Scala如何处理(多级)JSON字符串

Scala如何处理(多级)JSON字符串

---

1.JSON.parseFull

• 简单JSON格式

  import scala.util.parsing.json.JSON
  
  val jsonStr = """{"username":"Ricky", "age":"21"}"""
  val jsonValue = JSON.parseFull(jsonStr)
  
  val jsonObj = jsonValue match {
  case Some(map:Map[String, String]) => map
  case _ => println("ERROR jsonStr")
  }
  
  val username = jsonObj.get("username")

• 多级JSON字符串

  import scala.util.parsing.json.JSON
  
  val jsonStr = """{"username":"Ricky", "attribute":{"age":21, "weight": 60}}"""
  val jsonValue = JSON.parseFull(jsonStr)
  
  val jsonObj = jsonValue match {
  case Some(map:Map[String, Any]) => map
  case other => println("Error jsonStr")
  }
  
  // 将attribute转换成Map
  val attrObj = jsonObj.get("attribute").get.asInstanceOf[Map[String, String]]
  
  val age = attrObj.get("age")

2.spary-json

DefaultJsonProtocol

spary-json定义了以下数据类型, 可以根据JSON字符串定义格式

• Byte, Short, Int, Long, Float, Double, Char, Unit, Boolean
• String, Symbol
• BigInt, BigDecimal
• Option, Either, Tuple1 - Tuple7
• List, Array
• immutable.{Map, Iterable, Seq, IndexedSeq, LinearSeq, Set, Vector}
• collection.{Iterable, Seq, IndexedSeq, LinearSeq, Set}

• JsValue

  • 简单JSON格式

  import spray.json._
  import DefaultJsonProtocol._
  
  val jsonStr = """{"username":"Ricky", "age":"21"}"""
  val jsonObj = jsonStr.parseJson.convertTo[Map[String, String]]
  val username = jsonObj.get("username")

  • 多级JSON格式

  import spary.json._
  import DefaultJsonProtocol._
  
  val jsonStr = """{"username":"Ricky", "attribute":{"age":21, "weight": 60}}"""
  
  // 这里的JsValue相当于Scala中的Any
  // 当JSON字符串格式不一定是可以用这种方法
  val jsonObj = jsonStr.parseJson.convertTo[Map[String, JsValue]]
  val attrObj = jsonObj.get("attribute").get.asJsObject().
      convertTo[Map[String,String]]
  
  val username = jsonObj.getOrElse("username", "RickyHuo").toString
  
  println(username)
  // "username"
  // 这里需要注意， JsValue中字符串自带双引号， 之后使用需要手动去除

YourJsonProtocol(自定义协议)

• 简单JSON格式

case class Person(username: String, age:Int)

object MyJsonProtocol extends DefaultJsonProtocol {
    implicit val personFormat = jsonFormat2(Person)
}

import MyJsonProtocol._
import spray.json._

val jsonStr = """{"username":"Ricky", "age":21}"""
val jsonObj = jsonStr.parseJson.convertTo[Person]

val username = jsonObj.username

• 多级JSON格式
  待验证

case class Person(username: String, attribute:Attribute)
case class Attribute(age: Int, weight: Int)

object MyJsonProtocol extends DefaultJsonProtocol {
    implicit val personFormat = jsonFormat2(Person)
}

import MyJsonProtocol._
import spray.json._

val jsonStr = """{"username":"Ricky", "attribute": {"age":12, "weight":60}}"""
val jsonObj = jsonStr.parseJson.convertTo[Person]

val username = jsonObj.username

3.Reference

spary-json