Question

如果我有一个类层次结构，如A - ＆gt; B，其中A是基类，如何在Jackson序列化期间指定仅包含基类中的字段并从子类中排除所有内容？我序列化的是B（子类）。

感谢帮助!!

Answer 1

您可以使用Jackson JSON views中提及的this similar question。

此外，您可以编写an annotation introspector或Jackson JSON filter来排除子类中的所有内容。

我编写了一个示例，演示如何从具有特殊注释的层次结构中的类型中排除所有属性。

public class JacksonExcludeFromSubclass {

    @Retention(RetentionPolicy.RUNTIME)
    public static @interface IgnoreTypeProperties {};

    public static class SuperThing {
        public final String superField;

        public SuperThing(String superField) {
            this.superField = superField;
        }
    }

    @JsonFilter("filter")
    @IgnoreTypeProperties
    public static class Thing extends SuperThing {
        public final String thingField;

        public Thing(String superField, String thingField) {
            super(superField);
            this.thingField = thingField;
        }
    }

    public static class ExcludeFromSuperClass extends SimpleBeanPropertyFilter {

        @Override
        protected boolean include(BeanPropertyWriter writer) {
            return true;
        }

        @Override
        protected boolean include(PropertyWriter writer) {
            if (writer instanceof BeanPropertyWriter) {
                AnnotatedMember member = ((BeanPropertyWriter) writer).getMember();
                return member.getDeclaringClass().getAnnotation(IgnoreTypeProperties.class) == null;
            }
            return true;
        }
    }

    public static void main(String[] args) throws JsonProcessingException {
        Thing t = new Thing("super", "thing");
        ObjectMapper mapper = new ObjectMapper();
        mapper.setFilters(new SimpleFilterProvider().addFilter("filter", new ExcludeFromSuperClass()));
        System.out.println(mapper.writerWithDefaultPrettyPrinter().writeValueAsString(t));
    }

输出：

{
  "superField" : "super"
}

在jackson序列化期间从层次结构中选择特定的类类型

1 个答案: