@jsonproperty以相同的属性名称序列化不同的pojo元素

Question

I have a simple pojo

public class C {
   public String f1;
   public Integer f2;
}

At runtime I am sure at most one of the fields is not null (ie if f1 is "hello" , I'm sure f2 is null , and vice versa)

I would like to serialize the object using always the same name; for example, with

C c1 = new C();
c1.f1 = "hello"
C c2 = new C();
c2.f2 = Integer.valueOf(99)

I would like to have c1 serialized as {"samekey":"hello"} and c2 as {"samekey":99} .

I know I can use @JsonProperty to set the serialized name, but I cannot set the same name to both the fields.

Is there a way to say that?

Answer 1

Here is the CustomSerializer, checks if f2 value not null then f2 value is copied to f1 and making f2=null.And excluding nulls in the model so always you will get one key&value as other one will be null.

public class CustomSerializer extends JsonSerializer<C> {

@Override
public void serialize(final C c, final JsonGenerator gen, final SerializerProvider serializers) throws IOException, JsonProcessingException {
    if(c.getF2() != null)  // considering always you need f1 key && value
    {
        c.setF1(c.getF2().toString());
        c.setF2(null);
    }
}

}

Annotate serializer & notnull in model as

@JsonSerialize(using = CustomSerializer.class)
@JsonInclude(JsonInclude.Include.NON_NULL)
public class C {
   private String f1;
   private Integer f2;

   //getters & setters
}

Hope this is what you are expecting.