java - @JsonSerialize 和 @JsonDeserialize 包含在注释中时不起作用

Question

我正在尝试创建一个自定义注释，以便在注释给定属性时始终对其进行标记，因此我具有以下结构:

@JsonComponent
public class TokenSerializer {

    @JsonSerialize(using = IdToTokenSerializer.class) // This does not work 
    @JsonDeserialize(using = TokenToIdDeserializer.class) // This does not work 
    @Retention(RetentionPolicy.RUNTIME)
    public static @interface TokenizedId {
        Class<?> value();
    }

    public static class IdToTokenSerializer extends JsonSerializer<Long> implements ContextualSerializer {
        ...
    }

    public static class TokenToIdDeserializer extends JsonDeserializer<Long> implements ContextualDeserializer {
        ...
    }
}

为什么我要这样使用？因为@TokenizedId将提供一个类，序列化器/反序列化器将有条件地考虑该类来执行某些操作。该值使用 ContextualDeserializer 配置，从 @TokenizedId 获取类。

问题是，当我像这样注释时，序列化器和反序列化器都不起作用:

@TokenizedId(MyClass.class)
private Long id;

但是当我像这样使用时它们就起作用了(从@TokenizedId中删除@JsonSerialize和@JsonDeserialize):

@JsonSerialize(using = IdToTokenSerializer.class)
@JsonDeserialize(using = TokenToIdDeserializer.class)
@TokenizedId(MyClass.class)
private Long id;

我个人不喜欢这种方法，因为开发人员在想要标记某些 id 时需要始终记住使用这三个注释，而且我希望 @TokenizedId 始终相关到这些序列化器。

有没有办法让序列化器/反序列化器在另一个注释上进行注释时工作？

Answer 1

我能够使注释按照我想要的方式工作，在 Jackson 库上寻找一些线索，我找到了 @JacksonAnnotationsInside 注释:

/**
 * Meta-annotation (annotations used on other annotations)
 * used for indicating that instead of using target annotation
 * (annotation annotated with this annotation),
 * Jackson should use meta-annotations it has.
 * This can be useful in creating "combo-annotations" by having
 * a container annotation, which needs to be annotated with this
 * annotation as well as all annotations it 'contains'.
 * 
 * @since 2.0
 */
@Target({ElementType.ANNOTATION_TYPE})
@Retention(RetentionPolicy.RUNTIME)
@JacksonAnnotation
public @interface JacksonAnnotationsInside
{

}

在我的注释中包含此内容解决了问题:

@JacksonAnnotationsInside
@JsonSerialize(using = IdToTokenSerializer.class) 
@JsonDeserialize(using = TokenToIdDeserializer.class)
@Retention(RetentionPolicy.RUNTIME)
public static @interface TokenizedId {
    Class<?> value();
}