如何使用spring发送带有附件的电子邮件使用InputStream？

    helper.addAttachment(\"attachement\",
    new ByteArrayResource(IOUtils.toByteArray(inputStream)));

JavaMailSenderImpl sender = new JavaMailSenderImpl();
sender.setHost(\"mail.host.com\");

MimeMessage message = sender.createMimeMessage();

// use the true flag to indicate you need a multipart message
MimeMessageHelper helper = new MimeMessageHelper(message, true);
helper.setTo(\"test@host.com\");

helper.setText(\"Check out this image!\");

// let\'s attach the infamous windows Sample file (this time copied to c:/)
FileSystemResource file = new FileSystemResource(new File(\"c:/Sample.jpg\"));
helper.addAttachment(\"CoolImage.jpg\", file);

sender.send(message);

InputStreamSource iss = new InputStreamSource() {
    @Override
    public InputStream getInputStream() throws IOException {
        // provide fresh InputStream
        return new FileInputStream(\"c:\\\\a.txt\");
    }
}
MimeMessageHelper message = new MimeMessageHelper(mimeMessage, true, \"UTF-8\");
message.addAttachment(\"attachment\", iss);

ByteArrayDataSource source = new ByteArrayDataSource(\"file name\", \"contentType\", inlineFileObjectCreated.getBytes() );

                JavaMailSender mailSender = (JavaMailSender) ServicesHome.getService(\"javaMailSender\");
                MimeMessage mimeMessage = mailSender.createMimeMessage();
                MimeMessageHelper mimeMessageHelper = new MimeMessageHelper(mimeMessage, true);
                mimeMessageHelper.setTo(toArray);           
                mimeMessageHelper.setSubject(\"\");
                mimeMessageHelper.setText(\"\");
                mimeMessageHelper.addAttachment(\"filename\", source);
                mailSender.send(mimeMessageHelper.getMimeMessage());

import javax.activation.DataSource;

    public class ByteArrayDataSource implements DataSource {
        byte[] bytes;
        String contentType;
        String name;

        public ByteArrayDataSource( String name, String contentType, byte[] bytes ) {
          this.name = name;
          this.bytes = bytes;
          this.contentType = contentType;
        }

        public String getContentType() {
          return contentType;
        }

        public InputStream getInputStream() {
          return new ByteArrayInputStream(bytes);
        }

        public String getName() {
          return name;
        }

        public OutputStream getOutputStream() throws IOException {
          throw new FileNotFoundException();
        }
      }

public void send() throws IOException, MessagingException {
    final ByteArrayOutputStream stream = createInMemoryDocument(\"body\");
    final InputStreamSource attachment = new ByteArrayResource(stream.toByteArray());
    final MimeMessage message = javaMailSender.createMimeMessage();
    final MimeMessageHelper helper = new MimeMessageHelper(message, true);
    helper.setSubject(\"subject\");
    helper.setFrom(\"from@from.com\");
    helper.setTo(\"to@to.com\");
    helper.setReplyTo(\"replyTo@replyTo.com\");
    helper.setText(\"stub\", false);
    helper.addAttachment(\"document.txt\", attachment);
    javaMailSender.send(message);
}

public void send() throws IOException, MessagingException {
        final ByteArrayOutputStream document = createInMemoryDocument(\"body\");
        final InputStream inputStream = new ByteArrayInputStream(document.toByteArray());
        final DataSource attachment = new ByteArrayDataSource(inputStream, \"application/octet-stream\");
        final MimeMessage message = javaMailSender.createMimeMessage();
        final MimeMessageHelper helper = new MimeMessageHelper(message, true);
        helper.setSubject(\"subject\");
        helper.setFrom(\"from@from.com\");
        helper.setTo(\"to@to.com\");
        helper.setReplyTo(\"replyTo@replyTo.com\");
        helper.setText(\"stub\", false);
        helper.addAttachment(\"document.txt\", attachment);
        javaMailSender.send(message);
    }

isOpen()

MimeMessageHelper#addAttacment()

public void addAttachment(String attachmentFilename, InputStreamSource inputStreamSource, String contentType) {
    //...
    if (inputStreamSource instanceof Resource && ((Resource) inputStreamSource).isOpen()) {
        throw new IllegalArgumentException(
        \"Passed-in Resource contains an open stream: invalid argument. \" +
        \"JavaMail requires an InputStreamSource that creates a fresh stream for every call.\");
    }
    //...
}

InputStreamResource#isOpen()

true

public class InputStreamResource extends AbstractResource {
   //...
   @Override
   public boolean isOpen() {
      return true;
   }
   //...
}