prop.name}" = domainInstanceToClone."${prop.name}"

            if (prop.name == "dateCreated" || prop.name == "lastUpdated") {
                newDomainInstance."${prop.name}" = null
            }
        }
    }

    return newDomainInstance
}

Answer 2

没有。已经要求http://jira.grails.org/browse/GRAILS-3532。有人在这个问题上添加了一些可能对你有帮助的代码。

如何在Grails中复制域对象？

2 个答案: