[英]Jackson scala module: deserialize case object enumeration
我正在使用 Jackson scala 模塊,我需要序列化/反序列化案例 object 枚舉。 序列化工作正常,但是當反序列化返回值時,我得到com.fasterxml.jackson.databind.exc.InvalidDefinitionException
。 有辦法讓它工作嗎? 我想避免使用“經典”scala 枚舉,因為我將失去定義枚舉層次結構的能力。
用於測試的代碼:
import com.fasterxml.jackson.annotation.JsonValue
import com.fasterxml.jackson.databind.{DeserializationFeature, ObjectMapper}
import com.fasterxml.jackson.module.scala.DefaultScalaModule
import com.fasterxml.jackson.module.scala.experimental.ScalaObjectMapper
sealed trait Operations { @JsonValue def jsonValue: String }
case object Foo extends Operations { override def jsonValue: String = "Foo" }
case object Bar extends Operations { override def jsonValue: String = "Bar" }
sealed trait RichOperations extends Operations
case object Baz extends RichOperations { override def jsonValue: String = "Baz" }
object JsonUtils extends App {
val jsonMapper = new ObjectMapper() with ScalaObjectMapper
jsonMapper.registerModule(DefaultScalaModule)
.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false)
def toJson(value: Any): String = jsonMapper.writeValueAsString(value)
def fromJson[T: Manifest](json: String): T = jsonMapper.readValue[T](json)
println(toJson(Foo)) // "Foo"
println(toJson(Bar)) // "Bar"
println(toJson(Baz)) // "Baz"
println(fromJson[Operations](toJson(Foo))) // throws InvalidDefinitionException
println(fromJson[Operations](toJson(Bar)))
println(fromJson[RichOperations](toJson(Baz)))
}
我解決了定義自定義反序列化器的問題。
import com.fasterxml.jackson.core.JsonParser
import com.fasterxml.jackson.databind.{DeserializationContext, JsonDeserializer}
class OperationsDeserializer extends JsonDeserializer[Operations] {
override def deserialize(p: JsonParser, ctxt: DeserializationContext): Operations = {
p.getValueAsString match {
case Foo.jsonValue => Foo
case Bar.jsonValue => Bar
case value => throw new IllegalArgumentException(s"Undefined deserializer for value: $value")
}
}
}
class RichOperationsDeserializer extends JsonDeserializer[Operations] {
override def deserialize(p: JsonParser, ctxt: DeserializationContext): Operations = {
p.getValueAsString match {
case Foo.jsonValue => Foo
case Bar.jsonValue => Bar
case Baz.jsonValue => Baz
case value => throw new IllegalArgumentException(s"Undefined deserializer for value: $value")
}
}
}
此外,由於在匹配/案例中需要穩定的標識符,我將jsonValue
從def
更改為val
:不幸的是,這需要在 object 枚舉的每種情況下聲明@JsonValue
注釋。
import com.fasterxml.jackson.databind.annotation.JsonDeserialize
@JsonDeserialize(using = classOf[OperationsDeserializer])
sealed trait Operations { val jsonValue: String }
case object Foo extends Operations { @JsonValue override val jsonValue: String = "Foo" }
case object Bar extends Operations { @JsonValue override val jsonValue: String = "Bar" }
@JsonDeserialize(using = classOf[RichOperationsDeserializer])
sealed trait RichOperations extends Operations
case object Baz extends RichOperations { @JsonValue override val jsonValue: String = "Baz" }
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.