Gson: set date format for timestamp and timezone

Question

Which model should be used for date format 1418805300000-0100? (Timestamp and Time Zone)

GsonBuilder().setDateFormat("?????????????-Z")

Decision:

• create a new GSON with adapters

  private static Gson createGson(){
  return new GsonBuilder().disableHtmlEscaping()
          .registerTypeHierarchyAdapter(Date.class, new DateTimeSerializer())
          .registerTypeHierarchyAdapter(Date.class, new DateTimeDeserializer())
          .create();
  }
  
  
  public static MyClass fromJson(String json) {
      return createGson().fromJson(json, MyClass.class);
  }
  
  public  String toJson() {
      return createGson().toJson(this);
  }
  

• JSON Serial Number

  private static class DateTimeSerializer implements JsonSerializer<Date> {
      @Override
      public JsonElement serialize(Date src, Type typeOfSrc, JsonSerializationContext context) {
          //  hodgie code
          return new JsonPrimitive(src.getTime() + new SimpleDateFormat("Z").format(src));
      }
  }
  

• deserializer

  private static class DateTimeDeserializer implements JsonDeserializer<Date> {
  
      @Override
      public Date deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
      // hodgie code
      return new Date(Long.valueOf((json).getAsString().substring(0, 13)));
      }
  }
  

Answer 1

GsonBuilder#setDateFormat(String)uses Stringas an argument to create instances SimpleDateFormat. SimpleDateFormatdoes not provide templates for creating timestamps. setDateFormatyou cannot achieve what you want. Custom TypeAdapterseems appropriate.