using javax.mail api to send emails

SendEmail.java

/**
 * 发送邮件.
 * @param toAddrs
 * @param subject
 * @param content
 * @param files
 */
public static void sendMail(List<String> toAddrs, String subject, String content, List<String> files) {
    if(CollectionUtils.isEmpty(toAddrs)){
        return;
    }
    try {
        Properties props = new Properties();
        // set smtp server
        props.setProperty("mail.transport.protocol", "smtp");
        props.setProperty("mail.smtp.host", SMTP_SERVER);
        props.setProperty("mail.smtp.auth", "true");
//          props.put("mail.debug", "true");

        // get session
        Authenticator auth = new Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(AUTH_USER, AUTH_PASSWORD);
            }
        };
        Session session = Session.getDefaultInstance(props, auth);
//            session.setDebug(true);
        MimeMessage message = new MimeMessage(session);
        message.setFrom(new InternetAddress(SENDER));
        // to list
        InternetAddress[] addresses = new InternetAddress[toAddrs.size()];
        for (int i = 0; i < toAddrs.size(); i++) {
            addresses[i] = new InternetAddress(toAddrs.get(i));
        }
        message.setRecipients(Message.RecipientType.TO, addresses);
        message.setSubject(subject);
        Multipart mp = new MimeMultipart();
        MimeBodyPart mbp = new MimeBodyPart();
        mbp.setContent(content, "text/html; charset=GBK");
        mp.addBodyPart(mbp);
        if (CollectionUtils.isNotEmpty(files)) {
            for (String file : files) {
                if (StringUtils.isBlank(file)) {
                    continue;
                }
                FileDataSource fds = new FileDataSource(file);
                mbp = new MimeBodyPart();
                mbp.setDataHandler(new DataHandler(fds));
                mbp.setFileName(MimeUtility.encodeText(fds.getName(), "GBK", "B"));
                mp.addBodyPart(mbp);
            }
        }
        message.setContent(mp);
        message.setSentDate(new Date());
        message.saveChanges();
        Transport.send(message);
    } catch (Exception e) {
        logger.error("发送邮件失败" + e.toString());
    }
}