使用Circe展平嵌套的JSON对象

import io.circe._
import io.circe.parser._
import io.circe.syntax._

val nestedJson = """
{
  "name": "John",
  "age": 30,
  "address": {
    "street": "123 Main St",
    "city": "New York",
    "state": "NY"
  }
}
"""

val json = parse(nestedJson).getOrElse(Json.Null)

def flattenJson(json: Json, prefix: String = ""): Map[String, String] = {
  json.fold(
    Map.empty[String, String],
    bool => Map(prefix -> bool.toString),
    num => Map(prefix -> num.toString),
    str => Map(prefix -> str),
    arr => arr.toList.zipWithIndex.flatMap {
      case (value, index) => flattenJson(value, s"$prefix[$index]")
    }.toMap,
    obj => obj.toMap.flatMap {
      case (key, value) => flattenJson(value, if (prefix.isEmpty) key else s"$prefix.$key")
    }
  )
}

val flattenedJson = flattenJson(json)
flattenedJson.foreach { case (key, value) =>
  println(s"$key: $value")
}