Java —— 连接邮箱，读取收件箱中的邮件

问题

如何在java程序中连接邮箱，并读取收件箱中的邮件呢？

解决

/**
* @param protocol 邮箱使用的协议
* @param port 端口
* @param host host
* @param user 用户名
* @param psw 密码
*/
public void emailDemmo(@RequestParam String protocol,
                     @RequestParam String port,
                     @RequestParam String host,
                     @RequestParam String user,
                     @RequestParam String psw) {
        Properties props = new Properties();
        //pop3
        props.setProperty("mail.store.protocol", protocol);
        props.setProperty("mail.pop3.port", port);
        props.setProperty("mail.pop3.host", host);
        Folder folder = null;
        Store store = null;
        try {
            // 创建Session实例对象
            Session session = Session.getInstance(props);
            store = session.getStore(protocol);
            store.connect(user, psw);

            // 获得收件箱
            folder = store.getFolder("INBOX");
            //打开收件箱
            folder.open(Folder.READ_WRITE);
            log.debug("收件箱已打开");

            Message[] messages = folder.getMessages();
            for (Message message : messages) {
                //逐个处理邮件
            }
        } catch (MessagingException | UnsupportedEncodingException e) {
            log.error("初始化邮箱失败！！！", e);
        } finally {
            try {
                if (folder != null) {
                    folder.close(true);
                }
            } catch (MessagingException e) {
                log.error("文件目录关闭失败！！！", e);
            }
            try {
                if (store != null) {
                    store.close();
                }
            } catch (MessagingException e) {
                log.error("邮箱连接关闭失败！！！", e);
            }
        }
    }