java - 如何使用 Jackson 序列化注释

Question

我有一个简单的注释类:

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.TYPE)
public @interface WebService { // with methods}

还有一个pojo

class Pojo {
    Webservice webservice;
}

每当我尝试序列化 Pojo 时，除了 Webservice 字段之外的所有字段都会被序列化。

我对反序列化不感兴趣，只对序列化感兴趣。

这是 jackson 的限制吗？

Answer 1

问得好。如果您在注释类型方法上放置 @JsonProperty 注释，则序列化工作正常。这是一个例子:

@JacksonAnnotationSerialization.MyAnnotation(a = "abc", b = 123)
public class JacksonAnnotationSerialization {

    @Retention(RetentionPolicy.RUNTIME)
    @interface MyAnnotation {
        @JsonProperty
        String a();
        @JsonProperty
        int b();
    }

    static class Thing {
        public final String field;
        public final MyAnnotation myAnnotation;

        Thing(final String field, final MyAnnotation myAnnotation) {
            this.field = field;
            this.myAnnotation = myAnnotation;
        }
    }

    public static void main(String[] args) throws JsonProcessingException {
        final ObjectMapper objectMapper = new ObjectMapper();
        final MyAnnotation annotation
                = JacksonAnnotationSerialization.class.getAnnotation(MyAnnotation.class);
        final Thing thing = new Thing("value", annotation);
        System.out.println(objectMapper.writeValueAsString(thing));
    }
}

输出:

{"field":"value","myAnnotation":{"a":"abc","b":123}}