Micronaut中@JsonDeserialize注解未按预期生效问题

环境信息 #

• OS: Windows 11
• JDK: corretto-17.0.6
• IDE: IntelliJ IDEA 2022.3.1
• Micronaut版本: 3.7.3

问题场景 #

开发了一个执行基础IO操作的Micronaut应用，DTO类EventBean中的duration字段需要以毫秒为单位处理，而非默认的秒。

POST接口代码如下：

@Post
public EventBean create(@Body EventBean eventBean) {
    return eventBean;
}

发送的JSON请求体：

{
    "from": "2023-03-05T12:26:43.538Z",
    "duration": 600000
}

预期返回与请求体一致，但实际返回：

{
    "from": "2023-03-05T12:26:43.538Z",
    "duration": 600000000
}

EventBean类代码：

@Introspected
public class EventBean {
    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'", timezone = "UTC")
    private final Instant from;

    @JsonSerialize(converter = DurationSerializer.class)
    @JsonDeserialize(converter = DurationDeserializer.class)
    private final Duration duration;

    public EventBean(Instant from, Duration duration) {
        this.from = from;
        this.duration = duration;
    }

    public Instant getFrom() {
        return from;
    }

    public Duration getDuration() {
        return duration;
    }

    public static class DurationSerializer extends StdConverter<Duration, Long> {
        @Override public Long convert(Duration value) {
            return value.toMillis();
        }
    }

    public static class DurationDeserializer extends StdConverter<Long, Duration> {
        @Override public Duration convert(Long value) {
            return Duration.ofMillis(value);
        }
    }
}

核心问题 #

反序列化JSON请求体时，自定义的DurationDeserializer未被调用（DurationSerializer工作正常）。尝试过使用JsonDeserializer<T>类配合@JsonDeserialize注解的using属性，同样无效。

临时解决方法 #

通过Micronaut的@Replaces注解替换Jackson默认的DurationDeserializer：

@Replaces(value = com.fasterxml.jackson.datatype.jsr310.deser.DurationDeserializer.class)
public class DurationDeserializer extends JsonDeserializer<Duration> {
    @Override public Duration deserialize(JsonParser p, DeserializationContext ctxt)
        throws IOException {
        return Duration.ofMillis(p.getLongValue());
    }
}

内容的提问来源于stack exchange，提问作者Tanay Ghirnikar