Serialization for Java Calendar

Question

How to create custom serialization for java calendar for json by extending json serializer<Calendar>?

I have tried the same for java.until.Dateand it works. In the serialization method, I converted Date to String and wrote it in json format.

The sample code made for java.util.Date is similar to the code below

  public class CDJsonDateSerializer extends JsonSerializer<Date>{
  @Override
  public void serialize(Date date, JsonGenerator jsonGenerator,SerializerProvider provider)
 throws IOException {

      SimpleDateFormat dateFormat = new SimpleDateFormat("MM/dd/yyyy");
      String dateString = dateFormat.format(date);
     jsonGenerator.writeString(dateString);
 }
}

And it is used like this:

 @JsonSerialize(using = CDJsonDateSerializer.class)
 private Date startDate;

What can I do to serialize a calendar in java for json without losing data in a Calendar object?

Answer 1

From json to Calendar

Create JsonSerializer:

public class CalendarSerializer extends JsonSerializer<Calendar> {

    private SimpleDateFormat formatter = new SimpleDateFormat("MM/dd/yyyy");

    @Override
    public void serialize(Calendar calendar, JsonGenerator jsonGenerator,
                          SerializerProvider serializerProvider) throws IOException {

        String dateAsString = formatter.format(calendar.getTime());
        jsonGenerator.writeString(dateAsString);

    }
}

And then use it:

@JsonSerialize(using = CalendarSerializer.class)
private Calendar calendar;

From Calendarto JSON

Create JsonDeserializer:

public class CalendarDeserializer extends JsonDeserializer<Calendar> {

    private SimpleDateFormat formatter = new SimpleDateFormat("MM/dd/yyyy");

    @Override
    public Calendar deserialize(JsonParser jsonParser,
                                DeserializationContext deserializationContext) 
                                throws IOException {

        String dateAsString = jsonParser.getText();

        try {
            Date date = formatter.parse(dateAsString);
            Calendar calendar = Calendar.getInstance();
            calendar.setTime(date);
            return calendar;
        } catch (Exception e) {
            throw new IOException(e);
        }
    }

And then use it:

@JsonDeserialize(using = CalendarDeserializer.class)
private Calendar calendar;

Answer 2

, json, , Gson:

JsonObject albums = new JsonObject();

albums.addProperty("date", new Date());

json , , , , :

public String toJson() {
        Gson gson = new Gson();

        return gson.toJson(this);
    }