fix: 공공데이터포털 빈 응답 파싱 오류로 인한 500 에러 수정

src/main/java/sdung/ongil/domain/environment/service/EnvironmentService.java

@@ -25,7 +25,9 @@ public WeatherResponseDto getWeather(double lat, double lng) {
         GridConverter.Grid grid = GridConverter.toGrid(lat, lng);
         KmaWeatherApiResponse response = kmaWeatherClient.getUltraSrtNcst(grid.nx(), grid.ny());
 
-        List<KmaWeatherApiResponse.Item> items = response.getResponse().getBody().getItems().getItem();
+        KmaWeatherApiResponse.Items itemsWrapper = response.getResponse().getBody().getItems();
+        List<KmaWeatherApiResponse.Item> items =
+                (itemsWrapper == null || itemsWrapper.getItem() == null) ? List.of() : itemsWrapper.getItem();
         Map<String, String> values = items.stream()
                 .collect(Collectors.toMap(
                         KmaWeatherApiResponse.Item::getCategory,
@@ -45,7 +47,10 @@ public WeatherResponseDto getWeather(double lat, double lng) {
     public SafetyResponseDto getSafety(double lat, double lng) {
         String sidoName = kakaoRegionClient.getSidoName(lat, lng);
         AirKoreaApiResponse response = airKoreaClient.getRealtimeDensityBysido(sidoName);
-        List<AirKoreaApiResponse.Item> items = response.getResponse().getBody().getItems();
+
+        List<AirKoreaApiResponse.Item> rawItems = response.getResponse().getBody().getItems();
+        List<AirKoreaApiResponse.Item> items = rawItems == null ? List.of() : rawItems;
+
         AirKoreaApiResponse.Item nearest = items.isEmpty() ? null : items.get(0);
         Integer pm10 = nearest == null ? null : parseInt(nearest.getPm10Value());
         Integer pm25 = nearest == null ? null : parseInt(nearest.getPm25Value());

src/main/java/sdung/ongil/domain/environment/service/RestTemplateConfig.java

@@ -1,13 +1,22 @@
 package sdung.ongil.domain.environment.service;
 
+import com.fasterxml.jackson.databind.DeserializationFeature;
+import com.fasterxml.jackson.databind.ObjectMapper;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
 import org.springframework.web.client.RestTemplate;
 
 @Configuration
+@SuppressWarnings("removal")
 public class RestTemplateConfig {
     @Bean
     public RestTemplate restTemplate() {
-        return new RestTemplate();
+        ObjectMapper objectMapper = new ObjectMapper();
+        objectMapper.configure(DeserializationFeature.ACCEPT_EMPTY_STRING_AS_NULL_OBJECT, true);
+        MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter(objectMapper);
+        RestTemplate restTemplate = new RestTemplate();
+        restTemplate.getMessageConverters().add(0, converter);
+        return restTemplate;
     }
 }