jackson-module-scala将Map中的长键序列化/反序列化为字符串

Question

使用jackson-module-Scala，我尝试使用Long as键序列化和反序列化一个带有内部映射的对象，但是Jackson将键序列化为字符串，如果gnoring类中EKINED的类型，它就不会反序列化为Long。是虫子吗？我做错什么了吗？

import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.module.scala.DefaultScalaModule
import com.fasterxml.jackson.module.scala.experimental.ScalaObjectMapper

case class InnerMap(map: Map[Long, Long])

object CrazyJackson {

  def main(args: Array[String]): Unit = {
    val mapper = new ObjectMapper() with ScalaObjectMapper
    mapper.registerModule(DefaultScalaModule)

    val innerMap = InnerMap(Map(1L->1L))
    val serialized = mapper.writeValueAsString(innerMap)
    val newObj = mapper.readValue(serialized, classOf[InnerMap])
    println(serialized) // Why the key is serialized as a String?
    println(innerMap)
    println(newObj)
    assert(newObj == innerMap)
  }

}

{"map":{"1":1}}

InnerMap(Map(1 -> 1))
InnerMap(Map(1 -> 1))

import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.module.scala.DefaultScalaModule
import com.fasterxml.jackson.module.scala.experimental.ScalaObjectMapper
import org.scalatest.FunSuite

class CrazyJacksonTest extends FunSuite {
  test("test json comparision") {
    val mapper = new ObjectMapper() with ScalaObjectMapper
    mapper.registerModule(DefaultScalaModule)

    val innerMap = InnerMap(Map(1L->1L))
    val serialized = mapper.writeValueAsString(innerMap)
    val newObj = mapper.readValue(serialized, classOf[InnerMap])
    assert(newObj.map == innerMap.map)
  }
}

Map("1" -> 1) did not equal Map(1 -> 1)
ScalaTestFailureLocation: CrazyJacksonTest$$anonfun$1 at (CrazyJacksonTest.scala:17)
Expected :Map(1 -> 1)
Actual   :Map("1" -> 1)

null

• 示例:https://github.com/angelcervera/jackson-scala-map-bug

Answer 1

JSON只允许键名为字符串。ECMA-404 JSON数据交换标准

对象结构表示为围绕零个或多个名称/值对的一对花括号标记。名称是一个字符串。

case class InnerMap(@JsonDeserialize(keyAs = classOf[java.lang.Long])
                    map: Map[Long, Long])