refactor: Spring AI 응답 반환 로직 개선

src/main/java/com/spots/domain/ai/service/RecommendLLMService.java

@@ -1,21 +1,19 @@
 package com.spots.domain.ai.service;
 
-import static com.spots.global.exception.Code.INVALID_JSON_RESPONSE;
+
 import static com.spots.global.exception.Code.JSON_CONVERSION_ERROR;
 import static com.spots.global.exception.Code.LLM_INTERRUPT_ERROR;
-import static com.spots.global.exception.Code.PROMPT_LOADING_ERROR;
-import static java.nio.charset.StandardCharsets.UTF_8;
 
-import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.spots.domain.ai.dto.request.RecommendLLMRequest;
 import com.spots.domain.ai.dto.response.WeeklyRecommendResponse;
 import com.spots.global.exception.CustomException;
-import java.io.InputStream;
 import java.util.concurrent.Semaphore;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.ai.chat.client.ChatClient;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.core.io.Resource;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 import org.springframework.util.StopWatch;
@@ -28,7 +26,11 @@ public class RecommendLLMService {
 
   private final ChatClient chatClient;
   private final ObjectMapper objectMapper;
-  private final Semaphore llmSemaphore = new Semaphore(5);
+  private final int MAX_CONCURRENT_LLM_CALLS = 5;
+  private final Semaphore llmSemaphore = new Semaphore(MAX_CONCURRENT_LLM_CALLS);
+
+  @Value("classpath:prompt/routineV4.prompt")
+  private Resource systemPromptResource;
 
   public WeeklyRecommendResponse createWeeklyPlan(RecommendLLMRequest request) {
     StopWatch stopWatch = new StopWatch("LLM_Generation_Task");
@@ -39,40 +41,32 @@ public WeeklyRecommendResponse createWeeklyPlan(RecommendLLMRequest request) {
       stopWatch.stop();
 
       stopWatch.start("2. Prompt & JSON Prep");
-      String systemMessage = loadPrompt("prompt/routineV4.prompt");
+      String userJson = toJson(request);
       String userMessage = """
           아래는 사용자 정보와 후보 운동 프로그램 목록입니다.
           이를 기반으로 일주일 운동 루틴 포토카드를 만들 JSON을 생성해주세요.
 
           <user_data>
           %s
           </user_data>
-          """.formatted(toJson(request));
+          """.formatted(userJson);
       stopWatch.stop();
 
       stopWatch.start("3. LLM API Call (External)");
-      String llmResponse = chatClient
-              .prompt()
-              .system(systemMessage)
-              .user(userMessage)
-              .call()
-              .content();
-      stopWatch.stop();
-
-      stopWatch.start("4. Response Parsing");
-      WeeklyRecommendResponse response = objectMapper.readValue(sanitize(llmResponse), WeeklyRecommendResponse.class);
+      WeeklyRecommendResponse response = chatClient
+          .prompt()
+          .system(s -> s.text(systemPromptResource))
+          .user(userMessage)
+          .call()
+          .entity(WeeklyRecommendResponse.class);
       stopWatch.stop();
 
       log.info(stopWatch.prettyPrint());
-
       return response;
 
     } catch (InterruptedException e) {
       Thread.currentThread().interrupt();
       throw new CustomException(LLM_INTERRUPT_ERROR);
-    } catch (JsonProcessingException e) {
-      log.error("JSON 파싱 실패. Raw Response: {}", e.getMessage());
-      throw new CustomException(INVALID_JSON_RESPONSE);
     } catch (Exception e) {
       log.error("LLM 호출 중 알 수 없는 에러 발생", e);
       throw new CustomException(LLM_INTERRUPT_ERROR);
@@ -81,27 +75,11 @@ public WeeklyRecommendResponse createWeeklyPlan(RecommendLLMRequest request) {
     }
   }
 
-  private String loadPrompt(String filename) {
-    try {
-      InputStream in = getClass().getClassLoader().getResourceAsStream(filename);
-      return new String(in.readAllBytes(), UTF_8);
-    } catch (Exception e) {
-      throw new CustomException(PROMPT_LOADING_ERROR);
-    }
-  }
-
   private String toJson(Object obj) {
     try {
       return objectMapper.writeValueAsString(obj);
     } catch (Exception e) {
       throw new CustomException(JSON_CONVERSION_ERROR);
     }
   }
-
-  private String sanitize(String raw) {
-    return raw
-            .replaceAll("(?i)```json", "")
-            .replaceAll("```", "")
-            .trim();
-  }
 }