Question

我试图将一些数据存储在PostgreSQL数据库中。这可以通过PlayFramework渲染的一个小小的表单来完成。我想测试Slick插件以获得一些使用它的经验，但我遇到了这个例外：

ProvisionException: Unable to provision, see the following errors:

1) Could not find a suitable constructor in services.Consumptions.
Classes must have either one (and only one) constructor annotated with
@Inject or a zero-argument constructor that is not private.
 at services.Consumptions.class(Tables.scala:17)
  while locating services.Consumptions
  for parameter 0 at controllers.HouseSummary.<init>
(HouseSummary.scala:18)
 while locating controllers.HouseSummary
   for parameter 3 at router.Routes.<init>(Routes.scala:39)
  while locating router.Routes
  while locating play.api.inject.RoutesProvider
  while locating play.api.routing.Router
    for parameter 0 at play.api.http.JavaCompatibleHttpRequestHandler.
 <init>(HttpRequestHandler.scala:200)
  while locating play.api.http.JavaCompatibleHttpRequestHandler
  while locating play.api.http.HttpRequestHandler
    for parameter 4 at play.api.DefaultApplication.<init>
(Application.scala:221)
  at play.api.DefaultApplication.class(Application.scala:221)
  while locating play.api.DefaultApplication
  while locating play.api.Application

我做错了什么？我的project/plugins.sbt是：

// The Play plugin
addSbtPlugin("com.typesafe.play" % "sbt-plugin" % "2.5.10")

// web plugins

addSbtPlugin("com.typesafe.sbt" % "sbt-coffeescript" % "1.0.0")

addSbtPlugin("com.typesafe.sbt" % "sbt-less" % "1.1.0")

addSbtPlugin("com.typesafe.sbt" % "sbt-jshint" % "1.0.4")

addSbtPlugin("com.typesafe.sbt" % "sbt-rjs" % "1.0.8")

addSbtPlugin("com.typesafe.sbt" % "sbt-digest" % "1.1.1")

addSbtPlugin("com.typesafe.sbt" % "sbt-mocha" % "1.1.0")

addSbtPlugin("org.irundaia.sbt" % "sbt-sassify" % "1.4.6")

主要问题是这样可以正常工作并保存在PostgreSQL数据库中：

object MyApp extends App {

    val query = TableQuery[Consumptions]
    val db = Database.forConfig("pg-postgres")

    try {
        Await.result(
            db.run(DBIO.seq(query += consumption(0, DateTime.now(), 50.5,50.5,50.5,50.5))), 
            Duration.Inf
        )
    } finally {
        db.close
    }
}

这是控制器：

@Singleton
class HouseSummary @Inject()(consumptions: Consumptions) extends Controller {

  val query = TableQuery[Consumptions]
  val db = Database.forConfig("pg-postgres")

  def add = Action { implicit request =>
    summaryForm.bindFromRequest.fold(
      formWithErrors => {
        // binding failure, you retrieve the form containing errors:
        BadRequest(formWithErrors.toString)
      },
      summaryData => {
        /* binding success, you get the actual value. */
        val newEntry = AddSummaryRequest(
          summaryData.date,
          summaryData.waterconsumption,
          summaryData.electricityheater_1,
          summaryData.electricityheater_2,
          summaryData.electricitymain
        )

        Consumptions.add(newEntry)

        try {
          Await.result(db.run(DBIO.seq(

            query += consumption(
              0,
              new DateTime(newEntry.date),
              summaryData.waterconsumption,
              summaryData.electricityheater_1, summaryData.electricitymain,
              summaryData.electricityheater_2
            )
          )), Duration.Inf)
        } finally db.close

        Ok(s"Erfolgreich gespeichert für das Datum: ${summaryData.date}")
      }
    )
  }

  def summaryForm = Form(
    mapping(
      "date" -> date,
      "waterconsumption" -> of[Double],
      "electricityheater_1" -> of[Double],
      "electricityheater_2" -> of[Double],
      "electricitymain" -> of[Double]
    )(AddSummaryRequest.apply)(AddSummaryRequest.unapply))

}

Answer 1

我发现了错误。我试图注入消耗类，如果要注入的类没有构造函数或类似的东西，那就不起作用，因为guice不知道如何注入这个类。

改变这个：

class HouseSummary @Inject()(consumptions: Consumptions) extends Controller

对此：

class HouseSummary @Inject()() extends Controller

解决了问题

使用Slick，PlayFramework和PostgreSQL启动应用程序时出现异常

1 个答案: