generics - Guice 和 Scala - 泛型依赖注入(inject)

Question

我正在尝试使用 Guice 创建通用特征的绑定(bind)

查看特征是如何定义的

trait Repository[T]

查看trait实现

class DomainRepository extends Repository[Domain]

我在DomainPersistenceModule中的配置方法是:

def configure() {
   bind(classOf[Repository[Domain]])
     .annotatedWith(classOf[DomainDependency])
     .to(classOf[DomainRepository])
     .in(Scopes.SINGLETON)
}

将被注入(inject)依赖的变量是:

  @Inject
  @DomainDependency
  var repository:Repository[Domain] = _

注入(inject)发生在这里:

val injector:Injector = Guice.createInjector(new PersistenceModule())

val persistenceService:PersistenceService =
        injector.getInstance(classOf[DomainPersistenceService])

错误是:

Caused by: com.google.inject.ConfigurationException: Guice configuration errors:

1) No implementation for repository.Repository<domain.Domain> annotated with @module.annotation.DomainDependency() was bound.
  while locating repository.Repository<domain.Domain> annotated with @module.annotation.DomainDependency()
    for field at service.persistence.DomainPersistenceService.repository(DomainPersistenceService.scala:19)
  while locating service.persistence.DomainPersistenceService

我错过了什么吗？提前致谢

Answer 1

您需要一个TypeLiteral像这样绑定(bind):

bind(new TypeLiteral[Repository[Domain]] {})
 .annotatedWith(classOf[DomainDependency])
 .to(classOf[DomainRepository])
 .in(Scopes.SINGLETON)

TypeLiteral 是一个特殊的类，允许您指定完整的参数化类型。基本上，您不能使用泛型类型参数实例化类。

此外，请查看 this answer 。

请参阅“如何使用泛型类型注入(inject)类？”在 Guice FAQ .