JSON を scala で解析しようとしていますが、うまくいきません。これが私のJSON構造です:
{
"data" : "test",
"field" : "test",
"listObj" : [{
"data" : "testInner1",
"field" : "testInner1"
} , {
"data" : "testInner2",
"field" : "testInner2"
}],
"obj" : {
"data" : "testInner1",
"field" : "testInner1"
}
}
リフトを使用して解析しています。これが私のコードです:
import net.liftweb.json._
implicit val formats = DefaultFormats
case class MyJson(data: String, field: String, obj: MyJson, listObj: List[MyJson])
val json = parse("""
{
"data" : "test",
"field" : "test",
"listObj" : [{
"data" : "testInner1",
"field" : "testInner1"
} , {
"data" : "testInner2",
"field" : "testInner2"
}],
"obj" : {
"data" : "testInner1",
"field" : "testInner1"
}
}""")
println(json.extract[Query])
私は次の例外を神にしました:
Caused by: net.liftweb.json.MappingException: No usable value for operation
Did not find value which can be converted into java.lang.String
at net.liftweb.json.Meta$.fail(Meta.scala:191)
at net.liftweb.json.Extraction$.mkValue$1(Extraction.scala:357)
at net.liftweb.json.Extraction$.net$liftweb$json$Extraction$$build$1(Extraction.scala:317)
at net.liftweb.json.Extraction$$anonfun$13.apply(Extraction.scala:253)
at net.liftweb.json.Extraction$$anonfun$13.apply(Extraction.scala:253)
at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)
at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)
at scala.collection.immutable.List.foreach(List.scala:318)
at scala.collection.TraversableLike$class.map(TraversableLike.scala:244)
at scala.collection.AbstractTraversable.map(Traversable.scala:105)
at net.liftweb.json.Extraction$.instantiate$1(Extraction.scala:253)
at net.liftweb.json.Extraction$.newInstance$1(Extraction.scala:286)
at net.liftweb.json.Extraction$.net$liftweb$json$Extraction$$build$1(Extraction.scala:315)
at net.liftweb.json.Extraction$.mkValue$1(Extraction.scala:351)
... 34 more
Caused by: net.liftweb.json.MappingException: Did not find value which can be converted into java.lang.String
at net.liftweb.json.Meta$.fail(Meta.scala:191)
at net.liftweb.json.Extraction$.convert(Extraction.scala:403)
at net.liftweb.json.Extraction$.net$liftweb$json$Extraction$$build$1(Extraction.scala:314)
at net.liftweb.json.Extraction$.mkValue$1(Extraction.scala:351)
... 46 more
json4s を使用してみましたが、ケース クラスに解析することができました。JSON から obj と objList を削除すると、うまく機能します。
この種の構造を解析して Scala で読み取る方法を教えてください。