java接收邮件

public  void receive(){
    try {
        Properties props = new Properties();
        props.setProperty("mail.store.protocol", "imap");       // 协议
        props.setProperty("mail.pop3.port", "993");             // 端口
        props.setProperty("mail.pop3.host", "imap.exmail.qq.com");    // pop3服务器

        // 创建Session实例对象
        Session session = Session.getInstance(props);
        Store store = session.getStore();
        store.connect("imap.exmail.qq.com","[email protected]", "FQzQwGj8YkgwvzvHtNGFBrpN");

        // 获得收件箱
        Folder folder = store.getFolder("INBOX");
        folder.open(Folder.READ_ONLY);
    /* Folder.READ_ONLY：只读权限
     * Folder.READ_WRITE：可读可写（可以修改邮件的状态）
     */
        log.info("未读邮件数: " + folder.getUnreadMessageCount());
        log.info("新邮件: " + folder.getNewMessageCount());
        log.info("邮件总数: " + folder.getMessageCount());
        Message[] messages = folder.getMessages();
        List<String> sign = new ArrayList<>();
        for (Message m:messages) {
            Flags flags = m.getFlags();
            //已读
            if(flags.toString().contains("FLAGS@20")){
                log.info("已读");
            }//未读
            else if(flags.toString().contains("FLAGS@0")){
                //设置已读
                //m.setFlag(Flags.Flag.SEEN,true);
                if(m.getSubject().substring(0,3).equals("Re:")){
                    String l = m.getSubject();
                    //把未读的时间戳放入sign等待修改状态
                    sign.add(l.substring(l.length()-13,l.length()));
                }else{
                    log.info("非回执邮件");
                }
            }
        }
        emailRecordRepostory.updateBySign(sign);
        log.info("未读邮件数",folder.getUnreadMessageCount());

    } catch (MessagingException e) {
        e.printStackTrace();
    }
}