Configure Jackson to parse multiple date formats

Question

I am working on a project where the date formats returned in JSON payloads aren't consistent (that's another issue all together). The project I'm working on uses Jackson to parse the JSON responses. Right now I've written a few de/serializers to handle it but it's not elegant.

I want to know whether there's a way to configure Jackson with a set of possible date formats to parse for a particular response rather than writing several separate deserializers for each format. Similar to how GSON handles the problem in this question

Why not use a similar approach as mentioned in this GSon solution with just one custom deserializer? — Syam S, Jul 23 '14 at 14:40

score 36 · Answer 1 · edited Oct 20 '22 at 20:10

Here is a Jackson Multi Date Format Serializer.

import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.deser.std.StdDeserializer;

import java.io.IOException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.time.Instant;
import java.util.Arrays;
import java.util.stream.Collectors;

/**
 * https://stackoverflow.com/a/42567051/11152683
 */
public class MultiDateDeserializer extends StdDeserializer<Date> {
    private static final long serialVersionUID = 1L;

    private static final SimpleDateFormat[] DATE_FORMATTERS = new SimpleDateFormat[]{
            new SimpleDateFormat("yyyy-MM-dd HH:mm:ss Z"),
            new SimpleDateFormat("yyyy-MM-dd HH:mm' UTC'")
    };

    public MultiDateDeserializer() {
        this(null);
    }

    public MultiDateDeserializer(Class<?> vc) {
        super(vc);
    }

    @Override
    public Date deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException, JsonProcessingException {
        JsonNode node = jp.getCodec().readTree(jp);
        final String date = node.textValue();

        for (SimpleDateFormat formatter : DATE_FORMATTERS) {
            try {
                return formatter.parse(date); //.toInstant();
            } catch (ParseException e) {
            }
        }
        throw new JsonParseException(jp, "Unparseable date: \"" + date + "\". Supported formats: " +
                Arrays.stream(DATE_FORMATTERS).map(SimpleDateFormat::toPattern).collect(Collectors.joining("; ")));
    }
}

You can use this simply by annotating a field as follows:

@JsonProperty("date") @JsonDeserialize(using = MultiDateDeserializer.class) final Date date,

can also be implemented as follows: SimpleModule module = new SimpleModule(); module.addDeserializer(Date.class,new MultiDateDeserializer()); mapper.registerModule(module); — WhiteWolfza, Aug 11 '22 at 07:38
DO NOT create instance of SimpleDateFormat on each parsing. Save them pre-created similarly like DATE_FORMATS. (I would edit code, if queue was not full). — Lubo, Oct 19 '22 at 21:20
This is an awesome answer, but if someone needs to do this but with LocalDateTime, there are some great options. You can use a DateTimeFormatterBuilder to add optional conditions. More info on that here: https://stackoverflow.com/a/40175568/6477292 — fudge, Mar 01 '23 at 16:57

score 5 · Answer 2 · answered Sep 30 '15 at 15:00

5

In the meanwhile, an annotation became available for a much simpler solution:

public class DateStuff {
    @JsonFormat(shape=JsonFormat.Shape.STRING, pattern="yyyy-MM-dd,HH:00", timezone="CET")
    public Date creationTime;
}

answered Sep 30 '15 at 15:00

Keno

307
3
11

6

@Keno right, but as of now (jackson 2.9.9), this does neither support muliple `@JsonFormat` annotations nor [DateTimeFormatter](https://docs.oracle.com/javase/8/docs/api/java/time/format/DateTimeFormatter.html)-style optional parts. @rouble 's answer is currently the way to go for multiple formats :) – bernard paulus Jul 10 '19 at 15:13

score 5 · Answer 3 · answered Sep 21 '22 at 12:10

You can use the optional section to define multiple formats:

public class DateStuff {
    @JsonFormat(pattern="[MMM dd, yyyy HH:mm:ss][MMM dd, yyyy][yyyy-MM-dd'T'HH:mm:ssZ]")
    public Date creationTime;
    @JsonFormat(pattern="MMM dd, yyyy[ HH:mm:ss]")
    public Date anotherCreationTime;
}

The first defines two completely different formats. The second where only a small portion is optional.

score 1 · Answer 4 · answered Jan 17 '21 at 16:38

1

A better solution is to use StdDateFormat instead. It's Jackson's built-in Date formatter and supports most of the variations of Date formats. Use it like below

StdDateFormat isoDate = new StdDateFormat();
ObjectMapper mapper = new ObjectMapper();
mapper.setDateFormat(isoDate);

answered Jan 17 '21 at 16:38

Code_Worm

4,069
2
30
35

The `StdDateFormat` is already the default `DateFormat` in `ObjectMapper` – Jason White Oct 26 '21 at 22:49

Configure Jackson to parse multiple date formats

4 Answers4

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