버전 지원을 활성화하기 위해 Java에서 Gson을 구성하는 방법은 무엇입니까?

public GsonBuilder setVersion(double ignoreVersionsAfter)

import com.google.gson.*;
import com.google.gson.annotations.*;
public class VersionSupportTest {
   public static void main(String[] args) {
      Person person = new Person();
      person.firstName = "Raja";
      person.lastName = "Ramesh";
      Gson gson1 = new GsonBuilder().setVersion(1.0).setPrettyPrinting().create();
      System.out.println("Version 1.0:");
      System.out.println(gson1.toJson(person));
      Gson gson2 = new GsonBuilder().setVersion(2.0).setPrettyPrinting().create();
      System.out.println("Version 2.0:");
      System.out.println(gson2.toJson(person));
   }
}
// Person class
class Person {
   @Since(1.0)
   public String firstName;
   @Since(2.0)<strong>
</strong>   public String lastName;
}

Version 1.0:
{
 "firstName": "Raja"
}
Version 2.0:
{
 "firstName": "Raja",
 "lastName": "Ramesh"
}