Spring Boot中如何通过Jackson注解仅序列化指定字段

方案一：使用@JsonInclude+自定义PropertyFilter #

这是最快捷的原生方案，不用自定义注解，直接利用Jackson的Filter机制实现：

1. 编写自定义Filter类，只保留指定字段：

public class IncludeOnlyFilter extends SimpleBeanPropertyFilter {
    private final Set<String> allowedFields;

    public IncludeOnlyFilter(Set<String> allowedFields) {
        this.allowedFields = allowedFields;
    }

    @Override
    protected boolean include(BeanPropertyWriter writer) {
        return allowedFields.contains(writer.getName());
    }

    @Override
    protected boolean include(PropertyWriter writer) {
        return allowedFields.contains(writer.getName());
    }
}

2. 在DTO类上标注@JsonFilter指定过滤器名称：

@JsonFilter("includeOnlyFilter")
public class ClassToSerializeDTO {
    Object field1;
    Object field2;
    // ...
    Object field25;
}

3. 配置Jackson的ObjectMapper（Spring Boot可全局配置）：

@Configuration
public class JacksonConfig {
    @Bean
    public ObjectMapper objectMapper() {
        ObjectMapper mapper = new ObjectMapper();
        FilterProvider filters = new SimpleFilterProvider()
                .addFilter("includeOnlyFilter", new IncludeOnlyFilter(Set.of("field2")));
        mapper.setFilterProvider(filters);
        return mapper;
    }
}

方案二：自定义@JsonIgnoreAllExcept注解 #

如果想要完全贴合你设想的注解形式，可以自定义注解并扩展Jackson的注解解析逻辑：

1. 定义自定义注解：

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface JsonIgnoreAllExcept {
    String[] value();
}

2. 编写自定义注解解析器，将注解规则转换为Jackson的忽略逻辑：

public class IgnoreAllExceptIntrospector extends JacksonAnnotationIntrospector {
    @Override
    public Boolean hasIgnoreMarker(AnnotatedMember m) {
        Boolean parentResult = super.hasIgnoreMarker(m);
        if (parentResult != null) {
            return parentResult;
        }

        JsonIgnoreAllExcept annotation = m.getDeclaringClass().getAnnotation(JsonIgnoreAllExcept.class);
        if (annotation != null) {
            Set<String> allowedFields = Set.of(annotation.value());
            return !allowedFields.contains(m.getName());
        }

        return null;
    }
}

3. 配置Jackson使用自定义解析器：

@Configuration
public class JacksonConfig {
    @Bean
    public ObjectMapper objectMapper() {
        ObjectMapper mapper = new ObjectMapper();
        mapper.setAnnotationIntrospector(new IgnoreAllExceptIntrospector());
        return mapper;
    }
}

4. 在DTO上直接使用自定义注解：

@JsonIgnoreAllExcept(value = {"field2"})
public class ClassToSerializeDTO {
    Object field1;
    Object field2;
    // ...
    Object field25;
}

方案三：@JsonProperty配合访问策略（小字段场景） #

如果DTO字段数量不多，也可以直接通过@JsonProperty的访问权限控制实现：

public class ClassToSerializeDTO {
    // 仅允许反序列化，不参与序列化
    @JsonProperty(access = JsonProperty.Access.WRITE_ONLY)
    Object field1;

    // 正常参与序列化和反序列化
    Object field2;

    // 其他字段同理设置为WRITE_ONLY
    @JsonProperty(access = JsonProperty.Access.WRITE_ONLY)
    Object field3;
    // ...
    @JsonProperty(access = JsonProperty.Access.WRITE_ONLY)
    Object field25;
}

内容的提问来源于stack exchange，提问作者smeds