播放 2.7.x：ProvisionException：无法提供具有循环依赖性的 play.api.Application

Question

从 Play 2.7.x 我无法获得 play.api.Application，我尝试了多种方法，例如来自自定义模块（插件），甚至来自我的 ApplicationController。我总是收到以下循环依赖错误：

ProvisionException: Unable to provision, see the following errors:

1) Found a circular dependency involving play.api.Application, and circular dependencies are disabled.
  at play.api.DefaultApplication.class(Application.scala:252)
  while locating play.api.DefaultApplication
  while locating play.api.Application
    for the 10th parameter of controllers.ApplicationController.<init>(ApplicationController.scala:30)
  while locating controllers.ApplicationController
    for the 2nd parameter of router.Routes.<init>(Routes.scala:111)
  while locating router.Routes
  while locating play.api.inject.RoutesProvider
  while locating play.api.routing.Router
    for the 3rd parameter of play.api.http.DefaultHttpRequestHandler.<init>(HttpRequestHandler.scala:120)
  while locating play.api.http.DefaultHttpRequestHandler
  while locating play.api.http.HttpRequestHandler
    for the 6th parameter of play.api.DefaultApplication.<init>(Application.scala:253)
  at play.api.DefaultApplication.class(Application.scala:252)
  while locating play.api.DefaultApplication
  while locating play.api.Application

1 error

例如，来自我的自定义模块 DynamicTemplateLoader:

@Singleton
class DynamicTemplateLoader @Inject(app: play.api.Application) {
   ...
}

或来自我的 ApplicationController:

class ApplicationController @Inject() (
  components: ControllerComponents
)(
  implicit app: play.api.Application
) extends AbstractController(components) with I18nSupport {
   ...
}

为什么我需要 play.api.Application？我需要掌握 app.classloader 才能使用我的插件的反射。

Answer 1

通过从注入 play.api.Application 的实例切换到注入 javax.inject.Provider[play.api.Application] 的实例来解决问题。

播放 2.7.x：ProvisionException：无法提供具有循环依赖性的 play.api.Application

Play 2.7.x: ProvisionException: Unable to provision play.api.Application with circular dependencies

scala

playframework