Revision history [back]

You can use the @JsonInclude annotation on the fields that you want to include and set its value to NONNULL or NONEMPTY. This will ensure that the fields are included in the serialized output only if they are not null or empty.

For example, consider a class with two fields:

public class MyClass {

  private String name;

  @JsonInclude(JsonInclude.Include.NON_NULL)
  private String id;

  // getters and setters
}

In this case, the 'id' field will be included in the serialized output only if it is not null. The 'name' field will be ignored by default because it is not annotated with @JsonInclude.

Alternatively, you can use a custom serializer to selectively ignore fields based on your criteria.

public class MyClassSerializer extends JsonSerializer<MyClass> {

    @Override
    public void serialize(MyClass myClass, JsonGenerator jsonGenerator, SerializerProvider provider) throws IOException {

        jsonGenerator.writeStartObject();

        jsonGenerator.writeStringField("name", myClass.getName());

        if(myClass.getId()!=null && !myClass.getId().isEmpty()) {
            // serialize id only if it is not null or empty
            jsonGenerator.writeStringField("id", myClass.getId());
        }

        // write other fields

        jsonGenerator.writeEndObject();
    }
}

Then, annotate your class with @JsonSerialize using the custom serializer:

@JsonSerialize(using = MyClassSerializer.class)
public class MyClass {

  private String name;

  private String id;

  // getters and setters
}

This will ensure that only the fields that you want to include are serialized, and others are ignored.