/**
 * 添加附件
 * @param filePath 文件路径
 * @throws MessagingException
 */
public void addAttachment(String filePath) throws MessagingException{
    FileDataSource fileDataSource = new FileDataSource(new File(filePath));
    DataHandler dataHandler = new DataHandler(fileDataSource);
    MimeBodyPart mimeBodyPart = new MimeBodyPart();
    mimeBodyPart.setDataHandler(dataHandler);
    mimeBodyPart.setFileName(fileDataSource.getName());
    this.multipart.addBodyPart(mimeBodyPart);
}
在mainactivity中的代码是
sender.addAttachment("/storage/emulated/0/ggg.jpg");