♻️ [Refactor]: 책 추천 할때 나이를 나이 분류로 변환하게 변경

src/main/java/com/beyondB/beyondB/controller/BookController.java

@@ -72,8 +72,8 @@ public BaseResponse<BookResponseDTO.DetailBookDTO> getDetailBook(@AuthUser User
     @GetMapping("/recommend")
     @Parameter(name = "user", hidden = true)
     public BaseResponse<BookResponseDTO.BookContentDTO> recommendBook(
-            @RequestParam Emotion emotion, @RequestParam Age age, @AuthUser User user) {
-        Book book = bookService.recommendBook(emotion, age, user);
+            @RequestParam Emotion emotion, @AuthUser User user) {
+        Book book = bookService.recommendBook(emotion, user);
 
         return BaseResponse.onSuccess(BookConverter.toCreateBookDTO(book));
     }

src/main/java/com/beyondB/beyondB/service/BookService.java

@@ -19,7 +19,7 @@ public interface BookService {
 
     BookResponseDTO.DetailBookDTO getDetailBook(User user, Long bookId);
 
-    Book recommendBook(Emotion emotion, Age age, User user);
+    Book recommendBook(Emotion emotion, User user);
 
     Long recentQuiz(User user);
 }

src/main/java/com/beyondB/beyondB/service/impl/BookServiceImpl.java

@@ -101,13 +101,13 @@ public BookResponseDTO.DetailBookDTO getDetailBook(User user, Long bookId) {
     }
 
     @Override
-    public Book recommendBook(Emotion emotion, Age age, User user) {
+    public Book recommendBook(Emotion emotion, User user) {
         Feeling feeling = feelingRepository.findByEmotion(emotion);
         List<Book> books = bookRepository.findAllByFeeling(feeling);
         if (books.isEmpty()) {
             throw new BookException(ErrorStatus.BOOK_NOT_FOUND);
         }
-
+        Age age = stringToAge(user.getAge());
         List<Long> readBookIds = user.getUserBookList().stream()
                 .map(userBook -> userBook.getBook().getId())
                 .collect(Collectors.toList());
@@ -191,4 +191,27 @@ private boolean isImageUrlValid(String imageUrl) {
             return false;
         }
     }
+
+    private Age stringToAge(String ageString) {
+        int age;
+        try {
+            age = Integer.parseInt(ageString);
+        } catch (NumberFormatException e) {
+            throw new IllegalArgumentException("Invalid age format");
+        }
+
+        if (age < 7) {
+            return Age.UNDER_7;
+        } else if (age <= 10) {
+            return Age.AGE_7_10;
+        } else if (age <= 13) {
+            return Age.AGE_11_13;
+        } else if (age <= 16) {
+            return Age.AGE_14_16;
+        } else if (age <= 19) {
+            return Age.AGE_17_19;
+        } else {
+            return Age.OVER_18;
+        }
+    }
 }

src/main/java/com/beyondB/beyondB/service/impl/UserServiceImpl.java

@@ -33,10 +33,6 @@ public void signUp(UserSignupDTO userSignUpDto) throws Exception {
             throw new Exception("이미 존재하는 이메일입니다.");
         }
 
-        if (userRepository.findByUsername(userSignUpDto.getUsername()).isPresent()) {
-            throw new Exception("이미 존재하는 닉네임입니다.");
-        }
-
         User user = User.builder()
                 .email(userSignUpDto.getEmail())
                 .password(userSignUpDto.getPassword())