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Question

我需要帮助创建域类之间的关联。我有三个域：用户、新闻、评论。一个用户可以在许多新闻上制作许多 cmet。一条新闻可以有来自多个用户的多个 cmets。

我在 GORM 中实现这个关联时遇到了一个大问题。

我希望用户能够将 cmets 添加到新闻项目中。评论应该有对发表评论的用户的引用。并且一个新闻项目应该有一个包含它的所有 cmets 的列表。

领域类：

class User {
    String nickName
    String password
    Date dateCreated
    static hasMany = [users : User, comments : Comment]
    static hasOne = [profile : Profile]
    //static belongsTo = [comments : Comment]

    static constraints = {
        profile nullable: true
    }
}

class News {

    String webTitle
    String webPublicationDate;
    String trailText;
    String webUrl;
    String thumbnail;
    String webId;
    static hasMany = [tags : Tag, comments  : Comment]

    static constraints = {
    }
}

class Comment {
    //static belongsTo = [news : News, user : User]
    String content
    int likes
    int disLikes
    Date lastUpdated
    static hasOne = [user: User, news:  News]

    static constraints = {
    }
}

集成测试包括：

 void "A user can add to a post's comments"(){
    given: "An existing user"
    def newUser = new User(nickName: 'nickName', password: 'password').save(failOnError: true, flush : true)

    and: "A comment and a news"
    def news = new NewsItem(webTitle: 'I Love Hillary', webPublicationDate: new Date(),
            trailText: 'Hillary can change America', webUrl: 'http:google.com', webId: '4', thumbnail: 'image')

    when: 'A user adds comment to post'
    def comm = new Comment(content: "Hillary cant be president", user: newUser, newsItem: news)
    newUser.addToComments(comm)
    news.addToComments(comm)

    then: "NewsItem must have some comments"
    news.comments.size() == 1
    news.comments[0].user == newUser
    newUser.comments.size() == 1
    comm.user == newUser
    news.comments != null
}

任何帮助将不胜感激

Answer 1

我宁愿稍微改变你的域类：

class User {
    String nickName
    String password
    Date dateCreated
    static hasMany = [users : User, comments : Comment]
    static hasOne = [profile : Profile]

    static constraints = {
        profile nullable: true
    }
}

class Communicate { //because News could possibly create troubles during generating controller or test classes (it's the same as singular and plural)
    String webId; 
    String webTitle
    String webPublicationDate;
    String trailText;
    String webUrl;
    String thumbnail;
    static hasMany = [tags : Tag, comments  : Comment]

    static constraints = {
    }

}

class Comment {
    static belongsTo = [user: User, communicate: Communicate] //read more about it: http://docs.grails.org/latest/ref/Domain%20Classes/belongsTo.html
    String content
    int likes
    int disLikes
    Date lastUpdated

    static constraints = {
    }

}

在这些更改之后，您可能应该重新创建这些表（如果仍处于开发阶段，则创建-删除完整数据库）。

此外，通过在 Comment 中添加 belongsTo 语句，您应该修复您的测试（user 和 'communicate' 属性将在创建时是必需的）：

def comm = new Comment(content: "Hillary cant be president", user:user, communicate:news)