<dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-mail</artifactId>
      <version>${spring-boot.version}</version>
  </dependency>

spring:
  mail:
    host: smtp.qq.com
    port: 25
    protocol: smtp
    username: 409835152@qq.com
    password: '******'

@Service
public class EmailQQService {

    @Resource
    private JavaMailSender javaMailSender;

    @Resource
    private MailProperties mailProperties;

    public void sendEmail(Email email){
      SimpleMailMessage simpleMailMessage = new SimpleMailMessage();
      simpleMailMessage.setFrom(mailProperties.getUsername()); //設(shè)置發(fā)送郵件賬號(hào)
      simpleMailMessage.setTo(email.getTo()); //設(shè)置接收郵件的人，可以多個(gè)
      simpleMailMessage.setSubject(email.getSubject()); //設(shè)置發(fā)送郵件的主題
      simpleMailMessage.setText(email.getText()); //設(shè)置發(fā)送郵件的內(nèi)容
      javaMailSender.send(simpleMailMessage);
    }
}

@Service
public class QqEmailService {
    
    public List<Email> receiveEmail() throws MessagingException, IOException {
        Properties properties = configProperties();
        Store store = createStore( properties );
        List<Email> emails = receive(store);
        store.close();
        return emails;
    }

}

private Properties configProperties(){
        // 配置郵件服務(wù)器
        Properties properties = new Properties();
        properties.setProperty("mail.store.protocol", receiveMailProperties.getProtocol());
        properties.setProperty("mail.imap.host", receiveMailProperties.getHost());
        properties.setProperty("mail.imap.port", receiveMailProperties.getPort());
        return properties;
    }

private Store createStore(Properties properties) throws MessagingException {
        // 創(chuàng)建Session實(shí)例對(duì)象
        Session session = Session.getInstance( properties );
        // 創(chuàng)建IMAP協(xié)議的Store對(duì)象
        Store store = session.getStore("imap");
        // 連接郵件服務(wù)器
        store.connect(mailProperties.getUsername(), mailProperties.getPassword());
        return store;
    }

private List<Email> receive(Store store) throws MessagingException, IOException {
        // 獲得收件箱
        Folder folder = store.getFolder("INBOX");
        // 以讀寫(xiě)模式打開(kāi)收件箱
        folder.open(Folder.READ_WRITE);
        // 各狀態(tài)郵件數(shù)量
        System.out.println(String.format("收件箱郵件總數(shù)：%s，其中，新郵件數(shù)：%s，未讀郵件數(shù)：%s，",folder.getMessageCount(), folder.getUnreadMessageCount(), folder.getNewMessageCount()));
        // 獲得收件箱的郵件列表
        Message[] messages = folder.getMessages(folder.getMessageCount()-5, folder.getMessageCount());
        System.out.println("------------------------開(kāi)始解析郵件----------------------------------");
        List<Email> emailList = new ArrayList<>();
        for (Message message : messages) {
            Email email = new Email()
                    .setFrom(Arrays.stream(message.getFrom()).map(address -> ((InternetAddress)address).getAddress()).collect(Collectors.joining()))
                    .setSubject(message.getSubject())
                    .setContentType(message.getContentType())
                    .setSendDate(message.getSentDate())
                    .setReceiveDate(message.getReceivedDate());


            System.out.println(String.format(">>>>> 郵件來(lái)自：%s，主題：%s，接收時(shí)間：%s", email.getFrom(),
                    email.getSubject(),
                    DateFormatUtils.format(email.getReceiveDate(), DateFormatUtils.ISO_8601_EXTENDED_DATETIME_FORMAT.getPattern()))
            );
            email.setEmailContents(resolveMessage(message.getContentType(), message));
            System.out.println(String.format("郵件內(nèi)容：%s" , email.getEmailContents()));
            emailList.add(email);
        }
        // 關(guān)閉資源
        folder.close(false);
        return emailList;
    }

private List<EmailContent> resolveMessage(String contentType, Message message) throws MessagingException, IOException {
        List<EmailContent> emailContents = new ArrayList<>();
        resolveMessageContent( message.getContent(), message, emailContent->{
            emailContents.add(emailContent);
        } );
//        return content.toString();
        return emailContents;
    }

    private void resolveMessageContent(Object content, Object parent, Consumer<EmailContent> emailContentConsumer) throws MessagingException, IOException {
        if( content instanceof String ){
            emailContentConsumer.accept( new EmailContent(EmailContent.Type.TEXT, (String) content) );
        }else if( content instanceof MimeMultipart){
            MimeMultipart multipart = (MimeMultipart) content;
            int count = multipart.getCount(), index = -1;
            while ( count > ++index ){//  0：純文本；1：html內(nèi)容
                BodyPart bodyPart = multipart.getBodyPart(index);
                Object partContent = bodyPart.getContent();
                resolveMessageContent( partContent, bodyPart, emailContentConsumer);
            }
        }else if( content instanceof BASE64DecoderStream){
            File file = new File(((IMAPBodyPart) parent).getFileName());
            ((BASE64DecoderStream) content).transferTo( new FileOutputStream( file ) );
            emailContentConsumer.accept( new EmailContent(EmailContent.Type.FILE, file.getAbsolutePath()) );
        }else {
            System.out.println(">>>>>>>>>>>>>>>> 郵件內(nèi)容類型： "+ content.getClass() );
            emailContentConsumer.accept( new EmailContent(EmailContent.Type.TEXT, content.toString()) );
        }
    }

store.close();