Dropwizard/Jersey/HK2 Scala 中的依赖注入

Question

尝试创建自定义 @Context 我可以通过 Jersey 注入我的资源。

this question 中的 Java 对此进行了介绍。我已经阅读了也在 Java 中的 docs covering this。最后一些代码涵盖相同的 topic (doing this all through Dropwizard) in Github.

第一部分是创建工厂。

斯卡拉：

import org.glassfish.hk2.api.Factory
import javax.inject.Inject
import javax.ws.rs.container.ContainerRequestContext
import MyObj

class MyObjFactory @Inject()(ctr: ContainerRequestContext) extends Factory[MyObj] {
  private final val context: ContainerRequestContext = ctr

  override def provide(): MyObj = context.getProperty("myObj").asInstanceOf[MyObj]

  override def dispose(myObj: MyObj): Unit = { }
}

下一部分是注册工厂，我假设 classOf[T] 是等同于 Java 的 T.class

的适当 Scala

import org.glassfish.hk2.utilities.binding.AbstractBinder

environment.jersey.register(new AbstractBinder {
  override def configure(): Unit = {
    bindFactory(classOf[MyObjFactory])
        .to(classOf[MyObj])
        .proxy(true)
        .proxyForSameScope(false)
        .in(classOf[RequestScoped])
  }
})

最后应该是实际注入：

@Path("/")
class MyResource {
    @GET
    def get(@Context uriInfo: UriInfo, @Context myObjFactory: MyObjFactory) = {
        // do stuff
    }
}

这一切都编译但在运行时失败，出现以下异常

ERROR [2017-04-05 00:26:14,605] io.dropwizard.jersey.errors.LoggingExceptionMapper: Error handling a request: 8e5877857c823fef
! java.lang.IllegalArgumentException: Invalid injectee with required type of null passed to getInjecteeDescriptor
! ... 87 common frames omitted
! Causing: org.glassfish.hk2.api.MultiException: A MultiException has 1 exceptions.  They are:
! 1. java.lang.IllegalArgumentException: Invalid injectee with required type of null passed to getInjecteeDescriptor
! 
! at org.jvnet.hk2.internal.ServiceLocatorImpl.internalGetInjecteeDescriptor(ServiceLocatorImpl.java:545)
! at org.jvnet.hk2.internal.ServiceLocatorImpl.getInjecteeDescriptor(ServiceLocatorImpl.java:584)
! at org.glassfish.jersey.internal.inject.ContextInjectionResolver.compute(ContextInjectionResolver.java:102)
! at org.glassfish.jersey.internal.inject.ContextInjectionResolver.compute(ContextInjectionResolver.java:98)
! at org.glassfish.hk2.utilities.cache.Cache$OriginThreadAwareFuture.call(Cache.java:97)

无法判断是我在转换为 Scala 时犯了错误，还是我在实际注册 Binder 时做错了什么。

Answer 1

get(@Context uriInfo: UriInfo, @Context myObjFactory: MyObjFactory) <===

您正在尝试注入 Factory。 Factory 用于创建服务。在这种情况下，它并不意味着要被注入。你要注入的是实际的服务，后面会用到工厂来创建

get(@Context uriInfo: UriInfo, @Context myOb: MyObj) <===

Dropwizard/Jersey/HK2 Scala 中的依赖注入

Dropwizard/Jersey/HK2 Dependency Injection in Scala

scala

dependency-injection

jersey

dropwizard

hk2