How to convert uploadedFile to file without giving path in struts2 spring

I need to use ActionUploadFileInterceptor. I implement UploadedFilesAware and need to convert UploadedFile to File. I write a method for convertUploadedFileToFile.

Is there any better way to convert uploadFile to a File in Struts?

Is it correct convertUploadedFileToFile()? What is type of uploadedFile.getContent()? Here is my code:

@ConversationController
public class SampleAction extends BaseActionSupport implements UploadedFilesAware {

    private List<UploadedFile> uploadedFiles;
    public String upload() {
        if (uploadedFiles != null && !uploadedFiles.isEmpty()) {
            for (UploadedFile file : uploadedFiles) {
                String fileName = file.getOriginalName(); // Get the file name
                LOG.debug("uploading file for OwnToOther Batch {}", fileName);
                String ext = FilenameUtils.getExtension(fileName);
                if (ext.equalsIgnoreCase("xlsx") || ext.equalsIgnoreCase("xls")) {
                    processExcelFile(file);
                } else {
                    processCSVFile(file);
                }
            }
        }
        setGridModel(transferVOList.getFundTransferList());

        return SUCCESS;
    }

    private void processExcelFile(UploadedFile uploadedFile) {

        List<List<String>> dataEntriesList;
        List<FundTransferVO> transVOList;
        try {
            File file = convertUploadedFileToFile(uploadedFile);
            dataEntriesList = excelReader.read(file, COLUMN_NUMBER);
            transVOList = excelReader.populateBeans(dataEntriesList);
            // ...

        } catch (IOException ex) {
            LOG.error("Error in reading the uploaded excel file: ", ex);
        } catch (InvalidFormatException ex) {
            LOG.error("File format error while reading the uploaded excel file:", ex);
        }
    }

    private File convertUploadedFileToFile(UploadedFile uploadedFile) throws IOException {
        File file = new File(uploadedFile.getOriginalName());
        Object contentObject = uploadedFile.getContent();
        if (contentObject instanceof InputStream) {
            try (InputStream inputStream = (InputStream) contentObject;
                    FileOutputStream outputStream = new FileOutputStream(file)) {
                byte[] buffer = new byte[1024];
                int bytesRead;
                while ((bytesRead = inputStream.read(buffer)) != -1) {
                    outputStream.write(buffer, 0, bytesRead);
                }
            }
        } else if (contentObject instanceof byte[]) {
            byte[] content = (byte[]) contentObject;
            try (FileOutputStream outputStream = new FileOutputStream(file)) {
                outputStream.write(content);
            }
        } else if (contentObject instanceof String) {
            String content = (String) contentObject;
            try (FileOutputStream outputStream = new FileOutputStream(file)) {
                outputStream.write(content.getBytes());
            }
        } else if (contentObject instanceof File) {
            File contentFile = (File) contentObject;
            Files.copy(contentFile.toPath(), file.toPath(), StandardCopyOption.REPLACE_EXISTING);
        } else {
            throw new IOException("Unsupported content type: " + contentObject.getClass().getName());
        }

        return file;
    }
    @Override
    public void withUploadedFiles(List<UploadedFile> uploadedFiles) {
        this.uploadedFiles = uploadedFiles;
    }
}

Is there any better way to convert uploadFile to a File in Struts?

If you need to use actionFileUpload interceptor then you should read Action File Upload Interceptor.

Interceptor that is based off of MultiPartRequestWrapper, which is automatically applied for any request that includes a file. If an action implements org.apache.struts2.action.UploadedFilesAware interface, the interceptor will pass information and content of uploaded files using the callback method withUploadedFiles(List<UploadedFile>).

See examples page.

If you use by default configuration in application.properties:

struts.multipart.parser=jakarta

then you don't need to convert UploadedFile::getContent to File. If you don't use custom parser then just cast it directly. Only StrutsUploadedFile inplemented UploadedFile and it returns File type

File file = (File) uploadedFile.getContent();