grails - Grails “Cannot set readonly property”

Question

我有2个与多对多关系的域，并且这个关系的中间表

class Song implements Taggable {

    static belongsTo = [User]

    static hasMany = [audios: Audio, couplets: Couplet, hasSongListSong: HasSongListSong, hasSublistSong: HasSublistSong]

    String title
    Boolean isChorusRepeat = false
    Boolean deleted = false
    Date dateCreated, lastUpdated

    static constraints = {
        title blank: false, size:1..129
    }
}

class SongList {

    static belongsTo = [User]
    static hasMany = [hasAccess: HasAccess, songListHasSong: HasSongListSong, songSubList: SongSubList]

    String title
    User user
    Boolean deleted = false
    Date dateCreated, lastUpdated

    static constraints = {
        title size: 3..128, blank: false, unique: false
    }
}

带有Song和SongList id的中间表，用于存储关系

class HasSongListSong {

    static belongsTo = [SongList, Song]

    SongList songList
    Song song

    static constraints = {
    }
}

当我尝试在此表中设置数据时，我得到了这个惊喜

def addSongs() {
    def hasSong = new HasSongListSong();
    hasSong.songId = Song.load(1)
    hasSong.songListId = SongList.load(1)
}

第二个问题，如果我从前端范围的id接收到，如何更好地保存这种情况，我的意思是要向 Controller 发出带有songId 1,2，.. n集合的请求。我应该使用一些迭代器，或者有更好的方法？

Answer 1

您不设置ID，而是设置对象:

def addSongs() {
    def hasSong = new HasSongListSong();
    hasSong.song = Song.load(1)
    hasSong.songList = SongList.load(1)
}

在第二个问题中问您一个新问题，我可以尝试回答。