spring如何使用java mail sender发送带有字节数组的附件的邮件？

Question

我想使用java mail sender发送电子邮件。我有字节数组，我应该作为邮件附件发送。我已经尝试了多种方法，但即将到来的附件不是可读的格式。它以字节的形式出现。下面是我尝试过的代码

public void sendMailWithAttachments(EmailContent emailContent,
            byte[] attachment) {
        try{
            MimeMessage mimeMessage = emailSender.createMimeMessage();
            MimeMessageHelper mimeMessageHelper = new 
             MimeMessageHelper(mimeMessage, true);

            mimeMessageHelper.setTo(emailContent.getTo());
            mimeMessageHelper.setFrom(emailContent.getFrom());
            mimeMessageHelper.setCc(emailContent.getCc());
            mimeMessageHelper.setSubject(emailContent.getSubject());


                final InputStreamSource attachmentSource = new ByteArrayResource(attachment);
                DataSource dataSource = new ByteArrayDataSource(attachment, "application/pdf");
                mimeMessageHelper.addAttachment("testattachment", dataSource);



            emailSender.send(mimeMessageHelper.getMimeMessage());
            emailContent.setStatus(true);
        }catch(Exception e){    
            e.printstacktrace
        }