Jackson - Can't deserialize datetime with timezone offset 'unparsed text found at index 23'

Question

My datetime has to come from frontend with timezone offset: 2017-07-04T06:00:00.000+01:00

I cannot deserialize it with Jackson. The error is:

Text '2017-07-04T06:00:00.000+01:00' could not be parsed, unparsed text found at index 23;

I was trying to Google the solution by all are about DateTime with Z at the end.

    @NotNull
    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd'T'HH:mm:ss.SSS aZ")
    private LocalDateTime time;

Is there any solution for that?

Materiel

There is. You should probably give us the details about how the parsing was supposed to happen, maybe show us some code. – Stubbs

added the code, sorry – Materiel

With next to no Jackson experience I’m probably shooting blindfolded: your string seems to match an OffsetDateTime, so what happens if you change your type to that and leave out the pattern? – Stubbs

Are Jackson patterns like DateTimeFormatter patterns? If so, should it be yyyy-MM-dd'T'HH:mm:ss.SSSZ? (no space, no a) – Stubbs

@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd'T'HH:mm:ss.SSSZ") private OffsetDateTime time; Still not working – Materiel

Answer 1

The pattern a is used to parse AM/PM, which is not in the input String, that's why you get a parse error.

The input format matches an OffsetDateTime, which can be parsed with the respective built-in formatter DateTimeFormatter.ISO_OFFSET_DATE_TIME, so you can use this formatter in a deserializer object and register it in the module. You must also remove the JsonFormat annotation from the field.

ObjectMapper om = new ObjectMapper();
JavaTimeModule module = new JavaTimeModule();
LocalDateTimeDeserializer deserializer = new LocalDateTimeDeserializer(DateTimeFormatter.ISO_OFFSET_DATE_TIME);
module.addDeserializer(LocalDateTime.class, deserializer);
om.registerModule(module);

This will parse the input and convert it to a LocalDateTime. In the test I've made, the value of LocalDateTime was set to 2017-07-04T06:00.

---

To control the output, you can either do:

om.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);

Which will output the LocalDateTime as 2017-07-04T06:00:00, or you can use a custom formatter:

LocalDateTimeSerializer serializer = new LocalDateTimeSerializer(DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss.SSS a"));
module.addSerializer(LocalDateTime.class, serializer);

The serializer above will output the field as 2017-07-04T06:00:00.000 AM. Please note that the Z pattern will not work because a LocalDateTime has no timezone information and it can't resolve its offset - because when you deserialized to a LocalDateTime, the offset information in the input (+01:00) was lost.

---

Another alternative (without the need to configure the object mapper) is to use the correct pattern in the annotation:

@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd'T'HH:mm:ss.SSS[xxx]")
private LocalDateTime time;

Note that I used the pattern [xxx] because the offset (+01:00) can be optional: when deserializing, this information is lost becase a LocalDateTime has no information about timezones and offsets, so when serializing this field won't be found - making the field optional (using [] delimiters) make it work for both deserialization and serialization.

This will deserialize the input 2017-07-04T06:00:00.000+01:00 and serialize to 2017-07-04T06:00:00.000 (note that the optional offset is not used in serialization, as the LocalDateTime has no such information).

---

If you want different formats for deserialization and serialization, you can also create custom classes and anotate them in the field:

public class CustomDeserializer extends LocalDateTimeDeserializer {
    public CustomDeserializer() {
        super(DateTimeFormatter.ISO_OFFSET_DATE_TIME);
    }
}

public class CustomSerializer extends LocalDateTimeSerializer {
    public CustomSerializer() {
        super(DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss.SSS a"));
    }
}

// in this case, don't use @JsonFormat
@JsonSerialize(using = CustomSerializer.class)
@JsonDeserialize(using = CustomDeserializer.class)
private LocalDateTime time;

This will use the format 2017-07-04T06:00:00.000+01:00 for deserialize and the format 2017-07-04T06:00:00.000 AM to serialize.

Orchestrate

would be nice if you could elaborate more how to really implement it as I am a little bit lost, but your solution looks good so I'd like to get know how to use it – Materiel

The object mapper is used to serialize and deserialize. How are you doing the deserialization? – Orchestrate

automatically with Jackson – Materiel

so good. Made it in seperate file to make it reusable across whole project. Great! – Materiel