/**
 * 邮件发送
 * @param message 邮件内容
 * @param to 收件人邮箱
 * @param attachment 附件
 */
public static void sendEmail(String message, String to, File attachment) throws Exception {
    //设置邮件会话参数
    Properties props = new Properties();
    //邮箱的发送服务器地址
    props.setProperty("mail.smtp.host", MAIL_HOST);
    props.setProperty("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
    props.setProperty("mail.smtp.socketFactory.fallback", "false");
    props.put("mail.smtp.ssl.enable", "true");
    //邮箱发送服务器端口,这里设置为465端口
    props.setProperty("mail.smtp.port", "465");
    props.setProperty("mail.smtp.socketFactory.port", "465");
    props.put("mail.smtp.auth", "true");
    //获取到邮箱会话,利用匿名内部类的方式,将发送者邮箱用户名和密码授权给jvm
    Session session = Session.getDefaultInstance(props, new Authenticator() {
        @Override
        protected PasswordAuthentication getPasswordAuthentication() {
            return new PasswordAuthentication(MAIL_USER_NAME, MAIL_AUTH_CODE);
        }
    });
    // 开启调试，生产不开启
    session.setDebug(true);
    Multipart multipart = new MimeMultipart();
    BodyPart contentPart = new MimeBodyPart();
    //contentPart.setContent(message, "text/html;charset=UTF-8");
    contentPart.setText(message);
    multipart.addBodyPart(contentPart);
    if (attachment != null) {
        BodyPart attachmentBodyPart = new MimeBodyPart();
        DataSource source = new FileDataSource(attachment);
        attachmentBodyPart.setDataHandler(new DataHandler(source));
        //MimeUtility.encodeWord可以避免附件文件名乱码
        attachmentBodyPart.setFileName(MimeUtility.encodeWord(attachment.getName()));
        multipart.addBodyPart(attachmentBodyPart);
    }
    //通过会话,得到一个邮件,用于发送
    Message msg = new MimeMessage(session);
    //设置发件人
    msg.setFrom(new InternetAddress(MAIL_USER_NAME));
    //设置收件人,to为收件人,cc为抄送,bcc为密送
    msg.setRecipients(Message.RecipientType.TO, InternetAddress.parse(to, false));
    // msg.setRecipients(Message.RecipientType.CC, InternetAddress.parse(to, false));
    // msg.setRecipients(Message.RecipientType.BCC, InternetAddress.parse(to, false));
    msg.setSubject("我是主题");
    //设置邮件消息
    msg.setContent(multipart);
    //设置发送的日期
    msg.setSentDate(new Date());
    //调用Transport的send方法去发送邮件
    Transport.send(msg);
}