将 Docx4j 文档转换为 PDF 时如何处理临时图片文件

private static final String TEMP_IMAGE_DIR_PATH = "/tmp/images";

public static void convert(WordprocessingMLPackage wordMLPackage, OutputStream output) throws Exception {

    Mapper fontMapper = new BestMatchingMapper();
    wordMLPackage.setFontMapper(fontMapper);

    FOSettings foSettings = new FOSettings(wordMLPackage);
    foSettings.setApacheFopMime("application/pdf");
    foSettings.setImageDirPath(TEMP_IMAGE_DIR_PATH);
    foSettings.setFoDumpFile(null);

    FopFactoryBuilder fopFactoryBuilder = FORendererApacheFOP.getFopFactoryBuilder(foSettings) ;
    FopFactory fopFactory = fopFactoryBuilder.build();

    FOUserAgent foUserAgent = FORendererApacheFOP.getFOUserAgent(foSettings, fopFactory);

    Docx4J.toFO(foSettings, output, Docx4J.FLAG_EXPORT_PREFER_XSL);

    // Clean up, so any ObfuscatedFontPart temp files can be deleted
    if (wordMLPackage.getMainDocumentPart().getFontTablePart()!=null) {
        wordMLPackage.getMainDocumentPart().getFontTablePart().deleteEmbeddedFontTempFiles();
    }
    foSettings = null;
    wordMLPackage = null;

    FileUtils.deleteDirectory(new File(TEMP_IMAGE_DIR_PATH));
}