Retrofit GSON serialize Date from json string into java.util.date

Gson gson = new GsonBuilder()    .setDateFormat("yyyy-MM-dd'T'HH:mm:ss")    .create();RestAdapter restAdapter = new RestAdapter.Builder()    .setEndpoint(API_BASE_URL)    .setConverter(new GsonConverter.create(gson))    .build();

Or the Kotlin equivalent:

val gson = GsonBuilder().setDateFormat("yyyy-MM-dd'T'HH:mm:ss").create()RestAdapter restAdapter = Retrofit.Builder()    .baseUrl(API_BASE_URL)    .addConverterFactory(GsonConverterFactory.create(gson))    .build()    .create(T::class.java)

You can set your customized Gson parser to retrofit. More here: Retrofit Website

Look at Ondreju's response to see how to implement this in retrofit 2.

@gderaco's answer updated to retrofit 2.0:

Gson gson = new GsonBuilder().setDateFormat("yyyy-MM-dd'T'HH:mm:ss").create();Retrofit retrofitAdapter = new Retrofit.Builder().baseUrl(API_BASE_URL).addConverterFactory(GsonConverterFactory.create(gson)).build();

Here is how I did it:

Create DateTime class extending Date and then write a custom deserializer:

public class DateTime extends java.util.Date {    public DateTime(long readLong) {        super(readLong);    }    public DateTime(Date date) {        super(date.getTime());    }       }

Now for the deserializer part where we register both Date and DateTime converters:

public static Gson gsonWithDate(){    final GsonBuilder builder = new GsonBuilder();    builder.registerTypeAdapter(Date.class, new JsonDeserializer<Date>() {          final DateFormat df = new SimpleDateFormat("yyyy-MM-dd");          @Override          public Date deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {              try {                  return df.parse(json.getAsString());              } catch (final java.text.ParseException e) {                  e.printStackTrace();                  return null;              }          }    });    builder.registerTypeAdapter(DateTime.class, new JsonDeserializer<DateTime>() {          final DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");          @Override          public DateTime deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {              try {                  return new DateTime(df.parse(json.getAsString()));              } catch (final java.text.ParseException e) {                e.printStackTrace();                  return null;              }          }    });    return builder.create();}

And when you create your RestAdapter, do the following:

new RestAdapter.Builder().setConverter(gsonWithDate());

Your Foo should look like this:

class Foo {    Date date;    DateTime created_at;}