JAVA StdDateSerializer parsing Date

Question

I have custom Date serializer to add certain timezone.

public class DateDeserializer extends StdDeserializer<Date> {

    public DateDeserializer() {
        this(null);
    }

    protected DateDeserializer(Class<?> vc) {
        super(vc);
    }

    @Override
    public Date deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException {
        Long dateString = jsonParser.getLongValue();
        Date date = new Date(dateString);
        changeTimeZone(date);
        return date;
    }
}

But sometimes the date doesn't come as long value. Sometimes it comes like String , for example "2017-01-01" and method jsonParser.getLongValue() fails.

Is there some way to know what kind of value jsonParser is holding? Because if I check jsonParser instanceof String or long it always returns false .

Answer 1

You can use the getCurrentToken() method and compare with the JsonToken values :

switch (jsonParser.getCurrentToken()) {
    case VALUE_STRING:
        // get String value
        break;

    case VALUE_NUMBER_INT:
        // get int or long value
        break;
        // and so on
}

Or using if :

if (jsonParser.getCurrentToken() == JsonToken.VALUE_STRING) {
    // get String value
} else if (jsonParser.getCurrentToken() == JsonToken.VALUE_NUMBER_INT) {
    // get long value
}
... etc

Answer 2

If your date is String type for example like this mask: "yyyy-MM-dd"

you can use in your deserialize method:

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
Date date = sdf.parse(dateString);