按嵌套字段查询ReactiveMongo

import reactivemongo.api.collections.bson.BSONCollection
import reactivemongo.api.{DefaultDB, MongoConnection, MongoDriver}
import reactivemongo.bson.{BSONDocument, BSONDocumentReader, BSONDocumentWriter, Macros}

import scala.concurrent.ExecutionContext.Implicits.global
import scala.concurrent.Future

case class User(name: String, age: Int, address: Address)
case class Address(city: String, street: String)

object User {
  implicit val addressHandler: BSONDocumentHandler[Address] = Macros.handler[Address]
  implicit val userHandler: BSONDocumentHandler[User] = Macros.handler[User]
}

object ReactiveMongoExample {
  val mongoUri = "mongodb://localhost:27017/mydb"
  val driver = MongoDriver()
  val parsedUri = MongoConnection.parseURI(mongoUri)
  val connection = parsedUri.map(driver.connection)

  def db: Future[DefaultDB] = connection.flatMap(_.database("mydb"))

  def collection: Future[BSONCollection] = db.map(_.collection("users"))

  def findUsersByCity(city: String): Future[List[User]] = {
    val query = BSONDocument("address.city" -> city)
    collection.flatMap(_.find(query).cursor[User]().collect[List]())
  }
}

// 使用示例
ReactiveMongoExample.findUsersByCity("Shanghai").foreach { users =>
  users.foreach(println)
}