在base64中提取带有嵌入式附件的电子邮件正文

Question

作为系统的一部分，我们从Exchange收件箱文件夹中提取邮件。 除了提取电子邮件正文之外，其他所有步骤都进行得很顺利。 保存为HTML的电子邮件正文，但是CIDS（INLINE附件）必须作为Base64保留在HTML文档中。

这怎么可能呢？ 有例子吗？

private void downloadAttachment(Part part, String folderPath) throws Exception {
    String disPosition = part.getDisposition();
    String fileName = part.getFileName();
    String decodedText = null;
    logger.info("Disposition type :: " + disPosition);
    logger.info("Attached File Name :: " + fileName);

    if (disPosition != null && disPosition.equalsIgnoreCase(Part.ATTACHMENT)) {
        logger.info("DisPosition is ATTACHMENT type.");
        File file = new File(folderPath + File.separator + decodedText);
        file.getParentFile().mkdirs();
        saveEmailAttachment(file, part);
    } else if (fileName != null && disPosition == null) {
        logger.info("DisPosition is Null type but file name is valid.  Possibly inline attchment");
        File file = new File(folderPath + File.separator + decodedText);
        file.getParentFile().mkdirs();
        saveEmailAttachment(file, part);
    } else if (fileName == null && disPosition == null) {
        logger.info("DisPosition is Null type but file name is null. It is email body.");
        File file = new File(folderPath + File.separator + "mail.html");
        file.getParentFile().mkdirs();
        saveEmailAttachment(file, part);
    }


}
     protected int saveEmailAttachment(File saveFile, Part part) throws Exception {

    BufferedOutputStream bos = null;
    InputStream is = null;
    int ret = 0, count = 0;
    try {
        bos = new BufferedOutputStream(new FileOutputStream(saveFile));
        part.writeTo(new FileOutputStream(saveFile));

    } finally {
        try {
            if (bos != null) {
                bos.close();
            }
            if (is != null) {
                is.close();
            }
        } catch (IOException ioe) {
            logger.error("Error while closing the stream.", ioe);
        }
    }
    return count;
}