From a489365977b4e54328b231d2457a2027f4fa5191 Mon Sep 17 00:00:00 2001
From: seonghobae <8172694+seonghobae@users.noreply.github.com>
Date: Mon, 6 Jul 2026 20:47:26 +0000
Subject: [PATCH] =?UTF-8?q?=E2=9A=A1=20Bolt:=20HexFormat=EB=A5=BC=20?=
 =?UTF-8?q?=EC=82=AC=EC=9A=A9=ED=95=9C=20=EB=B0=94=EC=9D=B4=ED=8A=B8=20?=
 =?UTF-8?q?=EB=B0=B0=EC=97=B4-16=EC=A7=84=EC=88=98=20=EB=AC=B8=EC=9E=90?=
 =?UTF-8?q?=EC=97=B4=20=EB=B3=80=ED=99=98=20=EC=84=B1=EB=8A=A5=20=EC=B5=9C?=
 =?UTF-8?q?=EC=A0=81=ED=99=94?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

`String.format`을 루프 안에서 사용하여 바이트 배열을 16진수 문자열로 변환하는 비효율적인 방식을 `java.util.HexFormat.of().formatHex()`를 사용하는 방식으로 변경하여 성능을 개선했습니다.
---
 .../clearfolio/viewer/artifact/ArtifactLinkService.java   | 7 ++-----
 .../viewer/service/DefaultDocumentConversionService.java  | 8 ++------
 2 files changed, 4 insertions(+), 11 deletions(-)

diff --git a/src/main/java/com/clearfolio/viewer/artifact/ArtifactLinkService.java b/src/main/java/com/clearfolio/viewer/artifact/ArtifactLinkService.java
index 454b0448..416d5ead 100644
--- a/src/main/java/com/clearfolio/viewer/artifact/ArtifactLinkService.java
+++ b/src/main/java/com/clearfolio/viewer/artifact/ArtifactLinkService.java
@@ -423,11 +423,8 @@ private static String sha256Hex(byte[] bytes) {
         try {
             MessageDigest digest = MessageDigest.getInstance("SHA-256");
             byte[] raw = digest.digest(bytes);
-            StringBuilder hex = new StringBuilder(raw.length * 2);
-            for (byte b : raw) {
-                hex.append(String.format("%02x", b));
-            }
-            return hex.toString();
+            // Bolt: Using HexFormat for faster byte-to-hex conversion instead of String.format inside a loop.
+            return java.util.HexFormat.of().formatHex(raw);
         } catch (GeneralSecurityException ex) {
             throw new IllegalStateException("SHA-256 digest unavailable", ex);
         }
diff --git a/src/main/java/com/clearfolio/viewer/service/DefaultDocumentConversionService.java b/src/main/java/com/clearfolio/viewer/service/DefaultDocumentConversionService.java
index b8787f35..3397ff72 100644
--- a/src/main/java/com/clearfolio/viewer/service/DefaultDocumentConversionService.java
+++ b/src/main/java/com/clearfolio/viewer/service/DefaultDocumentConversionService.java
@@ -160,12 +160,8 @@ private String contentHash(MultipartFile file) {
             }
 
             byte[] raw = digest.digest();
-            StringBuilder hex = new StringBuilder(raw.length * 2);
-            for (byte b : raw) {
-                hex.append(String.format("%02x", b));
-            }
-
-            return hex.toString();
+            // Bolt: Using HexFormat for faster byte-to-hex conversion instead of String.format inside a loop.
+            return java.util.HexFormat.of().formatHex(raw);
         } catch (NoSuchAlgorithmException ex) {
             throw new IllegalStateException("SHA-256 digest unavailable", ex);
         } catch (IOException ex) {