Jackson scala模块：serialize Enumeration失败 [英] Jackson scala module: serialize Enumeration fails

问题描述

有人可以解释一下为什么这不起作用？
我和杰克逊一起使用Scala模块。

Can someone explain me why this doesn't work? I use the Scala module with Jackson.

我的依赖是com.fasterxml.jackson.module%%jackson- module-scala％2.1.3

我的序列化器是：

import org.bson.types.ObjectId
import com.fasterxml.jackson.databind.module.SimpleModule
import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.module.scala.DefaultScalaModule

object CustomSerializer {

  val objectMapper = new ObjectMapper()

  val module = new SimpleModule("CustomSerializer")
  module.addSerializer(classOf[Throwable], new ThrowableSerializer)
  module.addSerializer(classOf[ObjectId], new ObjectIdSerializer)
  module.addDeserializer(classOf[ObjectId], new ObjectIdDeserializer)
  val scalaModule = DefaultScalaModule

  objectMapper.registerModule(scalaModule)
  objectMapper.registerModule(module)

  def serialize(obj: AnyRef): String = {
    objectMapper.writeValueAsString(obj)
  }

}

<没有什么真正的花哨，我只是将Scala模块添加到默认的序列化器+ MongoDB ObjectId类的一些序列化器。

Nothing really fancy, I just add the Scala module to the default serializer + some serializers for MongoDB ObjectId class.

这是我的简单测试代码：

Here's my simple test code:

@JsonIgnoreProperties(ignoreUnknown = true)
case class Relationship(
                         @Key("_id") id: ObjectId = new ObjectId,
                         fromUserId: ObjectId,
                         fromUserConfiguration: RelationshipConfiguration = new RelationshipConfiguration,
                         toUserId: ObjectId,
                         toUserConfiguration: RelationshipConfiguration = new RelationshipConfiguration,
                        status: RelationshipStatus.Value,
                         ) extends IdentifiableModel[Relationship] {

  ... some methods here
}

    case class SimpleCaseClass(string: String)
    case class SimpleCaseClassWithEnum(string: String,status: RelationshipStatus.Value)

    println(
      CustomSerializer.serialize( SimpleCaseClass("someString") )
    )
    println(
      CustomSerializer.serialize( SimpleCaseClassWithEnum("someString",RelationshipStatus.ACCEPTED) )
    )

    println(
      CustomSerializer.serialize(
        Relationship(
          fromUserId = new ObjectId("510f9398ed5080cb1265c8c2"),
          toUserId = new ObjectId("510f9398ed5080cb1265c8c2"),
          status = RelationshipStatus.ACCEPTED
        )
      )
    )

这会产生输出：

{"string":"someString"}
{"string":"someString","status":{"enumClass":"models.RelationshipStatus","value":"ACCEPTED"}}
[21:35:58] ERROR application - 

! @6e03dp6pp - Internal server error, for (GET) [/me] ->

play.api.UnexpectedException: Unexpected exception[RuntimeException: Cannot resolve type alias Value in models.RelationshipStatus]
    at play.core.ReloadableApplication$$anonfun$get$1$$anonfun$1.apply(ApplicationProvider.scala:142) ~[play_2.10.jar:2.1.0]
    at play.core.ReloadableApplication$$anonfun$get$1$$anonfun$1.apply(ApplicationProvider.scala:106) ~[play_2.10.jar:2.1.0]
    at scala.Option.map(Option.scala:145) ~[scala-library.jar:na]
    at play.core.ReloadableApplication$$anonfun$get$1.apply(ApplicationProvider.scala:106) ~[play_2.10.jar:2.1.0]
    at play.core.ReloadableApplication$$anonfun$get$1.apply(ApplicationProvider.scala:104) ~[play_2.10.jar:2.1.0]
    at scala.util.Either$RightProjection.flatMap(Either.scala:523) [scala-library.jar:na]
    at play.core.ReloadableApplication.get(ApplicationProvider.scala:104) ~[play_2.10.jar:2.1.0]
    at play.core.server.Server$class.sendHandler$1(Server.scala:56) [play_2.10.jar:2.1.0]
    at play.core.server.Server$$anonfun$getHandlerFor$4.apply(Server.scala:88) [play_2.10.jar:2.1.0]
    at play.core.server.Server$$anonfun$getHandlerFor$4.apply(Server.scala:87) [play_2.10.jar:2.1.0]
    at scala.util.Either$RightProjection.flatMap(Either.scala:523) [scala-library.jar:na]
    at play.core.server.Server$class.getHandlerFor(Server.scala:87) [play_2.10.jar:2.1.0]
    at play.core.server.NettyServer.getHandlerFor(NettyServer.scala:34) [play_2.10.jar:2.1.0]
    at play.core.server.netty.PlayDefaultUpstreamHandler.messageReceived(PlayDefaultUpstreamHandler.scala:103) [play_2.10.jar:2.1.0]
    at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:75) [netty.jar:na]
    at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:565) [netty.jar:na]
    at org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendUpstream(DefaultChannelPipeline.java:793) [netty.jar:na]
    at org.jboss.netty.handler.codec.http.HttpContentDecoder.messageReceived(HttpContentDecoder.java:104) [netty.jar:na]
    at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:75) [netty.jar:na]
    at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:565) [netty.jar:na]
    at org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendUpstream(DefaultChannelPipeline.java:793) [netty.jar:na]
    at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:296) [netty.jar:na]
    at org.jboss.netty.handler.codec.frame.FrameDecoder.unfoldAndFireMessageReceived(FrameDecoder.java:455) [netty.jar:na]
    at org.jboss.netty.handler.codec.replay.ReplayingDecoder.callDecode(ReplayingDecoder.java:538) [netty.jar:na]
    at org.jboss.netty.handler.codec.replay.ReplayingDecoder.messageReceived(ReplayingDecoder.java:437) [netty.jar:na]
    at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:75) [netty.jar:na]
    at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:565) [netty.jar:na]
    at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:560) [netty.jar:na]
    at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:268) [netty.jar:na]
    at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:255) [netty.jar:na]
    at org.jboss.netty.channel.socket.nio.NioWorker.read(NioWorker.java:84) [netty.jar:na]
    at org.jboss.netty.channel.socket.nio.AbstractNioWorker.processSelectedKeys(AbstractNioWorker.java:472) [netty.jar:na]
    at org.jboss.netty.channel.socket.nio.AbstractNioWorker.run(AbstractNioWorker.java:333) [netty.jar:na]
    at org.jboss.netty.channel.socket.nio.NioWorker.run(NioWorker.java:35) [netty.jar:na]
    at org.jboss.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:102) [netty.jar:na]
    at org.jboss.netty.util.internal.DeadLockProofWorker$1.run(DeadLockProofWorker.java:42) [netty.jar:na]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) [na:1.7.0_01]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) [na:1.7.0_01]
    at java.lang.Thread.run(Thread.java:722) [na:1.7.0_01]
Caused by: java.lang.RuntimeException: Cannot resolve type alias Value in models.RelationshipStatus
    at org.scalastuff.scalabeans.sig.ScalaTypeCompiler.resolveTypeAlias(ScalaTypeCompiler.scala:202) ~[jackson-module-scala_2.10-2.1.3.jar:na]
    at org.scalastuff.scalabeans.sig.ScalaTypeCompiler.getTypeDecl$1(ScalaTypeCompiler.scala:159) ~[jackson-module-scala_2.10-2.1.3.jar:na]
    at org.scalastuff.scalabeans.sig.ScalaTypeCompiler.resolveScalaType(ScalaTypeCompiler.scala:167) ~[jackson-module-scala_2.10-2.1.3.jar:na]
    at org.scalastuff.scalabeans.sig.ScalaTypeCompiler$$anonfun$3.apply(ScalaTypeCompiler.scala:146) ~[jackson-module-scala_2.10-2.1.3.jar:na]
    at org.scalastuff.scalabeans.sig.ScalaTypeCompiler$$anonfun$3.apply(ScalaTypeCompiler.scala:145) ~[jackson-module-scala_2.10-2.1.3.jar:na]
    at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) ~[scala-library.jar:na]
    at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) ~[scala-library.jar:na]
    at scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59) ~[scala-library.jar:na]
    at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:47) ~[scala-library.jar:na]
    at scala.collection.TraversableLike$class.map(TraversableLike.scala:244) ~[scala-library.jar:na]
    at scala.collection.AbstractTraversable.map(Traversable.scala:105) ~[scala-library.jar:na]
    at org.scalastuff.scalabeans.sig.ScalaTypeCompiler.compile(ScalaTypeCompiler.scala:145) ~[jackson-module-scala_2.10-2.1.3.jar:na]
    at org.scalastuff.scalabeans.sig.ScalaTypeCompiler$$anonfun$1$$anonfun$apply$2.apply(ScalaTypeCompiler.scala:51) ~[jackson-module-scala_2.10-2.1.3.jar:na]
    at org.scalastuff.scalabeans.sig.ScalaTypeCompiler$$anonfun$1$$anonfun$apply$2.apply(ScalaTypeCompiler.scala:48) ~[jackson-module-scala_2.10-2.1.3.jar:na]
    at scala.Option$WithFilter.map(Option.scala:206) ~[scala-library.jar:na]
    at org.scalastuff.scalabeans.sig.ScalaTypeCompiler$$anonfun$1.apply(ScalaTypeCompiler.scala:48) ~[jackson-module-scala_2.10-2.1.3.jar:na]
    at org.scalastuff.scalabeans.sig.ScalaTypeCompiler$$anonfun$1.apply(ScalaTypeCompiler.scala:47) ~[jackson-module-scala_2.10-2.1.3.jar:na]
    at scala.Option.flatMap(Option.scala:170) ~[scala-library.jar:na]
    at org.scalastuff.scalabeans.sig.ScalaTypeCompiler$.classInfoOf(ScalaTypeCompiler.scala:47) ~[jackson-module-scala_2.10-2.1.3.jar:na]
    at org.scalastuff.scalabeans.PropertyDescriptor$$anonfun$4.apply(PropertyDescriptor.scala:225) ~[jackson-module-scala_2.10-2.1.3.jar:na]
    at org.scalastuff.scalabeans.PropertyDescriptor$$anonfun$4.apply(PropertyDescriptor.scala:224) ~[jackson-module-scala_2.10-2.1.3.jar:na]
    at scala.Option.flatMap(Option.scala:170) ~[scala-library.jar:na]
    at org.scalastuff.scalabeans.PropertyDescriptor$.apply(PropertyDescriptor.scala:224) ~[jackson-module-scala_2.10-2.1.3.jar:na]
    at com.fasterxml.jackson.module.scala.util.SmarterBeanIntrospector$.com$fasterxml$jackson$module$scala$util$SmarterBeanIntrospector$$createPropertyDescriptor$1(ScalaBeansUtil.scala:68) ~[jackson-module-scala_2.10-2.1.3.jar:na]
    at com.fasterxml.jackson.module.scala.util.SmarterBeanIntrospector$$anonfun$5$$anonfun$apply$5.apply(ScalaBeansUtil.scala:103) ~[jackson-module-scala_2.10-2.1.3.jar:na]
    at com.fasterxml.jackson.module.scala.util.SmarterBeanIntrospector$$anonfun$5$$anonfun$apply$5.apply(ScalaBeansUtil.scala:94) ~[jackson-module-scala_2.10-2.1.3.jar:na]
    at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) ~[scala-library.jar:na]
    at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244) ~[scala-library.jar:na]
    at scala.collection.IndexedSeqOptimized$class.foreach(IndexedSeqOptimized.scala:33) ~[scala-library.jar:na]
    at scala.collection.mutable.ArrayOps$ofRef.foreach(ArrayOps.scala:105) ~[scala-library.jar:na]
    at scala.collection.TraversableLike$class.map(TraversableLike.scala:244) ~[scala-library.jar:na]
    at scala.collection.mutable.ArrayOps$ofRef.map(ArrayOps.scala:105) ~[scala-library.jar:na]
    at com.fasterxml.jackson.module.scala.util.SmarterBeanIntrospector$$anonfun$5.apply(ScalaBeansUtil.scala:94) ~[jackson-module-scala_2.10-2.1.3.jar:na]
    at com.fasterxml.jackson.module.scala.util.SmarterBeanIntrospector$$anonfun$5.apply(ScalaBeansUtil.scala:93) ~[jackson-module-scala_2.10-2.1.3.jar:na]
    at scala.collection.TraversableLike$$anonfun$flatMap$1.apply(TraversableLike.scala:251) ~[scala-library.jar:na]
    at scala.collection.TraversableLike$$anonfun$flatMap$1.apply(TraversableLike.scala:251) ~[scala-library.jar:na]
    at scala.collection.immutable.List.foreach(List.scala:309) ~[scala-library.jar:na]
    at scala.collection.TraversableLike$class.flatMap(TraversableLike.scala:251) ~[scala-library.jar:na]
    at scala.collection.AbstractTraversable.flatMap(Traversable.scala:105) ~[scala-library.jar:na]
    at com.fasterxml.jackson.module.scala.util.SmarterBeanIntrospector$.apply(ScalaBeansUtil.scala:93) ~[jackson-module-scala_2.10-2.1.3.jar:na]
    at com.fasterxml.jackson.module.scala.util.ScalaBeansUtil$.propertiesOf(ScalaBeansUtil.scala:166) ~[jackson-module-scala_2.10-2.1.3.jar:na]
    at com.fasterxml.jackson.module.scala.deser.CaseClassAnnotationIntrospector$.findConstructorParamName(CaseClassDeserializerModule.scala:51) ~[jackson-module-scala_2.10-2.1.3.jar:na]
    at com.fasterxml.jackson.module.scala.deser.CaseClassAnnotationIntrospector$.findDeserializationName(CaseClassDeserializerModule.scala:41) ~[jackson-module-scala_2.10-2.1.3.jar:na]
    at com.fasterxml.jackson.databind.AnnotationIntrospector.findNameForDeserialization(AnnotationIntrospector.java:915) ~[jackson-databind-2.1.2.jar:2.1.2]
    at com.fasterxml.jackson.databind.introspect.AnnotationIntrospectorPair.findNameForDeserialization(AnnotationIntrospectorPair.java:606) ~[jackson-databind-2.1.2.jar:2.1.2]
    at com.fasterxml.jackson.databind.introspect.POJOPropertiesCollector._addCreators(POJOPropertiesCollector.java:405) ~[jackson-databind-2.1.2.jar:2.1.2]
    at com.fasterxml.jackson.databind.introspect.POJOPropertiesCollector.collect(POJOPropertiesCollector.java:233) ~[jackson-databind-2.1.2.jar:2.1.2]
    at com.fasterxml.jackson.databind.introspect.BasicClassIntrospector.collectProperties(BasicClassIntrospector.java:142) ~[jackson-databind-2.1.2.jar:2.1.2]
    at com.fasterxml.jackson.databind.introspect.BasicClassIntrospector.forSerialization(BasicClassIntrospector.java:68) ~[jackson-databind-2.1.2.jar:2.1.2]
    at com.fasterxml.jackson.databind.introspect.BasicClassIntrospector.forSerialization(BasicClassIntrospector.java:11) ~[jackson-databind-2.1.2.jar:2.1.2]
    at com.fasterxml.jackson.databind.SerializationConfig.introspect(SerializationConfig.java:490) ~[jackson-databind-2.1.2.jar:2.1.2]
    at com.fasterxml.jackson.databind.ser.BeanSerializerFactory.createSerializer(BeanSerializerFactory.java:131) ~[jackson-databind-2.1.2.jar:2.1.2]
    at com.fasterxml.jackson.databind.ser.SerializerFactory.createSerializer(SerializerFactory.java:53) ~[jackson-databind-2.1.2.jar:2.1.2]
    at com.fasterxml.jackson.databind.SerializerProvider._createUntypedSerializer(SerializerProvider.java:935) ~[jackson-databind-2.1.2.jar:2.1.2]
    at com.fasterxml.jackson.databind.SerializerProvider._createAndCacheUntypedSerializer(SerializerProvider.java:892) ~[jackson-databind-2.1.2.jar:2.1.2]
    at com.fasterxml.jackson.databind.SerializerProvider.findValueSerializer(SerializerProvider.java:429) ~[jackson-databind-2.1.2.jar:2.1.2]
    at com.fasterxml.jackson.databind.SerializerProvider.findTypedValueSerializer(SerializerProvider.java:520) ~[jackson-databind-2.1.2.jar:2.1.2]
    at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:99) ~[jackson-databind-2.1.2.jar:2.1.2]
    at com.fasterxml.jackson.databind.ObjectMapper._configAndWriteValue(ObjectMapper.java:2627) ~[jackson-databind-2.1.2.jar:2.1.2]
    at com.fasterxml.jackson.databind.ObjectMapper.writeValueAsString(ObjectMapper.java:2119) ~[jackson-databind-2.1.2.jar:2.1.2]
    at utils.CustomSerializer$.serialize(CustomSerializer.scala:24) ~[na:na]
    at Global$.onStart(Global.scala:36) ~[na:na]
    at play.api.GlobalPlugin.onStart(GlobalSettings.scala:175) ~[play_2.10.jar:2.1.0]
    at play.api.Play$$anonfun$start$1$$anonfun$apply$mcV$sp$1.apply(Play.scala:63) ~[play_2.10.jar:2.1.0]
    at play.api.Play$$anonfun$start$1$$anonfun$apply$mcV$sp$1.apply(Play.scala:63) ~[play_2.10.jar:2.1.0]
    at scala.collection.immutable.List.foreach(List.scala:309) ~[scala-library.jar:na]
    at play.api.Play$$anonfun$start$1.apply$mcV$sp(Play.scala:63) ~[play_2.10.jar:2.1.0]
    at play.api.Play$$anonfun$start$1.apply(Play.scala:63) ~[play_2.10.jar:2.1.0]
    at play.api.Play$$anonfun$start$1.apply(Play.scala:63) ~[play_2.10.jar:2.1.0]
    at play.utils.Threads$.withContextClassLoader(Threads.scala:18) ~[play_2.10.jar:2.1.0]
    at play.api.Play$.start(Play.scala:62) ~[play_2.10.jar:2.1.0]
    at play.core.ReloadableApplication$$anonfun$get$1$$anonfun$1.apply(ApplicationProvider.scala:133) ~[play_2.10.jar:2.1.0]
    ... 38 common frames omitted

因此只有第3个序列化失败。

So only the 3rd serialization fail.

我的枚举是基本的：

object RelationshipStatus extends Enumeration {
  val PENDING = Value("PENDING")
  val ACCEPTED = Value("ACCEPTED")
  val REJECTED = Value("REJECTED")
  val IGNORED = Value("IGNORED")
}

任何想法???
我没有在我的枚举中定义任何类型别名，为什么会出现这个错误？为什么在第3次尝试而不是2日有相同的枚举？

Any idea??? I don't define any type alias in my Enumeration, so why this error? why on the 3rd attempt and not on the 2nd which has the same enum?

顺便说一句，是否有可能：

By the way, is it possible to have:

{"string":"someString","status":"ACCEPTED"}

而不是：

{"string":"someString","status":{"enumClass":"models.RelationshipStatus","value":"ACCEPTED"}}

推荐答案

您有两个不同的问题：

1. 为什么此代码会抛出异常？

1. Why is this code throwing an exception?

我不知道，除了说 scalabeans ，杰克逊斯卡拉2.1系列的库模块依赖，看起来它在Enumerations上有问题，可能特别是在Scala 2.10下。我将在相关的github问题中跟踪此缺陷。

I don't know, other than to say that scalabeans, a library that the 2.1 series of the Jackson Scala module depends, looks like it's having trouble with Enumerations, possibly specifically under Scala 2.10. I'll track this defect in the related github issue.

枚举是否可以在序列化时传达其类型？

Can Enumerations not have to convey their type when serialized?

尚未。详细说明相关github问题的原因;要点是因为Enumerations的Value类型只是类型别名而不是类型，所以每个Enumeration派生类的每个值在Java擦除下都具有相同的运行时类型。

Not yet. Details why are in the relevant github issue; the gist is that since the Value types for Enumerations are just type alias and not types, every value of every Enumeration-derived class has the same runtime type under Java erasure.

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