genson java json API cookbook as unit test cases. / published by https://github.com/dacr/code-examples-manager #398573c4-cdea-4db3-86f2-308f60d68cef/e7eb9b8e0610a87ce7ee1825a522799766a1266c

json-genson.sc

// summary : genson java json API cookbook as unit test cases.
// keywords : scala, scalatest, genson, json, @testable
// publish : gist
// authors : David Crosson
// license : Apache NON-AI License Version 2.0 (https://raw.githubusercontent.com/non-ai-licenses/non-ai-licenses/main/NON-AI-APACHE2)
// id : 398573c4-cdea-4db3-86f2-308f60d68cef
// created-on : 2019-09-27T15:07:21Z
// managed-by : https://github.com/dacr/code-examples-manager
// run-with : scala-cli $file

// ---------------------
//> using scala  "3.1.1"
//> using dep "org.scalatest::scalatest:3.2.10"
//> using dep "com.owlike:genson:1.6"
//// using lib "com.owlike::genson-scala:1.6" // not available yet for scala 2.13
// ---------------------

import org.scalatest.*,  flatspec.*,  matchers.*
import com.owlike.genson.*
import java.text.SimpleDateFormat
import scala.jdk.CollectionConverters._

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

object JsonGensonCookBook extends AnyFlatSpec with should.Matchers {
  override def suiteName = "JsonGensonCookBook"

  "genson" should "deserialize json array strings as java/scala array" in {
    val genson = new Genson()
    val decoded = genson.deserialize("""[1,2,3]""", classOf[Array[Int]])
    decoded shouldBe Array(1,2,3)
  }

  it should "deserialize string as string" in {
    val genson = new Genson()
    val decoded = genson.deserialize(""" "truc" """, classOf[String])
    decoded shouldBe "truc"
  }

  it should "deserialize json array strings as java list" in {
    val genson = new Genson()
    val decoded = genson.deserialize("""[1,2,3]""", classOf[java.util.ArrayList[Int]])
    val expected = new java.util.ArrayList[Int]()
    expected.addAll(List(1,2,3).asJava)
    decoded.asScala shouldBe expected.asScala
  }

  it should "be possible to add meta class information in serialized json" in {
    val genson =
      new GensonBuilder()
        .useClassMetadata(true)
        .setSkipNull(true)
        .useRuntimeType(true)
        .useConstructorWithArguments(true) // Take care, with true you may encounter IllegalArgumentException within asm.ClassReader
        .create()
    val point = new java.awt.Point(42, 24)
    val encoded = genson.serialize(point)
    encoded shouldBe """{"x":42, "y":24}"""
  }

  // This is a java API, friendly suitable for scala...
  it should "deserialize scala case classes works fine !" in {
    val dateFormatPattern = "yyyy-MM-dd'T'HH:mm:ss'Z'"
    val builder =
      new GensonBuilder()
        .useDateFormat(new SimpleDateFormat(dateFormatPattern))
        .setSkipNull(true)
        .useIndentation(true)
        .useConstructorWithArguments(true) // Take care, with true you may encounter IllegalArgumentException within asm.ClassReader
        .useRuntimeType(true)
        .useDateAsTimestamp(true)
        //.withBundle(ScalaBundle().useOnlyConstructorFields(false)) // requires the genson-scala dependency but not avail yet for scala 2.13
    val genson = builder.create()
    val decoded = genson.deserialize("""{"age":42, "name":"John"}""", classOf[Person])
    decoded shouldBe Person(42, "John")
  }

}

JsonGensonCookBook.execute()