scala playframework json implicit case class conversion

问题

I am developing my first Play 2.1 application in Scala. The task I am trying to accomplish is to parse json into 3 different case classes. The problem is - I do not know where to declare all case classes. Each class in it's own file or all in one file. Here is what I've done (it doesn't work, case values are not visible in controller object):

File LoginBase.scala

package models


abstract class LoginBase 

case class Login(email: String, password: String) extends         LoginBase
case class RestoreLogin(email: String, captchaID: String,         captchaAnswer: String) extends LoginBase
case class RegisterLogin(email: String, password: String,         captchaID: String, captchaAnswer: String) extends LoginBase

File

package controllers

import play.api._
import play.api.mvc._
import play.api.data._
import play.api.data.Forms._
import play.api.Play.current
import play.api.cache.Cache
import play.api.libs.json._
import play.api.mvc._
import play.api.libs.functional.syntax._

import nl.captcha.Captcha
import nl.captcha.Captcha._
import nl.captcha.gimpy.FishEyeGimpyRenderer
import nl.captcha.text.renderer.ColoredEdgesWordRenderer
import nl.captcha.text.renderer.DefaultWordRenderer
import nl.captcha.gimpy.DropShadowGimpyRenderer

import java.io.ByteArrayOutputStream
import javax.imageio.ImageIO
import java.util.UUID

import play.api.libs.functional.syntax._
import models.LoginBase

object LoginActions extends Controller {


    implicit val loginReads = (
      (__ \ "email").read[String] and
      (__ \ "password").read[String]
    )(Login.apply _) 


    implicit val restoreLoginReads = (
      (__ \ "email").read[String] and
      (__ \ "captchaID").read[String] and
      (__ \ "captchaAnswer").read[String]
    )(RestoreLogin) 

    implicit val registerLoginReads = (
      (__ \ "email").read[String] and
      (__ \ "password").read[String] and
      (__ \ "captchaID").read[String] and
      (__ \ "captchaAnswer").read[String]
    )(RegisterLogin) 



    def registerLogin = Action(parse.json){
        /*  To be implementd */
    }

}

If someone can help me with this, I'll appreciate. All I can find is REPL examples, but I am missing some fundamental stuff - where to put all the pieces of code? what is the file structure?

Thanks, Andrei.

回答1:

Having multiple classes and objects inside a single file is considered good form in Scala, as long as the classes are tightly related.

please refer Elements of Scala Style? for more detail answer.

Here is example of converting json to scala case class in restful ws.

enter code here

import play.api.libs.json.{Reads, JsError, Json}
import play.api.libs.json.JsValue

object someController e

xtends Controller{

case class SomeResource(val Id:String, val someType:String, val Serialno:String)

implicit val reads:Reads[SomeResource] = Json.reads[SomeResource]

/**
   * save some object
   */
  def someService = Action(parse.json){request=>
    unmarshalOrderResource(request, (resource: SomeResource) => {
            val someValue = SomeResource(resource.Id,
                            resource.someType,resource.Serialno);
            someservice.save(someValue);
            Created(someValue.Id)
        })
  }


// method
 private def unmarshalOrderResource(request: Request[JsValue],
                                      block: (SomeResource) => Result): Result = {
        request.body.validate[SomeResource].fold(
            valid = block,
            invalid = (e => {
                val error = e.mkString
                Logger.error(error)
                BadRequest(error)
            })
        )
    }

}

回答2:

One of the things that is different between Java and Scala is that Scala requires no specific file/folder structure. The packages don't even have to correspond to folders. Also, you can have multiple classes per file.

Basically, what you have is fine.

The thing that must remain the same is the imports. So, if you're asking why your stuff won't compile, try importing everything in the models package.

import models._

来源：https://stackoverflow.com/questions/16121713/scala-playframework-json-implicit-case-class-conversion

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json

scala

playframework

case

implicit