无法从邮件attachmnet读取XLSX文件内容以存储本地驱动器

Question

以下是我们使用的Java代码：

String contentType = message.getContentType();
String attachFiles = "";
// String saveDirectory = (String) resources.get(SystemRqstAppConstants.WebConstants.CUSTOMERITEMVENDORPO_PATH);
String saveDirectory ="D:/ResumeFiles/";
List<String> errorsList= null;
String messageContent = "";
logger.info(":::::Timecards Auto Update before Attchments:::::");
if (contentType.contains("multipart")) {
    // content may contain attachments
    String client="";
    if(subject.contains("xxxx") || subject.contains("xxxx") || subject.contains("xxxx"))
        client="xxxx";
    else if(subject.contains("xxx") || subject.contains("xxx") || subject.contains("xxx"))
        client="xxx";                                                   
    logger.info("Timecards Auto Update client name: "+client);
    Multipart multiPart = (Multipart) message.getContent();
    int numberOfParts = multiPart.getCount();
    for (int partCount = 0; partCount < numberOfParts; partCount++) {
        MimeBodyPart part = (MimeBodyPart) multiPart.getBodyPart(partCount);
        if (Part.ATTACHMENT.equalsIgnoreCase(part.getDisposition())) {
            // this part is attachment
            fileName = part.getFileName();
            attachFiles += fileName + ", ";
            saveDirectory = saveDirectory+client+"/";
            File folder = new File(saveDirectory);
            if(!folder.exists())
                folder.mkdir();
            String destFilePath = saveDirectory+fileName;
            logger.info("Timecards Auto Update destFilePath: "+destFilePath);
             FileOutputStream fileOutStream = new FileOutputStream(destFilePath);

            byte abyte0[] = new byte[4096];
            int length=0; 
            input = part.getInputStream();
            DataInputStream in = new DataInputStream(input);
            while ((in != null) && ((length = in.read(abyte0)) != -1)){
                 fileOutStream.write(abyte0, 0, length);
            }
            input.close();
            in.close();
            // my_xlsx_workbook.write(fileOutStream);
            fileOutStream.flush();
            fileOutStream.close();
        }   
    }
}

提前致谢。