发送邮件带附件，邀请邮件加入日历

1、发送邮件带附件

/**
*@param fileName 附件文件名
*@param outputStream 附件的输出流
*@param contentType “application/vnd.ms-excel;charset=UTF-8”这是excel附件，其他附件还要稍微改动下
**/
public Result sendMailWithAttachment(String toEmails, String title, String textContent,
                                         ByteArrayOutputStream outputStream,String fileName,String contentType) throws Exception {
        List emailList = Splitter.on(Constant.COMMA).omitEmptyStrings().trimResults().splitToList(toEmails);

        Properties props = new Properties();
        // 开启debug调试
        props.setProperty("mail.debug", "true");
        // 发送服务器需要身份验证
        props.setProperty("mail.smtp.auth", "true");
        // 设置邮件服务器主机名
        props.setProperty("mail.host", “smtp.exmail.qq.com”);
        // 发送邮件协议名称
        props.setProperty("mail.transport.protocol", “smtp”);
        // 设置端口号
        props.setProperty("mail.smtp.port", "465");
        //使用SSL，企业邮箱必需！开启安全协议
        props.put("mail.smtp.ssl.enable", "true");
        props.put("mail.smtp.socketFactory.port", Integer.toString(465));
        props.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
        props.put("mail.smtp.socketFactory.fallback", "true");

        // 设置环境信息
        Session session = Session.getInstance(props);

        MimeMessage message = new MimeMessage(session);
        message.setFrom(new InternetAddress(inviteMailSenderMail, inviteMailSenderMailName, encode));
        for (String toEmailItem : emailList) {
            message.addRecipient(MimeMessage.RecipientType.TO, new InternetAddress(toEmailItem, toEmailItem, encode));
        }
        message.setSubject(title, "UTF-8");
        MimeMultipart multipart = new MimeMultipart();


        // 5. Content: 邮件正文（可以使用html标签）
        if(StringUtils.isNotBlank(textContent)){
            MimeBodyPart text = new MimeBodyPart();
            text.setText(textContent);
            multipart.addBodyPart(text);
        }

        //附件
        MimeBodyPart attach = new MimeBodyPart();
        DataHandler dataHandler2 = new DataHandler(new ByteArrayDataSource(outputStream.toByteArray(),contentType));
        attach.setDataHandler(dataHandler2);
        attach.setFileName(fileName);
        multipart.addBodyPart(attach);

        message.saveChanges();
        message.setContent(multipart);

        // 6. 设置显示的发件时间
        message.setSentDate(new Date());

        // 7. 保存前面的设置
        message.saveChanges();

        Transport transport = session.getTransport(smptProtocal);
        // 连接邮件服务器
        transport.connect(SenderMail, SecurityPwd);//邮箱账号，密码
        // 发送邮件
        Address[] addressArray = new Address[emailList.size()];
        for (int i = 0; i < emailList.size(); i++) {
            addressArray[i] = new InternetAddress(emailList.get(i));
        }
        transport.sendMessage(message, addressArray);
        // 关闭连接
        transport.close();

        return Result.success();
    }

2、发送邀请邮件，并加入日历

public Result sendMail(String toEmails, String title, String textContent, MailBean mailBean) throws Exception {
        List emailList = Splitter.on(Constant.COMMA).omitEmptyStrings().trimResults().splitToList(toEmails);

        Properties props = new Properties();
        // 开启debug调试
        props.setProperty("mail.debug", "true");
        // 发送服务器需要身份验证
        props.setProperty("mail.smtp.auth", "true");
        // 设置邮件服务器主机名
         props.setProperty("mail.host", “smtp.exmail.qq.com”);
        // 发送邮件协议名称
        props.setProperty("mail.transport.protocol", “smtp”);
        // 设置端口号
        props.setProperty("mail.smtp.port", "465");
        //使用SSL，企业邮箱必需！开启安全协议
        props.put("mail.smtp.ssl.enable", "true");
        props.put("mail.smtp.socketFactory.port", Integer.toString(465));
        props.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
        props.put("mail.smtp.socketFactory.fallback", "true");

        // 设置环境信息
        Session session = Session.getInstance(props);

        MimeMessage message = new MimeMessage(session);
        message.setFrom(new InternetAddress(inviteMailSenderMail, inviteMailSenderMailName, encode));
        for (String toEmailItem : emailList) {
            message.addRecipient(MimeMessage.RecipientType.TO, new InternetAddress(toEmailItem, toEmailItem, encode));
        }
        message.setSubject(title, "UTF-8");
        MimeMultipart multipart = new MimeMultipart();

        // 5. Content: 邮件正文（可以使用html标签）
        MimeBodyPart text = new MimeBodyPart();
        text.setText(textContent);
        multipart.addBodyPart(text);

        //vCalendar报文
        Date utcStart = new Date(mailBean.getStartTime().getTime()-8*3600*1000);//转UTC时间
        Date utcEndd = new Date(mail.getEndTime().getTime()-8*3600*1000);//转UTC时间
        String utcStartStr14 = DateUtils.format(utcStart, DateFormatPattern.PATTERN_14);
        String utcEndStr14 = DateUtils.format(utcEndd, DateFormatPattern.PATTERN_14);
        StringBuffer buffer = new StringBuffer().append("BEGIN:VCALENDAR\n")
                .append("PRODID:-//Microsoft Corporation//Outlook 9.0 MIMEDIR//EN\n")
                .append("VERSION:2.0\n")
                .append("METHOD:REQUEST\n")
                .append("BEGIN:VEVENT\n")
                .append("SEQUENCE:1\n");
        for (String toEmailItem : emailList) {
            buffer.append("ATTENDEE;ROLE=REQ-PARTICIPANT;RSVP=TRUE:MAILTO:" + toEmailItem + "\n");
        }
        buffer.append("ORGANIZER:MAILTO:" + inviteMailSenderMail + "\n")
                .append("DTSTART:"+utcStartStr14.substring(0,8)+"T"+utcStartStr14.substring(8,14)+"Z\n") //结尾Z表示UTC时间
                .append("DTEND:"+utcEndStr14.substring(0,8)+"T"+utcEndStr14.substring(8,14)+"Z\n")
                .append("LOCATION:"+mailBean.getLocation()+"\n")
                .append("UID:" + UUID.randomUUID().toString() + "\n") //如果id相同的话，outlook会认为是同一个会议请求，所以使用uuid。
                .append("CATEGORIES:SuccessCentral Reminder\n")
                .append("DESCRIPTION:This the description of the meeting.
asd;flkjasdpfi\n\n")
                .append("SUMMARY:"+mailBean.getSubject()+"\n" + "PRIORITY:5\n")
                .append("CLASS:PUBLIC\n" + "BEGIN:VALARM\n")
                .append("TRIGGER:-PT15M\n" + "ACTION:DISPLAY\n")
                .append("DESCRIPTION:Reminder\n" + "END:VALARM\n")
                .append("END:VEVENT\n" + "END:VCALENDAR");
        BodyPart messageBodyPart = new MimeBodyPart();
        // 测试下来如果不这么转换的话，会以纯文本的形式发送过去，
        //如果没有method=REQUEST;charset=\"UTF-8\"，outlook会议附件的形式存在，而不是直接打开就是一个会议请求
        messageBodyPart.setDataHandler(new DataHandler(new ByteArrayDataSource(buffer.toString(), "text/calendar;method=REQUEST;charset=\"UTF-8\"")));
        multipart.addBodyPart(messageBodyPart);

        message.saveChanges();
        message.setContent(multipart);

        // 6. 设置显示的发件时间
        message.setSentDate(new Date());

        // 7. 保存前面的设置
        message.saveChanges();

        Transport transport = session.getTransport(smptProtocal);
        // 连接邮件服务器
        transport.connect(SenderMail, SecurityPwd);//邮箱账号，密码
        // 发送邮件
        Address[] addressArray = new Address[emailList.size()];
        for (int i = 0; i < emailList.size(); i++) {
            addressArray[i] = new InternetAddress(emailList.get(i));
        }
        transport.sendMessage(message, addressArray);
        // 关闭连接
        transport.close();
        return Result.success();
    }

注意以上是发送邀请邮件，并加入日历，如果需要更新这个日历信息，那么请求参数中的UID参数需要是同一个，且SEQUENCE参数要大于最开始的值。比如上文用的是1，那么第一次更新要改成2，第二次更新要改成3。

如果要取消该邀请邮件，那么METHOD参数要改成CANCEL，UID参数要保持同一个，SEQUENCE参数同样也要增加，比如上文已经更新两次，sequence变成3了，那么取消的时候要变成4