Stéphane Piette Stéphane Piette - 7 months ago 18
Java Question

GSON - Custom serializer in specific case

I have this schema :

public class Student {
public String name;
public School school;
}

public class School {
public int id;
public String name;
}
public class Data {
public ArrayList<Student> students;
public ArrayList<School> schools;
}


I would like to serialize the Data object with Gson, and get something like :

{ "students": [{
"name":"name1",
"school": "1" //the id of the scool, not its entire Json
}],
"school": [{ //the entire JSON
"id" : "1",
"name": "schoolName"
}]
}


To make that, I must use custom serializer for the student part, so that Gson only print the id of the School. But for the School, I have to have nomal serializer.

How can I do everything with only one Gson object ?

Answer

You can write a custom serializer something like this:

public class StudentAdapter implements JsonSerializer<Student> {

 @Override
 public JsonElement serialize(Student src, Type typeOfSrc,
            JsonSerializationContext context)
    {

        JsonObject obj = new JsonObject();
        obj.addProperty("name", src.name);
        obj.addProperty("school", src.school.id);

        return obj;
    }

}