不能从集合中检索ObjectIds (Scala + MongoDB)

import org.mongodb.scala._
import org.mongodb.scala.bson.ObjectId

object Main extends App {
  // 创建MongoDB连接
  val mongoClient: MongoClient = MongoClient()
  val database: MongoDatabase = mongoClient.getDatabase("mydb")
  val collection: MongoCollection[Document] = database.getCollection("mycollection")

  // 创建ObjectId
  val objectId: ObjectId = new ObjectId()

  // 插入文档
  val document: Document = Document("_id" -> objectId, "name" -> "John")
  collection.insertOne(document).results()

  // 查询文档
  val query: Document = Document("_id" -> objectId)
  val result: Option[Document] = collection.find(query).first().headOption()

  // 打印结果
  result.foreach(println)

  // 关闭连接
  mongoClient.close()
}