diff --git a/src/main/java/org/ntlab/citrusserver/repositories/PublicBookManager.java b/src/main/java/org/ntlab/citrusserver/repositories/PublicBookManager.java
index bfd3b7a..907e5ee 100644
--- a/src/main/java/org/ntlab/citrusserver/repositories/PublicBookManager.java
+++ b/src/main/java/org/ntlab/citrusserver/repositories/PublicBookManager.java
@@ -29,23 +29,7 @@
     }
 
     public ArrayList<Book> getAllPublicBooks(int sortBy){
-        if(sortBy == 0){
-            ArrayList<Book> books = getAllPublicBooks();
-            books.sort(Comparator.comparing(Book::getTime).reversed());
-            return books;
-        } else if(sortBy == 1){
-            ArrayList<BookForSort> books = new ArrayList<>();
-            for(Book book : getAllPublicBooks()){
-                books.add(new BookForSort(book, favoriteManager.getFavorited(book.getAccountId(), book.getBookId()).size()));
-            }
-            books.sort(Comparator.comparing(BookForSort::favoriteNum));
-            ArrayList<Book> res = new ArrayList<>();
-            for(BookForSort book : books){
-                res.add(book.book());
-            }
-            return res;
-        }
-        return null;
+        return sort(getAllPublicBooks(), sortBy);
     }
 
     public ArrayList<Book> searchBooksByTitle(String title){
@@ -63,24 +47,7 @@
 
 
     public ArrayList<Book> searchBooksByTitle(String title, int sortBy){
-        if(sortBy == 0){
-            ArrayList<Book> result = searchBooksByTitle(title);
-            result.sort(Comparator.comparing(Book::getTime).reversed());
-            return result;
-        }else if(sortBy == 1){
-            ArrayList<BookForSort> books = new ArrayList<>();
-            for(Book book : searchBooksByTitle(title)){
-                books.add(new BookForSort(book, favoriteManager.getFavorited(book.getAccountId(), book.getBookId()).size()));
-            }
-            books.sort(Comparator.comparing(BookForSort::favoriteNum));
-            ArrayList<Book> res = new ArrayList<>();
-            for(BookForSort book : books){
-                res.add(book.book());
-            }
-            return res;
-
-        }
-        return null;
+        return sort(searchBooksByTitle(title), sortBy);
     }
 
     public ArrayList<Book> searchBooksByAccount(String accountId){
@@ -96,23 +63,7 @@
     }
 
     public ArrayList<Book> searchBooksByAccount(String accountId, int sortBy){
-        if(sortBy == 0){
-            ArrayList<Book> result = searchBooksByAccount(accountId);
-            result.sort(Comparator.comparing(Book::getTime).reversed());
-            return result;
-        } else if(sortBy == 1){
-            ArrayList<BookForSort> books = new ArrayList<>();
-            for(Book book : searchBooksByAccount(accountId)){
-                books.add(new BookForSort(book, favoriteManager.getFavorited(book.getAccountId(), book.getBookId()).size()));
-            }
-            books.sort(Comparator.comparing(BookForSort::favoriteNum));
-            ArrayList<Book> res = new ArrayList<>();
-            for(BookForSort book : books){
-                res.add(book.book());
-            }
-            return res;
-        }
-        return null;
+        return sort(searchBooksByAccount(accountId), sortBy);
     }
 
     public ArrayList<Book> searchBooksByTitleAndAccount(String title, String accountId){
@@ -127,23 +78,7 @@
     }
 
     public ArrayList<Book> searchBooksByTitleAndAccount(String title, String accountId, int sortBy){
-        if (sortBy == 0) {
-            ArrayList<Book> result = searchBooksByTitleAndAccount(title, accountId);
-            result.sort(Comparator.comparing(Book::getTime).reversed());
-            return result;
-        } else if(sortBy == 1){
-            ArrayList<BookForSort> books = new ArrayList<>();
-            for(Book book : searchBooksByTitleAndAccount(title, accountId)){
-                books.add(new BookForSort(book, favoriteManager.getFavorited(book.getAccountId(), book.getBookId()).size()));
-            }
-            books.sort(Comparator.comparing(BookForSort::favoriteNum));
-            ArrayList<Book> res = new ArrayList<>();
-            for(BookForSort book : books){
-                res.add(book.book());
-            }
-            return res;
-        }
-        return null;
+        return sort(searchBooksByTitleAndAccount(title, accountId), sortBy);
     }
 
     @Override
@@ -164,6 +99,27 @@
     public void bookDeleted(Account account, Book book) {
 
     }
+
+    private ArrayList<Book> sort(ArrayList<Book> books, int sortMode){
+        switch(sortMode){
+            case 0:
+                books.sort(Comparator.comparing(Book::getTime).reversed());
+                return books;
+            case 1:
+                ArrayList<BookForSort> booksForSort = new ArrayList<>();
+                for(Book book : books){
+                    booksForSort.add(new BookForSort(book, favoriteManager.getFavorited(book.getAccountId(), book.getBookId()).size()));
+                }
+                booksForSort.sort(Comparator.comparing(BookForSort::favoriteNum).reversed());
+                ArrayList<Book> res = new ArrayList<>();
+                for(BookForSort book : booksForSort){
+                    res.add(book.book());
+                }
+                return res;
+        }
+        return new ArrayList<>();
+    }
+
 }
 
 record BookForSort(Book book, Integer favoriteNum) {