Question

这是我的代码：

package controllers

import javax.inject.Inject

import scala.concurrent.Future

import play.api.Logger
import play.api.mvc.{ Action, Controller }
import play.api.libs.concurrent.Execution.Implicits.defaultContext
import play.api.libs.functional.syntax._
import play.api.libs.json._

// Reactive Mongo imports
import reactivemongo.api.Cursor
import reactivemongo.api.ReadPreference

import play.modules.reactivemongo.{ // ReactiveMongo Play2 plugin
MongoController,
ReactiveMongoApi,
ReactiveMongoComponents

}

// BSON-JSON conversions/collection
import reactivemongo.play.json._
import play.modules.reactivemongo.json.collection._

/*
 * Example using ReactiveMongo + Play JSON library.
 *
 * There are two approaches demonstrated in this controller:
 * - using JsObjects directly
 * - using case classes that can be turned into JSON using Reads and Writes.
 *
 * This controller uses JsObjects directly.
 *
 * Instead of using the default Collection implementation (which interacts with
 * BSON structures + BSONReader/BSONWriter), we use a specialized
 * implementation that works with JsObject + Reads/Writes.
 *
 * Of course, you can still use the default Collection implementation
 * (BSONCollection.) See ReactiveMongo examples to learn how to use it.
 */
class Application @Inject() (val reactiveMongoApi: ReactiveMongoApi)
  extends Controller with MongoController with ReactiveMongoComponents  {

  def collection: Future[JSONCollection] =
   database.map(_.collection[JSONCollection]("Persons"))

  def index = Action { Ok("works") }

  def create(name: String, age: Int) = Action.async {
    val json = Json.obj(
      "name" -> name,
      "age" -> age,
      "created" -> new java.util.Date().getTime())

    collection.flatMap(_.insert(json)).map(lastError =>
      Ok("Mongo LastError: %s".format(lastError)))
  }
  }

我有一个错误，说无法找到数据库值（数据库是ReactiveMongoApi Trait的成员），所以我想依赖注入有问题。我还在构建sbt中添加了这一行：

添加routesGenerator：= InjectedRoutesGenerator 有任何想法吗？谢谢！

Answer 1

您需要参考注入的API。也就是说，将database替换为reactiveMongoApi.database：

class Application @Inject() (val reactiveMongoApi: ReactiveMongoApi)
  extends Controller with MongoController with ReactiveMongoComponents  {

  def collection: Future[JSONCollection] =
    reactiveMongoApi.database.map(_.collection[JSONCollection]("Persons"))
  ...
}

Play Framework Dependency Injection错误

1 个答案: