SoftWeather Forecast

@Override
    public String importCities() throws IOException {
        StringBuilder sb = new StringBuilder();

        ImplementCityDto[] implementCityDtos = this.gson.fromJson(
                new FileReader((CITY_PATH)),ImplementCityDto[].class);

        for (ImplementCityDto implementCityDto:implementCityDtos){

            Optional<City> optional = this.cityRepository.
                    findByCityName(implementCityDto.getCityName());
            if (!this.validationUtil.isValid(implementCityDto)|| optional.isPresent()){
                sb.append("Invalid city\n");
                continue;

            }
            Optional<Country> countryOptional = countryRepository.findById(implementCityDto.getCountry());
            if (!countryOptional.isPresent()) {
                sb.append("Invalid country \n");
                continue;
            }
            City city = this.modelMapper.map(implementCityDto,City.class);
            city.setCountry(countryOptional.get());
            this.cityRepository.saveAndFlush(city);

            sb.append(String.format("Successfully imported city  %s - %d\n", city.getCityName(),city.getPopulation()));

        }
        return sb.toString();