From a7d03a0086c56c592a0ea65fde692e6d5b712a59 Mon Sep 17 00:00:00 2001
From: "Harry M. You" <myonghyoyou@gmail.com>
Date: Thu, 4 Dec 2025 16:21:35 +0900
Subject: [PATCH] =?UTF-8?q?=ED=8C=8C=EC=9D=BC=EC=B2=B4=ED=81=AC=20?=
 =?UTF-8?q?=EA=B3=B5=ED=86=B5=20=EC=B6=94=EA=B0=80?=
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Content-Type: text/plain; charset=UTF-8
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---
 .../kamcoback/common/utils/FIleChecker.java   | 67 +++++++++++++++++++
 1 file changed, 67 insertions(+)
 create mode 100644 src/main/java/com/kamco/cd/kamcoback/common/utils/FIleChecker.java

diff --git a/src/main/java/com/kamco/cd/kamcoback/common/utils/FIleChecker.java b/src/main/java/com/kamco/cd/kamcoback/common/utils/FIleChecker.java
new file mode 100644
index 00000000..e36f2edd
--- /dev/null
+++ b/src/main/java/com/kamco/cd/kamcoback/common/utils/FIleChecker.java
@@ -0,0 +1,67 @@
+package com.kamco.cd.kamcoback.common.utils;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class FIleChecker {
+
+  public static boolean isValidFile(String pathStr) {
+
+    Path path = Paths.get(pathStr);
+
+    if (!Files.exists(path)) {
+      return false;
+    }
+
+    if (!Files.isRegularFile(path)) {
+      return false;
+    }
+
+    if (!Files.isReadable(path)) {
+      return false;
+    }
+
+    try {
+      if (Files.size(path) <= 0) {
+        return false;
+      }
+    } catch (IOException e) {
+      return false;
+    }
+
+    return true;
+  }
+
+
+  public static boolean verifyFileIntegrity(Path path, String expectedHash)
+    throws IOException, NoSuchAlgorithmException {
+
+    // 1. 알고리즘 선택 (SHA-256 권장, MD5는 보안상 비추천)
+    MessageDigest digest = MessageDigest.getInstance("SHA-256");
+
+    try (InputStream fis = Files.newInputStream(path)) {
+      byte[] buffer = new byte[8192]; // 8KB 버퍼
+      int bytesRead;
+      while ((bytesRead = fis.read(buffer)) != -1) {
+        digest.update(buffer, 0, bytesRead);
+      }
+    }
+
+    // 3. 계산된 바이트 배열을 16진수 문자열로 변환
+    StringBuilder sb = new StringBuilder();
+    for (byte b : digest.digest()) {
+      sb.append(String.format("%02x", b));
+    }
+    String actualHash = sb.toString();
+
+    return actualHash.equalsIgnoreCase(expectedHash);
+  }
+
+}