Retrofit Date Parse without Custom Class

Question

In Application, i am using Retrofit to consume api data. As converter i am using Gson

new GsonBuilder()
.setDateFormat("yyyy-MM-dd")
.create();

I am getting Date types like below from api. But i cannot convert it to java.util.Date object.

{
   "date":{
      "year":2018,
      "month":2,
      "day":11
   },
   "time":{
      "hour":22,
      "minute":40,
      "second":0,
      "nano":0
   }
}

To get this type of date i create new classes named CustomDate, CustomTime, CustomDateTime.

CustomDate

public class CustomDate implements Serializable{
    private int year;
    private int month;
    private int day;

CustomTime

public class CustomTime implements Serializable {
    private int hour;
    private int minute;
    private int second;
    private int nano;

CustomDateTime

public class CustomDateTime implements Serializable {

    private CustomDate date;
    private CustomTime time;

My question is how can i convert consumed data without above custom classes.What i actually want is dateformatter. What should i put .setDateFormat("") to handle date conversion.

Answer 1

Try this code that i am used in my app

String string = "2018-03-09T03:02:10.823Z";
String pattern = "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'";
Date date = new SimpleDateFormat(pattern).parse(string);
System.out.println(date);

To convert it to Calendar

Calendar calendar = Calendar.getInstance();
calendar.setTime(date);

Answer 2

After some research i found that to make date to be deserialized, there should be a deserializer. When i create gson object, i needed to set this deserializer as adapter for GsonBuilder(). @SaravInfer answer and @Hemant comment gave me a clue to create date from jsonObject.

Deserializer

public class DateDeserializer implements JsonDeserializer<Date> {

    @Override
    public Date deserialize(JsonElement element, Type arg1, JsonDeserializationContext arg2) throws JsonParseException {
        Calendar calendar = null;
        if (element.isJsonObject()) {
            calendar = Calendar.getInstance();
            JsonObject jsonObject = element.getAsJsonObject();
            if (jsonObject.has("date")) {
                JsonElement dateElement = jsonObject.get("date");
                if (dateElement.isJsonObject()) {
                    JsonObject dateObject = dateElement.getAsJsonObject();
                    JsonElement year = dateObject.get("year");
                    JsonElement month = dateObject.get("month");
                    JsonElement day = dateObject.get("day");
                    calendar.set(Calendar.YEAR, year.getAsInt()); 
                    calendar.set(Calendar.MONTH, month.getAsInt() - 1);
                    calendar.set(Calendar.DAY_OF_MONTH, day.getAsInt());    
                }
            }


            if (jsonObject.has("time")) {
                JsonElement timeElement = jsonObject.get("time");
                JsonObject timeObject = timeElement.getAsJsonObject();
                JsonElement hour = timeObject.get("hour");
                JsonElement minute = timeObject.get("minute");
                JsonElement second = timeObject.get("second");
                JsonElement nano = timeObject.get("nano");
                calendar.set(Calendar.HOUR_OF_DAY, hour.getAsInt());
                calendar.set(Calendar.MINUTE, minute.getAsInt());
                calendar.set(Calendar.SECOND, second.getAsInt());
                calendar.set(Calendar.MILLISECOND, nano.getAsInt());
            } else {
                calendar.set(Calendar.HOUR_OF_DAY, 0);
                calendar.set(Calendar.MINUTE, 0); 
                calendar.set(Calendar.SECOND, 0); 
                calendar.set(Calendar.MILLISECOND, 0);
            }

        }
        if (calendar != null) {
            return calendar.getTime();
        } else {
            return null;
        }
    }
}

When i create gson ;

new GsonBuilder()
    .registerTypeAdapter(Date.class, new DateDeserializer())
    .create();

Answer 3

Try like this if you want to set date and time from the gson

 Date date = new Date();
 Calendar calendar = Calendar.getInstance();
 calendar.set(Calendar.DAY_OF_MONTH, CustomDate.date);// your date object.value
 calendar.set(Calendar.YEAR, CustomDate.year); //your date object.value
 calendar.set(Calendar.MONTH, CustomDate.month); //your date object.value
 calendar.set(Calendar.HOUR_OF_DAY, CustomTime.hour); //your time object.value
 calendar.set(Calendar.MINUTE, CustomTime.minute);//your time object.value
 calendar.set(Calendar.SECOND, CustomTime.second);//your time object.value
 System.out.println(calendar.getTime());