issues with serialize LocalDate(Time)

[Chris C]

I am using Java 8 and Jackon 2.9.6. I have these jars in my classpath :

j

ackson-annotations-2.9.6.jar
jackson-core-2.9.6.jar
jackson-databind-2.9.6.jar
jackson-datatype-jdk8-2.9.6.jar
jackson-datatype-jsr310-2.9.6.jar

I have the following classes (trimmed for simplicity) :

@JsonTypeInfo(use = JsonTypeInfo.Id.CLASS, property = "@class")
public abstract class ContractData {

    public String toJSON() {
        try {
            ObjectMapper mapper = new ObjectMapper();
            mapper.registerModule(new Jdk8Module());
            mapper.registerModule(new JavaTimeModule());

            return new ObjectMapper().writeValueAsString(this);
        }
        catch (JsonProcessingException ex) {
            throw new IllegalStateException("unable to write data as json", ex);
        }
    }

    public static ContractData fromJSON(String json) {
        try {
            ObjectMapper mapper = new ObjectMapper();
            mapper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
            mapper.registerModule(new Jdk8Module());
            mapper.registerModule(new JavaTimeModule());

            return mapper.readValue(json, ContractData.class);
        }
        catch (IOException ex) {
            throw new IllegalArgumentException("unable to convert json", ex);
        }
    }
}

public final class RegistrationContractData
extends ContractData
implements Serializable {

    public static final long serialVersionUID = 1L;

    private LocalDateTime created;

    public RegistrationContractData() { }

    public LocalDateTime getCreated() {
        return this.created;
    }

    public void setCreated(LocalDateTime created) {
        this.created = created;
    }
}

If I serialize an instance of RegistrationContractData using the toJSON method, I get this :

"@class":"mypackage.contracts.data.RegistrationContractData","created":{"year":2018,"month":
"JULY","monthValue":7,"dayOfMonth":20,"hour":20,"minute":3,"second":33,"nano":653000000,"dayOfWeek":"FRIDAY","dayOfYear":201,"chronology":{"calendarType":"iso8601","id":"ISO"}}}

When I try and deserialize the string, I get this exception :

Caused by: com.fasterxml.jackson.databind.exc.MismatchedInputException: Expected array or string.
 at [Source: (String)"{"@class":"mypackage.contracts.data.RegistrationContractData","created":{"year":2018,"month":"JULY","monthValue":7,"dayOfMonth":20,"hour":20,"minute":3,"second":33,"nano":653000000,"dayOfWeek":"FRIDAY","dayOfYear":201,"chronology":{"calendarType":"iso8601","id":"ISO"}}}"; line: 1, column: 95] (through reference chain: mypackage.contracts.data.RegistrationContractData["created"])
        at com.fasterxml.jackson.databind.exc.MismatchedInputException.from(MismatchedInputException.java:63) ~[jackson-databind-2.9.6.jar:2.9.6]
        at com.fasterxml.jackson.databind.DeserializationContext.reportInputMismatch(DeserializationContext.java:1342) ~[jackson-databind-2.9.6.jar:2.9.6]
        at com.fasterxml.jackson.databind.DeserializationContext.handleUnexpectedToken(DeserializationContext.java:1138) ~[jackson-databind-2.9.6.jar:2.9.6]
        at com.fasterxml.jackson.datatype.jsr310.deser.JSR310DeserializerBase._handleUnexpectedToken(JSR310DeserializerBase.java:99) ~[jackson-datatype-jsr310-2.9.6.jar:2.9.6]
        at com.fasterxml.jackson.datatype.jsr310.deser.LocalDateTimeDeserializer.deserialize(LocalDateTimeDeserializer.java:141) ~[jackson-datatype-jsr310-2.9.6.jar:2.9.6]
        at com.fasterxml.jackson.datatype.jsr310.deser.LocalDateTimeDeserializer.deserialize(LocalDateTimeDeserializer.java:39) ~[jackson-datatype-jsr310-2.9.6.jar:2.9.6]
        at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:127) ~[jackson-databind-2.9.6.jar:2.9.6]
        at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:288) ~[jackson-databind-2.9.6.jar:2.9.6]
        at com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeOther(BeanDeserializer.java:189) ~[jackson-databind-2.9.6.jar:2.9.6]
        at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:161) ~[jackson-databind-2.9.6.jar:2.9.6]
        at com.fasterxml.jackson.databind.jsontype.impl.AsPropertyTypeDeserializer._deserializeTypedForId(AsPropertyTypeDeserializer.java:130) ~[jackson-databind-2.9.6.jar:2.9.6]
        at com.fasterxml.jackson.databind.jsontype.impl.AsPropertyTypeDeserializer.deserializeTypedFromObject(AsPropertyTypeDeserializer.java:97) ~[jackson-databind-2.9.6.jar:2.9.6]
        at com.fasterxml.jackson.databind.deser.AbstractDeserializer.deserializeWithType(AbstractDeserializer.java:254) ~[jackson-databind-2.9.6.jar:2.9.6]
        at com.fasterxml.jackson.databind.deser.impl.TypeWrappedDeserializer.deserialize(TypeWrappedDeserializer.java:68) ~[jackson-databind-2.9.6.jar:2.9.6]
        at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4013) ~[jackson-databind-2.9.6.jar:2.9.6]
        at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3004) ~[jackson-databind-2.9.6.jar:2.9.6]
        at mypackage.contracts.data.ContractData.fromJSON(ContractData.java:36) ~[tx-core.jar:na]
        ... 45 common frames omitted

If I instead annotate the LocalDateTime field as

    @JsonSerialize(using = LocalDateTimeSerializer.class)
    @JsonDeserialize(using = LocalDateTimeDeserializer.class)
    private LocalDateTime created;

I get the following serialized output

{"@class":"mypackage.contracts.data.RegistrationContractData","created":[2018,7,20,20,9,20,938000000]}

which deserializes properly. If I keep the field annotated and remove the ObjectMapper.registerModule() calls, it still works. I get the same error for a LocalDate as a LocalDateTime. I haven't tried anything specific to Java 8+ yet.

From what I could glean off older stack exchange posts I am supposed to use ObjectMapper.registerModule with this version instead of the annotations. What have I missed? Why is it not deserializing properly?

Thanks

[Chris C]

/facepalm

As soon as I posted this and returned to the code, I saw the problem. In toJSON() I am creating an ObjectMapper, registering the modules, and then ignoring that and creating a new one to do the serialization.

Sorry for the brain fart.

[Tatu Saloranta]

On Sat, Jul 21, 2018 at 6:00 AM, Chris C <yahoo...@gmail.com> wrote:
> /facepalm
>
> As soon as I posted this and returned to the code, I saw the problem. In
> toJSON() I am creating an ObjectMapper, registering the modules, and then
> ignoring that and creating a new one to do the serialization.

That explains it: serialization indeed looks like java 8 date-time
module was not registered.

>
> Sorry for the brain fart.

Happens to the best of us :)

Thank you for sharing the story,

-+ Tatu +-

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[kaushik tiwari]

hey, what if I want to deserialized the same json which u mentioned in this post.
I have one problem statement on that. Let me know if u have figure out something

{"year":2018,"month":
"JULY","monthValue":7,"dayOfMonth":20,"hour":20,"minute":3,"second":33,"nano":653000000,"dayOfWeek":"FRIDAY","dayOfYear":201,"chronology":{"calendarType":"iso8601","id":"ISO"}}