javaMail使用javax.mail自动读取邮件，并下载解析附件，IMAP/POP3协议等

搜索网上各个案例，总结的一套比较全面且行之有效的方法。供大家参考使用！

使用javax.mail自动读取邮件，并下载解析附件，IMAP/POP3协议等！

 

直接上代码如下：

package ***

import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import javax.mail.Address;
import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.NoSuchProviderException;
import javax.mail.Part;
import javax.mail.Session;
import javax.mail.Store;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeUtility;
import javax.mail.search.AndTerm;
import javax.mail.search.ComparisonTerm;
import javax.mail.search.FromStringTerm;
import javax.mail.search.SearchTerm;
import javax.mail.search.SentDateTerm;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Calendar;
import java.util.Date;
import java.util.Properties;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 */
@Component
public class BlacklistCodeTask {


    private static Logger logger = LoggerFactory.getLogger(BlacklistCodeTask.class);

    @Autowired
    private blacklistService blacklistService;



    // 邮箱附件保存路径
    private static String FILE_SAVE_PATH = ConfigProperties.getProperties("blacklist.emailFilePath");
    // 读取的发件人
    private static String fromEmail = ConfigProperties.getProperties("blacklist.fromEmail");
    // 收件服务器 
    private static String hostServer = ConfigProperties.getProperties("blacklist.hostServer");
    private static String protocol = ConfigProperties.getProperties("blacklist.protocol");
    private static String port = ConfigProperties.getProperties("blacklist.port");
    private static String username = ConfigProperties.getProperties("blacklist.username");
    private static String password = ConfigProperties.getProperties("blacklist.password");

    // 执行日期标识
    String dateTimeFlag;
    // 附件名称关键词
    private static String FILE_NAME_FLAG1 = "加黑***明细";
    private static String FILE_NAME_FLAG2 = "加黑";

    // Runtime.getRuntime().availableProcessors()
    public static ExecutorService threadPool = Executors.newFixedThreadPool(1);


    /**
     * 定时任务获取前一天邮件，并解析保存黑端口号码
     */
    public void acquireXinAnEmails() {
        try {
            // 1. 设置连接信息, 生成一个 Session
            // 获取连接
            Session session;
            if ("pop3".equalsIgnoreCase(protocol)) {
                session = Session.getInstance(getPOP3());
//                session = Session.getDefaultInstance(getPOP3());
            } else {
//                session = Session.getDefaultInstance(getIMAP());
                session = Session.getInstance(getIMAP());
            }
            session.setDebug(false);
            // 2. 获取Store, 并连接到服务器
            Store store = session.getStore(protocol);
            store.connect(hostServer, username, password); // POP3服务器的登陆认证
            //
            Folder defaultFolder = store.getDefaultFolder();// 默认父目录
            if (defaultFolder == null) {
                logger.error("服务器不可用！ hostServer:{}", hostServer);
                return;
            }
            //
            Folder folder = defaultFolder.getFolder("INBOX");// 获取收件箱
            folder.open(Folder.READ_WRITE);// 可读邮件,可以删邮件的模式打开目录
            // 取出来邮件数
            logger.info("folder urlName: {}, 共有邮件: {}封, UnreadMessages: {}, NewMessages: {}...", folder.getURLName().toString(),
                    folder.getMessageCount(), folder.getUnreadMessageCount(), folder.getNewMessageCount());
            //
            dateTimeFlag = DateTimeUtil.formatDateTime(new Date(), DateTimeUtil.DATA_FORMAT_yyyyMMdd);
            searchMails(folder);

            // 7. 关闭 Folder 会真正删除邮件, false 不删除
            folder.close(false);
            // 8. 关闭 store, 断开网络连接
            store.close();

        } catch (NoSuchProviderException e) {
            logger.error(e.getMessage(), e);
        } catch (Exception e) {
            logger.error(e.getMessage(), e);
        }
//        // 统一处理下载好的的Excel文件
//        dealAndGetBlacklist();
        
    }

    /**
     * 获取POP3收信配置 995
     *
     * @return
     */
    private Properties getPOP3() {
        Properties props = new Properties();
        props.setProperty("mail.transport.protocol", protocol);
        props.setProperty("mail.pop3.host", hostServer); // 按需要更改
        props.setProperty("mail.pop3.port", port);
        // SSL安全连接参数
        props.setProperty("mail.pop3.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
        props.setProperty("mail.pop3.socketFactory.fallback", "false");
        props.setProperty("mail.pop3.socketFactory.port", port);
        // 解决DecodingException: BASE64Decoder: but only got 0 before padding character (=)
        props.setProperty("mail.mime.base64.ignoreerrors", "true");
        return props;
    }

    /**
     * 获取IMAP收信配置 993
     *
     * @return
     */
    private Properties getIMAP() {
        Properties props = new Properties();
        props.setProperty("mail.transport.protocol", protocol);
        props.setProperty("mail.imap.host", hostServer); // 按需要更改
        props.setProperty("mail.imap.port", port);
        // SSL安全连接参数
        props.setProperty("mail.imap.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
        props.setProperty("mail.imap.socketFactory.fallback", "false");
        props.setProperty("mail.imap.socketFactory.port", port);
        props.setProperty("mail.mime.base64.ignoreerrors", "true");
        return props;
    }


    /**
     * 创建搜索条件，并获取邮件...第二天凌晨10分之后执行，查询前一天零点到今天零点的数据
     *
     * @param folder
     * @throws Exception
     */
    private void searchMails(Folder folder) throws Exception {
        //建立搜索条件继承自SearchTerm，像根据发件人，主题搜索，邮件标记FlagTerm等，
        // FlagTerm ft = new FlagTerm(new Flags(Flags.Flag.SEEN), false); //false代表未读，true代表已读
        // 搜索昨天收到的的所有邮件
        Calendar calendar = Calendar.getInstance();
        calendar.add(Calendar.DAY_OF_MONTH, -1);
        calendar.set(Calendar.HOUR_OF_DAY, 0);
        calendar.set(Calendar.MINUTE, 0);
        calendar.set(Calendar.SECOND, 0);
        Date start = calendar.getTime();
        calendar.setTime(new Date());
        calendar.set(Calendar.HOUR_OF_DAY, 0);
        calendar.set(Calendar.MINUTE, 0);
        calendar.set(Calendar.SECOND, 0);
        Date end = calendar.getTime();
        SearchTerm comparisonTermGe = new SentDateTerm(ComparisonTerm.GE, start);
        SearchTerm comparisonTermLe = new SentDateTerm(ComparisonTerm.LE, end);
        FromStringTerm fromStringTerm = new FromStringTerm(fromEmail);
        SearchTerm andTerm = new AndTerm(new SearchTerm[]{comparisonTermGe, comparisonTermLe, fromStringTerm});
        logger.info("SearchTerm start: {}, end: {}, fromEmail: {}", DateTimeUtil.formatDateTime(start, DateTimeUtil.DATA_FORMAT_yyyy_MM_dd_HH_mm_ss),
                DateTimeUtil.formatDateTime(end, DateTimeUtil.DATA_FORMAT_yyyy_MM_dd_HH_mm_ss), fromEmail);
        //
        Message[] messages = folder.search(andTerm); //根据设置好的条件获取message
        logger.info("search邮件: " + messages.length + "封, SearchTerm:" + andTerm.getClass());
        // FetchProfile fProfile = new FetchProfile(); // 选择邮件的下载模式,
        // fProfile.add(FetchProfile.Item.ENVELOPE); // 根据网速选择不同的模式
        // folder.fetch(messages, fProfile);// 选择性的下载邮件
        // 5. 循环处理每个邮件并实现邮件转为新闻的功能
        for (int i = 0; i < messages.length; i++) {
            // 单个邮件
            logger.info("---第" + i + "邮件开始------------");
            mailReceiver(messages[i]);
            logger.info("---第" + i + "邮件结束------------");
            // 邮件读取备份保存，用来校验
//            messages[i].writeTo(new FileOutputStream(FILE_SAVE_PATH + "pop3Mail_" + messages[i].getMessageNumber() + ".eml"));
        }
    }


    /**
     * 解析邮件
     *
     * @param msg 邮件对象
     * @throws Exception
     */
    private void mailReceiver(Message msg) {
        try {
            // 发件人信息
            Address[] froms = msg.getFrom();
            String mailSubject = transferChinese(msg.getSubject());
            if (froms != null) {
                InternetAddress addr = (InternetAddress) froms[0];
                logger.info("发件人地址:" + addr.getAddress() + ", 发件人显示名:" + transferChinese(addr.getPersonal()));
            } else {
                logger.error("msg.getFrom() is null... subject:" + mailSubject);
            }
            Date sentDate = msg.getSentDate();
            logger.info("邮件主题: {}, sentDate: {}", mailSubject,
                    sentDate == null ? null : DateTimeUtil.formatDateTime(sentDate, DateTimeUtil.DATA_FORMAT_yyyy_MM_dd_HH_mm_ss));

            // getContent() 是获取包裹内容, Part相当于外包装
            Object content = msg.getContent();
            if (content instanceof Multipart) {
                Multipart multipart = (Multipart) content;
                reMultipart(multipart);
            } else if (content instanceof Part) {
                Part part = (Part) content;
                rePart(part);
            } else {
                String contentType = msg.getContentType();
                if (contentType != null && contentType.startsWith("text/html")) {
                    logger.warn("---类型:" + contentType);
                } else {
                    logger.warn("---类型:" + contentType);
                    logger.warn("---内容:" + msg.getContent());
                }
            }
        } catch (Exception e) {
            logger.error(e.getMessage(), e);
        }
    }

    /**
     * 把邮件主题转换为中文.
     *
     * @param strText the str text
     * @return the string
     */
    public String transferChinese(String strText) {
        try {
            if (StringUtils.isBlank(strText)) {
                return null;
            }
            strText = MimeUtility.encodeText(new String(strText.getBytes(),
                    "UTF-8"), "UTF-8", "B");
            strText = MimeUtility.decodeText(strText);
        } catch (Exception e) {
            logger.error(e.getMessage(), e);
        }
        return strText;
    }


    /**
     * @param part 解析内容
     * @throws Exception
     */
    private void rePart(Part part) {
        String tempFilePath = null;
        try {
            // 附件
            if (part.getDisposition() != null) {
                // 邮件附件
                String strFileName = MimeUtility.decodeText(part.getFileName()); //MimeUtility.decodeText解决附件名乱码问题
                logger.info("发现附件: {}, 内容类型: {} ", strFileName, MimeUtility.decodeText(part.getContentType()));
                // 读取附件字节并存储到文件中. xls/xlsx
                String fileType = strFileName.substring(strFileName.lastIndexOf(".") + 1);
                if ((fileType.equals("xlsx") || fileType.equals("xls")) &&
                        (strFileName.contains(FILE_NAME_FLAG1) || strFileName.contains(FILE_NAME_FLAG2))) {
                    InputStream in = part.getInputStream();// 打开附件的输入流
                    tempFilePath = FILE_SAVE_PATH + dateTimeFlag + strFileName;
                    FileOutputStream out = new FileOutputStream(tempFilePath);
                    int data;
                    while ((data = in.read()) != -1) {
                        out.write(data);
                    }
                    in.close();
                    out.close();
                } else {
                    logger.info("not what we need file, discard it: {}", strFileName);
                }
            } else {
                // 邮件内容
                if (part.getContentType().startsWith("text/plain") || part.getContentType().startsWith("Text/Plain")) {
                    logger.info("Content文本内容：" + part.getContent());
                } else if (part.getContentType().startsWith("text/html")) {
//                    logger.info("HTML内容：" + part.getContent());
                    logger.debug("HTML内容，，不记录日志展示。。");
                } else {
                    logger.debug("!其它ContentType:" + part.getContentType() + " ?内容：" + part.getContent());
                }
            }
        } catch (MessagingException e) {
            logger.error(e.getMessage(), e);
        } catch (IOException e) {
            logger.error(e.getMessage(), e);
        } finally {
            // 单个处理黑名单文件，放入线程池处理
            String finalTempFilePath = tempFilePath;
            threadPool.execute(() -> {
                        dealBlacklist(finalTempFilePath);
                    }
            );
        }
    }


    /**
     * @param multipart // 接卸包裹（含所有邮件内容(包裹+正文+附件)）
     * @throws Exception
     */
    private void reMultipart(Multipart multipart) throws Exception {
        logger.debug("Multipart邮件共有" + multipart.getCount() + "部分组成");
        // 依次处理各个部分
        for (int j = 0, n = multipart.getCount(); j < n; j++) {
            Part part = multipart.getBodyPart(j);
            // 解包, 取出 MultiPart的各个部分, 每部分可能是邮件内容, 也可能是另一个小包裹(MultipPart)
            if (part.getContent() instanceof Multipart) {
                logger.debug("部分" + j + "的ContentType: " + part.getContentType() + ", to reMultipart() ");
                Multipart p = (Multipart) part.getContent();// 转成小包裹
                //递归迭代
                reMultipart(p);
            } else {
                logger.debug("部分" + j + "的ContentType: " + part.getContentType() + ", to rePart() ");
                rePart(part);
            }
        }
    }

    /**
     * 单个处理下载好的文件
     *
     * @param tempFilePath
     */
    private void dealBlacklist(String tempFilePath) {
        if (StringUtil.isBlank(tempFilePath)) {
            return;
        }
        logger.info("to deal with blacklist Excel file: {}", tempFilePath);
        blacklistService.dealBlacklist(tempFilePath);

    }


}