Spring boot 업로드 파일명 중복 피하기

filePath 정보를 계속 변경해서 while문으로 존재여부를 확인하는게 중요

@PostMapping("/upload")
public ResponseEntity<String> handleFileUpload(@RequestParam("file") MultipartFile file) throws IOException {
    // Define the directory where files will be saved
    String uploadDir = "uploads/";

    // Ensure the directory exists
    Path uploadPath = Paths.get(uploadDir);
    if (!Files.exists(uploadPath)) {
        Files.createDirectories(uploadPath);
    }

    // Get the original filename and extension
    String originalFilename = file.getOriginalFilename();
    String name = originalFilename.contains(".")
            ? originalFilename.substring(0, originalFilename.lastIndexOf('.'))
            : originalFilename;
    String extension = originalFilename.contains(".")
            ? originalFilename.substring(originalFilename.lastIndexOf('.'))
            : "";

    // Initialize counter by finding existing files with matching patterns
    int counter = 0;
    String newFilename = originalFilename;
    Path filePath = uploadPath.resolve(newFilename);

    // Increment counter until no duplicate is found
    while (Files.exists(filePath)) {
        counter++;
        newFilename = name + "(" + counter + ")" + extension;
        filePath = uploadPath.resolve(newFilename);
    }

    // Save the uploaded file with a unique name
    Files.copy(file.getInputStream(), filePath, StandardCopyOption.REPLACE_EXISTING);
    return ResponseEntity.ok("File uploaded successfully as " + newFilename);
}