Question

如何获取最后插入的ID？我需要获得最新评论ID。请参阅以下代码：

Snoop.findOneById(snoopId) match {
      case Some(snoop) => {
        user.groups.find(ug => ug.groupId == snoop.groupId).map { ug =>
          val prop = Property.findOneById(snoop.propertyId).get
            val comment = Comment(userId = user.id, name=user.getNameString, text = text)
            val snoopSave = snoop.copy(comments = comment :: snoop.comments)
            val sComment = Snoop.save(snoopSave)
        }
        .getOrElse(None)
      }
      case _ => None
    }

Mongodb结构：

{
   "_id": ObjectId("532725c3ff5d00682f5a0b9b"),
   "_t": "models.Snoop",
   "propertyId": ObjectId("532725bfff5d00682f5a0b99"),
   "groupId": ObjectId("529f6461e4b008b565b4358c"),
   "userId": ObjectId("532717e5ff5d00682f5a0b83"),
   "price": 995000,
   "monthlyFees": 0,
   "comments": {
     "0": {
       "_t": "models.Comment",
       "_id": ObjectId("534bce0b7d374bf1b5a170ba"),
       "userId": ObjectId("529f6461e4b008b565b4358b"),
       "name": "monmon",
       "text": "test",
       "createDate": ISODate("2014-04-14T12: 01: 15.627Z"),
       "replies": {
         "0": {
           "_t": "models.Comment",
           "_id": ObjectId("534bd1b67d374bf1b5a170be"),
           "userId": ObjectId("529f6461e4b008b565b4358b"),
           "name": "monmon",
           "text": "monnmonn",
           "createDate": ISODate("2014-04-14T12: 16: 54.752Z"),
           "replies": [

          ] 
        },
         "1": {
           "_t": "models.Comment",
           "_id": ObjectId("534bcf437d374bf1b5a170bc"),
           "userId": ObjectId("529f6461e4b008b565b4358b"),
           "name": "monmon",
           "text": "test test test",
           "createDate": ISODate("2014-04-14T12: 06: 27.896Z"),
           "replies": [

          ] 
        } 
      } 
    } 
  }

另外，我尝试了Get ID of last inserted document in a mongoDB w/ Java driver，但没有效果：

val sComment = Snoop.save(snoopSave)
ObjectId id = (ObjectId)sComment.get( "_id" );

Answer 1

不想回答这个问题，但可能会帮助别人！

- 根据我的研究，mongodb生成的ID是通过客户端完成的，所以不需要查询到服务器端

解决方案＃1 为您的ID分配值

EX: val cID = new Object()

然后将其包含在您的保存代码中

解决方案＃2 让mongodb分配ID

EX: val comment = Comment(userId = user.id, name=user.getNameString, text = text)

然后，这将返回所有信息以及生成的ID。你可以访问 ID通过comment.id（在我的情况下）。

希望这会有助于其他人

使用Play Scala从MongoDB获取最后插入的ID

1 个答案: