试试看：

YAMLMapper mapper = new YAMLMapper();
mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
YAMLFactory factory = new YAMLFactory(mapper);
factory.enable(YAMLGenerator.Feature.MINIMIZE_QUOTES);
ObjectMapper mapper = new ObjectMapper(factory);

然后，使用这个类别：

public class Worker {
  private Boolean disable;
  private String name;
  private Long duration;
}

未给定的字段现在应该是null，并且null字段不应该被序列化。您可能需要查看optional types with Jackson以获得更复杂的设置。