Java imap邮件接收与解析

Properties props = new Properties();
props.setProperty("mail.transport.protocol", "imap"); // 使用的协议, imap | pop3
props.setProperty("mail.imap.host", "smtp.qq.com"); // 邮箱的收件服务器地址

// 获取连接
Session session = Session.getDefaultInstance(props);
session.setDebug(false);

IMAPStore store = (IMAPStore) session.getStore(protocol);
store.connect(emailboxServer, username, authCode); // imap服务器的登录认证, 邮箱账号用户名，授权码
IMAPFolder inbox = (IMAPFolder) store.getFolder("INBOX");
inbox.open(Folder.READ_WRITE);
Message[] messages = inbox.getMessages();

for (Message message : messages) {
    IMAPMessage imapMessage = (IMAPMessage) message;
    Flags flags = imapMessage.getFlags();
    if (flags.contains(Flags.Flag.SEEN)) {
        continue;
    }

    CustomerEmail email = new CustomerEmail();
    email.setEmailId(inbox.getUID(imapMessage)); // 邮件唯一标识
    email.setDeliveryDate(format.format(imapMessage.getSentDate())); // 发件日期
    String subject = imapMessage.getSubject(); // 主题
    email.setSubject(subject);
    InternetAddress from = (InternetAddress) imapMessage.getFrom()[0]; // 发件人
    email.setFrom(from.getAddress());
    InternetAddress to = (InternetAddress) imapMessage.getReplyTo()[0]; // 收件人
    email.setTo(to.getAddress());
    if (message.isMimeType("TEXT/*")) { // 仅包含正文的简单邮件
        System.out.println("邮件正文: " + message.getContent());
    } else {
        parseMessage((MimeMultipart) message.getContent(), email); // 解析稍复杂邮件
    }
}

/**
 * 解析邮件
 */
public static void parseMessage (MimeMultipart part, CustomerEmail email) throws MessagingException, IOException {
    byte[] bytes = new byte[1024];
    ByteArrayOutputStream outStream = new ByteArrayOutputStream();

    for (int i = 0; i < part.getCount(); i++) {
        BodyPart body = part.getBodyPart(i);
        if (body.isMimeType("text/html")) {
            System.out.println("html格式正文: " + (String) body.getContent());
        } else if (body.isMimeType("text/plain")) {
            System.out.println("纯文本格式正文: " + (String) body.getContent());
        } else if (body.isMimeType("multipart/*")) {
            MimeMultipart multipart = (MimeMultipart) body.getContent();
            parseMessage(multipart, email);
        } else { // 附件
            InputStream inputStream = body.getDataHandler().getInputStream();
            int len = 0;
            while( (len = inputStream.read(bytes)) != -1 ){
                outStream.write(bytes, 0, len);
            }
            inputStream.close();
            byte[] data = outStream.toByteArray();
            String fileName = body.getFileName();
            File tempFile = new File(FileUtils.getTempDirectoryPath() + File.separator + System.currentTimeMillis() + fileName );
            FileOutputStream fileOutputStream = new FileOutputStream(tempFile);
            fileOutputStream.write(data);
            fileOutputStream.close();
            System.out.println("邮件附件本地路径: " + tempFile.getAbsolutePath());
        }
    }
}