====== JavaMailSender ======
  * java email mail sender

===== 첨부파일 =====
  * [[https://www.mkyong.com/spring/spring-sending-e-mail-with-attachment/|Spring – Sending e-mail with attachment]]

<code java>
public class MailMail
{
    private JavaMailSender mailSender;
    private SimpleMailMessage simpleMailMessage;

    public void setSimpleMailMessage(SimpleMailMessage simpleMailMessage) {
        this.simpleMailMessage = simpleMailMessage;
    }

    public void setMailSender(JavaMailSender mailSender) {
        this.mailSender = mailSender;
    }

    public void sendMail(String dear, String content) {

        MimeMessage message = mailSender.createMimeMessage();

        try{
            MimeMessageHelper helper = new MimeMessageHelper(message, true);

            helper.setFrom(simpleMailMessage.getFrom());
            helper.setTo(simpleMailMessage.getTo());
            helper.setSubject(simpleMailMessage.getSubject());
            helper.setText(String.format(
                        simpleMailMessage.getText(), dear, content));

            FileSystemResource file = new FileSystemResource("C:\\log.txt");
            helper.addAttachment(file.getFilename(), file);

        }catch (MessagingException e) {
            throw new MailParseException(e);
        }
        mailSender.send(message);
    }
}
</code>
  * 이미 오픈된 ''InputStream''은 ''ByteArrayDataSource'' 사용<code java>
ByteArrayDataSource attachment = new ByteArrayDataSource(message.getPayload(), "application/octet-stream");
</code>
  * ''Passed-in Resource contains an open stream: invalid argument. JavaMail requires an InputStreamSource that creates a fresh stream for every call.'' 오류 발생
  * JavaMailSender는 InputStream 을 두 번 연다. 한 번은 인코딩을 확인하러, 한 번은 확인한 인코딩으로 인코드 하려고. 따라서 열린 Stream이면 안된다.