这将适用于Spring boot 2.0.3+和Jackson 2.0+

import com.fasterxml.jackson.annotation.JsonInclude;

@JsonInclude(JsonInclude.Include.NON_NULL)
public class ApiDTO
{
    // your class variable and 
    // methods
}

对于Jackson>1.9.11和<2.x，请使用@JsonSerialize注释来实现：

@JsonSerialize（include=JsonSerialize.Inclusion.NON_NULL）

如果您想将此规则添加到Jackson 2.6+中的所有模型，请使用：

mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);

此外，当使用MapmyVariable（如文档中所述）来命名null时，您必须更改方法：

From documentation:
com.fasterxml.jackson.annotation.JsonInclude

@JacksonAnnotation
@Target(value={ANNOTATION_TYPE, FIELD, METHOD, PARAMETER, TYPE})
@Retention(value=RUNTIME)
Annotation used to indicate when value of the annotated property (when used for a field, method or constructor parameter), or all properties of the annotated class, is to be serialized. Without annotation property values are always included, but by using this annotation one can specify simple exclusion rules to reduce amount of properties to write out.

*Note that the main inclusion criteria (one annotated with value) is checked on Java object level, for the annotated type, and NOT on JSON output -- so even with Include.NON_NULL it is possible that JSON null values are output, if object reference in question is not `null`. An example is java.util.concurrent.atomic.AtomicReference instance constructed to reference null value: such a value would be serialized as JSON null, and not filtered out.

To base inclusion on value of contained value(s), you will typically also need to specify content() annotation; for example, specifying only value as Include.NON_EMPTY for a {link java.util.Map} would exclude Maps with no values, but would include Maps with `null` values. To exclude Map with only `null` value, you would use both annotations like so:
public class Bean {
   @JsonInclude(value=Include.NON_EMPTY, content=Include.NON_NULL)
   public Map<String,String> entries;
}

Similarly you could Maps that only contain "empty" elements, or "non-default" values (see Include.NON_EMPTY and Include.NON_DEFAULT for more details).
In addition to `Map`s, `content` concept is also supported for referential types (like java.util.concurrent.atomic.AtomicReference). Note that `content` is NOT currently (as of Jackson 2.9) supported for arrays or java.util.Collections, but supported may be added in future versions.
Since:
2.0

如果在Spring Boot中，您可以直接通过属性文件自定义jackson ObjectMapper。

示例application.yml：

spring:
  jackson:
    default-property-inclusion: non_null # only include props if non-null

可能的值包括：

always|non_null|non_absent|non_default|non_empty

更多信息：https://docs.spring.io/spring-boot/docs/current/reference/html/howto-spring-mvc.html#howto-自定义jackson对象映射器

您可以使用以下映射器配置：

mapper.getSerializationConfig().setSerializationInclusion(Inclusion.NON_NULL);

从2.5开始，您可以使用：

mapper.setSerializationInclusion(Include.NON_NULL);