包含在注释中时，@ JsonSerialize和@JsonDeserialize无法正常工作 [英] @JsonSerialize and @JsonDeserialize not working when included in an annotation

问题描述

我试图创建一个自定义批注，以始终在给定属性添加注记的情况下将其标记化，因此我具有以下结构:

I am trying to create a custom annotation to tokenize a given property always when it is annotated with, so I have the following structure:

@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 {
        ...
    }
}

我为什么要那样使用?因为@TokenizedId将提供一个类，有条件地将在序列化器/反序列化器上考虑该类以执行某项操作.使用ContextualDeserializer配置此值，然后从@TokenizedId获取类.

Why am I using like that? Because the @TokenizedId will provide a class, which conditionally will be considered on the serializer/deserializer to do something. This value is configured using the ContextualDeserializer, fetching the class from @TokenizedId.

问题是，当我这样注释时，序列化程序和反序列化程序都无法工作:

The issue is, both serializer and deserializer do not work when I annotate just like this:

@TokenizedId(MyClass.class)
private Long id;

但是当我这样使用它们时(从@TokenizedId中删除@JsonSerialize和@JsonDeserialize)，它们会起作用:

But they work when I use like this (removing the @JsonSerialize and @JsonDeserialize from @TokenizedId):

@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对某些ID进行标记时，必须始终记住使用这三个注释，而且我希望@TokenizedId始终与这些序列化程序相关.

Personally I did not like this approach, since developers will need to always remember to use these three annotations when they would like to tokenize some id, and also I would like the @TokenizedId always be related to these serializers.

在另一个注释上注释时，有没有办法使序列化器/反序列化器正常工作?

Is there a way to make the serializer/deserializer work when annotated on another annotation?

推荐答案

我能够按照我想要的方式使注释起作用，在查看Jackson图书馆的一些线索后，我发现了@JacksonAnnotationsInside注释:

I was able to make the annotation works the way I wanted, looking after some clue on the Jackson lib, I found the @JacksonAnnotationsInside annotation:

/**
 * 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可解决此问题:

Including this on my annotation solved the issue:

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

这篇关于包含在注释中时，@ JsonSerialize和@JsonDeserialize无法正常工作的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！