Play framework 2.4、Guice和securesocial

Question

我正在尝试遵循我在http://www.filtercode.com/play/play-scala-securesocial上找到的一个教程。但本教程是针对Play 2.3的。我遇到了一些问题，因为在play版本2.4中，他们从play.api.GlobalSettings中删除了getControllerInstance。如何使用Guice依赖注入来实现所需的相同功能？

    import java.lang.reflect.Constructor
    import securesocial.core.RuntimeEnvironment
    import securesocial.core.providers._
    import securesocial.core.providers.utils.{Mailer, PasswordHasher, PasswordValidator}
    import services.{DemoUserService}
    import models.DemoUser
    import scala.collection.immutable.ListMap

    object Global extends play.api.GlobalSettings {

      /**
       * Demo application's custom Runtime Environment
       */
      object DemoRuntimeEnvironment extends RuntimeEnvironment.Default[DemoUser] {
        override lazy val userService: DemoUserService = new DemoUserService
        override lazy val providers = ListMap(
          include(new FacebookProvider(routes, cacheService, oauth2ClientFor(FacebookProvider.Facebook))),
          include(new GitHubProvider(routes, cacheService, oauth2ClientFor(GitHubProvider.GitHub))),
          include(new GoogleProvider(routes, cacheService, oauth2ClientFor(GoogleProvider.Google))),
          include(new LinkedInProvider(routes, cacheService, oauth1ClientFor(LinkedInProvider.LinkedIn))),
          include(new TwitterProvider(routes, cacheService, oauth1ClientFor(TwitterProvider.Twitter))),
          include(new UsernamePasswordProvider[DemoUser](userService, avatarService, viewTemplates, passwordHashers))
        )
      }

       /**
       * Dependency injection on Controllers using Cake Pattern
       *
       * @param controllerClass
       * @tparam A
       * @return
       */
      override def getControllerInstance[A](controllerClass: Class[A]): A = {
        val instance = controllerClass.getConstructors.find { c =>
          val params = c.getParameterTypes
          params.length == 1 && params(0) == classOf[RuntimeEnvironment[DemoUser]]
        }.map {
          _.asInstanceOf[Constructor[A]].newInstance(DemoRuntimeEnvironment)
        }
        instance.getOrElse(super.getControllerInstance(controllerClass))
      }

    }

如果我删除上面的Cake Pattern代码片段，则会出现错误消息：

ProvisionException: Unable to provision, see the following errors: 
 1) Could not find a suitable constructor in controllers.Application. Classes must have either one (and only one) constructor annotated with @Inject or a zero-argument constructor that is not private. at controllers.Application.class(Application.scala:27) while locating com.google.inject.Provider<controllers.Application> for parameter 1 at router.Routes.<init>(Routes.scala:47) while locating router.Routes while locating play.api.inject.RoutesProvider while locating play.api.routing.Router

 2) Could not find a suitable constructor in securesocial.controllers.LoginPage. Classes must have either one (and only one) constructor annotated with @Inject or a zero-argument constructor that is not private. at securesocial.controllers.LoginPage.class(LoginPage.scala:32) while locating com.google.inject.Provider<securesocial.controllers.LoginPage> for parameter 3 at router.Routes.<init>(Routes.scala:47) while locating router.Routes while locating play.api.inject.RoutesProvider while locating play.api.routing.Router

 3) Could not find a suitable constructor in securesocial.controllers.PasswordChange. Classes must have either one (and only one) constructor annotated with @Inject or a zero-argument constructor that is not private. at securesocial.controllers.PasswordChange.class(PasswordChange.scala:34) while locating com.google.inject.Provider<securesocial.controllers.PasswordChange> for parameter 5 at router.Routes.<init>(Routes.scala:47) while locating router.Routes while locating play.api.inject.RoutesProvider while locating play.api.routing.Router

 4) Could not find a suitable constructor in securesocial.controllers.ProviderController. Classes must have either one (and only one) constructor annotated with @Inject or a zero-argument constructor that is not private. at securesocial.controllers.ProviderController.class(ProviderController.scala:33) while locating com.google.inject.Provider<securesocial.controllers.ProviderController> for parameter 6 at router.Routes.<init>(Routes.scala:47) while locating router.Routes while locating play.api.inject.RoutesProvider while locating play.api.routing.Router

 5) Could not find a suitable constructor in securesocial.controllers.Registration. Classes must have either one (and only one) constructor annotated with @Inject or a zero-argument constructor that is not private. at securesocial.controllers.Registration.class(Registration.scala:37) while locating com.google.inject.Provider<securesocial.controllers.Registration> for parameter 4 at router.Routes.<init>(Routes.scala:47) while locating router.Routes while locating play.api.inject.RoutesProvider while locating play.api.routing.Router

 5 errors

Answer 1

现在SecureSocial不支持依赖注入(JSR330)，在2.4版本中，Play team在消除全局状态方面做了重大改变，使用DI来完成该任务。

关注问题556

更新:正如Jorge指出的那样，从3.0-M4版本开始，Play 2.4被支持。

Answer 2

从3.0-M4开始，您可以使用Play 2.4