This module needs to be used along with jackson-datatype-jsr310 JavaTimeModule. What this module does is to convert Scala FiniteDurations into Java Time Durations and vice versa. JavaTimeModule then does the rest.

• jackson-module-scala-duration 3.x supports Jackson 3
  • 3.x supports Scala 2.12, 2.13 and 3.
  • jackson-datatype-jsr310 is bundled with jackson-databind 3 so you don't need to add a separate dependency
• jackson-module-scala-duration 2.x supports Jackson 2
  • 2.x supports Scala 2.11, 2.12, 2.13 and 3.
  • you need to also add a dependency on com:fasterxml.jackson.datatype:jackson-datatype-jsr310

If you need to support Scala classes generally, you will also need to add jackson-module-scala.

If you don't use this module, Scala FiniteDurations can still be serialized but they will appear in a format like:

{"length":7,"unit":"DAYS","finite":true}

The format seems to differ depending on Scala version (because the internals of the FiniteDuration class can change from release to release). Deserialization seems to be problematic regardless of Scala version.

When this module is used, the serialization format defaults to writing durations as numbers. The format can be changed by enabling/disabling these jackson-datatype-jsr310 features:

• SerializationFeature.WRITE_DURATIONS_AS_TIMESTAMPS
  • if you disable this, the format used is ISO-8601 format (eg 'PT12H' for 12 hours)
• SerializationFeature.WRITE_DATE_TIMESTAMPS_AS_NANOSECONDS appears to have no effect on durations
• DeserializationFeature.READ_DATE_TIMESTAMPS_AS_NANOSECONDS appears to have no effect on durations

Jackson 2 example:

val jacksonVersion = "2.20.0"

libraryDependencies ++= Seq(
  "com.fasterxml.jackson.datatype" % "jackson-datatype-jsr310" % jacksonVersion,
  "com.fasterxml.jackson.module" %% "jackson-module-scala" % jacksonVersion,
  "com.github.pjfanning" %% "jackson-module-scala-duration" % jacksonVersion
)

Jackson 3 example:

val jacksonVersion = "3.0.0"

libraryDependencies ++= Seq(
  "tools.jackson.datatype" % "jackson-datatype-jsr310" % jacksonVersion,
  "tools.jackson.module" %% "jackson-module-scala" % jacksonVersion,
  "com.github.pjfanning" %% "jackson-module-scala-duration" % jacksonVersion
)

// Jackson 2 users should use `com.fasterxml.jackson` instead of `tools.jackson` in imports below
import tools.jackson.databind.SerializationFeature
import tools.jackson.module.scala.DefaultScalaModule
import com.github.pjfanning.scala.duration.DurationModule

val mapper = JsonMapper.builder()
    //.addModule(new com.fasterxml.jackson.datatype.jsr310.JavaTimeModule) -- Jackson 2 only
    .addModule(DefaultScalaModule)
    .addModule(DurationModule)
    .disable(SerializationFeature.WRITE_DURATIONS_AS_TIMESTAMPS)
    .build()