从application.conf中检索对象列表

Question

I have the following entry in Play for Scala application.conf :

    jobs = [
       {number: 0, dir: "/dir1", name: "General" },
       {number: 1, dir: "/dir2", name: "Customers" }
    ] 

I want to retrieve this list of objects in a Scala program:

    val conf = ConfigFactory.load
    val jobs = conf.getAnyRefList("jobs").asScala 
    println(jobs)

this prints

Buffer({number=0, name=General, dir=/dir1}, {number=1, name=Customers, dir=/dir2})

But how to convert the result to actual Scala objects?

Answer 1

Try this one:

case class Job(number: Int, dir: String, name: String)

object Job {
implicit val configLoader: ConfigLoader[List[Job]] = ConfigLoader(_.getConfigList).map(
    _.asScala.toList.map(config =>
      Job(
        config.getInt("number"),
        config.getString("dir"),
        config.getString("name")
      )
    )
  )
}

Then from Confugutation DI Configuration.get[List[Job]]("jobs")

Answer 2

Here is a Config object which will extract data from a config file into a type that you specify.

Usage:

case class Job(number: Int, dir: String, name: String)

val jobs = Config[List[Job]]("jobs")

Code:

import com.typesafe.config._
import org.json4s._
import org.json4s.jackson.JsonMethods._

object Config {
  private val conf = ConfigFactory.load()
  private val jData = parse(conf.root.render(ConfigRenderOptions.concise))

  def apply[T](name: String)(implicit formats: Formats = DefaultFormats, mf: Manifest[T]): T =
    Extraction.extract(jData \\ name)(formats, mf)
}

This will throw an exception if the particular config object does not exist or does not match the format of T .