@Override
    public File createTempFile(String prefix, String suffix) throws IOException {
        // Identify and create our temp dir, if needed
        createPOIFilesDirectory();

        // Generate a unique new filename
        File newFile = Files.createTempFile(dir.toPath(), prefix, suffix).toFile();

        // Set the delete on exit flag, but only when explicitly disabled
        if (System.getProperty(DELETE_FILES_ON_EXIT) != null) {
            newFile.deleteOnExit();
        }

        // All done
        return newFile;
    }
Creates the strategy allowing to set the

@param dir The directory where the temporary files will be created (<code>null</code> to use the default
           directory).
@see Files#createTempFile(Path, String, String, FileAttribute[])
fastexcel-core/src/main/java/cn/idev/excel/util/EasyExcelTempFileCreationStrategy.java