JSON in Scala – an exercise in pattern matching

There are several libraries for manipulating JSON in Scala. We prefer json4s, but if you are a die-hard fan of another JSON library, you should be able to readily adapt the examples in this chapter. Let's create a build.sbt file with a dependency on json4s:

// build.sbt
scalaVersion := "2.11.7"

libraryDependencies += "org.json4s" %% "json4s-native" % "3.2.11"

We can then import json4s into an SBT console session with:

scala> import org.json4s._
import org.json4s._

scala> import org.json4s.native.JsonMethods._
import org.json4s.native.JsonMethods._

Let's use json4s to parse the response to our GitHub API query:

scala> val jsonResponse = parse(response)
jsonResponse: org.json4s.JValue = JObject(List((login,JString(odersky)),(id,JInt(795990)),...

The parse method takes a string (that contains well-formatted JSON) and converts it to a JValue, a supertype for all json4s objects. The runtime type of the response to this particular query...