If you are new to the Scala-Circe library and you want to know how to decode/encode JSON, follow the method below. Your Classes Assume your application has a nested class named Person which has a member named of class . address Address case class Address(doorNo: Int, street: String, city: String, zipCode: String) case class Person(name: String, age: Int, address: Address) Your Task You need to encode objects and decode text using Circe and use them following some business logic. What to do? I will give you a simple straightforward approach that will work for 95% of your use cases. Add implicit codec in companion objects for your case classes. Add encode and decode method in the companion object. import io.circe._, io.circe.generic.semiauto._, io.circe.syntax._ case class Address(doorNo: Int, street: String, city: String, zipCode: String) object Address { implicit val codec = deriveCodec[Address] } case class Person(name: String, age: Int, address: Address) object Person { implicit val codec = deriveCodec[Person] def encode(person: Person): String = { person.asJson.toString } def decode(jsonString: String): Person = { parser.decode[Person](jsonString).toOption.get } } That’s it. You can now use the and methods. Person.encode Person.decode The sample app is below. import io.circe._, io.circe.generic.semiauto._, io.circe.syntax._ val johnDoe = Person("John Doe", 24, Address(5, "Times Square Street", "New York", "12345")) println(Person.encode(johnDoe)) val encodedText = """ { "name" : "Fin", "age" : 21, "address" : { "doorNo" : 7, "street" : "Staten Island", "city" : "New York", "zipCode" : "23456" } } """ val decodedJohnDoe = Person.decode(encodedText) println(decodedJohnDoe) If you want to access the runnable version of this code, along with imports and library version, use scastie link. First published here
