是否可以使用javax.mail发送电子邮件并使用“现有”InputStream作为电子邮件附件内容？目前我正在构建如下电子邮件消息:finalMimeMessagemessage=newMimeMessage(session);message.setFrom(newInternetAddress(from));message.addRecipient(Message.RecipientType.TO,newInternetAddress(to));message.setSubject("Subjectline");finalMultipartmultipartContent=newM