CODEWITHSUNDEEP
jsonparsingscalalift-json
CruncherBigData
CruncherBigData

Reputation: 1122

json-lift extract method not accessable

I am using json-lift that is compatible with scala 2.10 from lift-json but I do not seem to have access to the extract method. like this example :

import net.liftweb.json._
object testobject {

case class process(process_id:Int,job_id:Int ,command:String, exception:String)

def main(args: Array[String]) {
val json = parse("""
    { 
        "process_id": "2",
        "job_id": "540",
        "command": "update",
        "exception": "0"
    }
    """)

    json.extract[process] // produces an error


 }

}

now the class has dynamic parsing , for example the following does not produce any error (sweet):

json.process_id // will produce JString(2)

my two questions are :

  1. How can I map a json object to my case class
  2. How to convert JString to a regular string.

Update: the good people at lift have created an upgrade for scala 2.10.0 ... so you can just downloaded from their. No need for any work around. 

import net.liftweb.json._
object testobject {

case class process(process_id:Int,job_id:Int ,command:String, exception:String)

def main(args: Array[String]) {
val json = parse("""
    { 
        "process_id": "2",
        "job_id": "540",
        "command": "update",
        "exception": "0"
    }
    """)

    val p = json.extract[process] // maps the json object to the process case class
    println(p.job_id) // will print 540



 }

}

Upvotes: 1

Views: 176

Answers (2)

Luther Blissett
Luther Blissett

Reputation: 238

I show you my method to get the proper String, hope helps you:

Suppose a list of tuples with x and y values 

val dataSet:List[(Int,Int)] = new List((0,1),(1,3),(2,6))

I make my JObject (net.liftweb.json.JsonAST.JObject):

val jsonTmp:JObject = ("x" -> dataSet.map(k => k._1)) ~ ("y" -> dataSet.map(k => k._2)))

then I get my String like this:

val jsonString:String = compact(render(jsonTmp))

compact(d:Document):String & render(value:JValue):Document are from json package.

And this is the resulting String (triple quotes are just for code formatting):

"""  {"x":[0,1,2],"y":[1,3,6]}  """

Upvotes: 1

CruncherBigData
CruncherBigData

Reputation: 1122

I got it: 

val process_id = json.process_id match { case JString(s) => s.toInt }

Upvotes: 0

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