Java 解析邮箱中的邮件信息保存入库

我们在工作中常常遇到这样的场景：
获取一些其他平台的业务数据，是通过邮件的方式来进行获取的，其他平台通过发送邮件以Excel附件的形式，传输到公司邮箱服务器；我们接收数据是读取服务器中的相关邮件并进行解析，拿到附件，然后通过解析附件Excel的方式，把业务数据落库，后面进行一些列的业务数据处理。

下面摘录了系统相关功能的部分代码分享给大家，大家可以根据工具类进行相关业务逻辑的改造。

大概流程如下：

解析邮件工具类：

MailUtils.java

package com.xxkfz.simplememory.mail;


import com.google.common.collect.Lists;
import lombok.SneakyThrows;
import lombok.extern.slf4j.Slf4j;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.*;

import javax.mail.Address;
import javax.mail.BodyPart;
import javax.mail.Flags;
import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.Part;
import javax.mail.Session;
import javax.mail.Store;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;
import javax.mail.internet.MimeUtility;

/**
 * 使用POP3协议接收邮件
 */
@Slf4j
public class MailUtils{

    public static void main(String[] args) throws Exception {
        DateFormat fmt = new SimpleDateFormat("yyyy-MM-dd");
        String start = "2024-01-01";
        String end = "2024-01-23";

        Date startDate = fmt.parse(start);
        Date endDate = fmt.parse(end);

        // 获取邮件信息
        List<EmailEntity> emailList = getEmailList(startDate, endDate);

    }

    /**
     * 获取邮件信息
     */
    public static List<EmailEntity> getEmailList(Date sendStartDate, Date sendEndDate) throws Exception {
        // 准备连接服务器的会话信息
        Properties props = new Properties();
        // 协议
        props.setProperty("mail.store.protocol", "pop3");   
        // 端口     
        props.setProperty("mail.pop3.port", "110");      
        // pop3服务器          
        props.setProperty("mail.pop3.host", "pop.163.com");    

        // 创建Session实例对象
        Session session = Session.getInstance(props);
        Store store = session.getStore("pop3");
        store.connect("test123@163.com", "xxxxxxxxxxxx");

        // 获得收件箱
        Folder folder = store.getFolder("INBOX");
        /* Folder.READ_ONLY：只读权限
         * Folder.READ_WRITE：可读可写（可以修改邮件的状态）
         */
        folder.open(Folder.READ_WRITE);    //打开收件箱

        // 由于POP3协议无法获知邮件的状态,所以getUnreadMessageCount得到的是收件箱的邮件总数
        System.out.println("未读邮件数: " + folder.getUnreadMessageCount());
        // 由于POP3协议无法获知邮件的状态,所以下面得到的结果始终都是为0
        System.out.println("删除邮件数: " + folder.getDeletedMessageCount());
        System.out.println("新邮件: " + folder.getNewMessageCount());
        // 获得收件箱中的邮件总数
        System.out.println("邮件总数: " + folder.getMessageCount());
        // 获取邮件
        Message[] messages = getEmail(folder, sendStartDate, sendEndDate);
        log.error("共有：{}封邮件", messages.length);
        // 解析邮件
        List<EmailEntity> resList = Lists.newArrayList();
        parseMail(resList, messages);
        //释放资源
        folder.close(true);
        store.close();
        return resList;
    }

    /**
     * 获取邮件列表
     *
     * @param folder
     * @param sendStartDate
     * @param sendEndDate
     * @return
     */
    private static Message[] getEmail(Folder folder, Date sendStartDate, Date sendEndDate) throws MessagingException {
        Message[] messages;
        int messageCount = folder.getMessageCount();
        if ((sendStartDate == null) && (sendEndDate == null)) {
            // 获取最后一封邮件
            messages = folder.getMessages(messageCount, messageCount);
        } else {
            // 获取所有邮件
            Message[] allMessages = folder.getMessages();
            messages = Arrays.stream(allMessages).filter(m -> {
                try {
                    return betweenDate(m, sendStartDate, sendEndDate);
                } catch (MessagingException e) {
                    e.printStackTrace();
                }
                return false;
            }).toArray(Message[]::new);
        }
        return messages;
    }

    /**
     * 日期过滤
     *
     * @param message
     * @param start
     * @param end
     * @return
     * @throws MessagingException
     */
    private static boolean betweenDate(Message message, Date start, Date end) throws MessagingException {
        Date sentDate = message.getSentDate();
        if (Objects.isNull(sentDate)) {
            log.error("sentDate is null {}", message.getSubject());
            return false;
        }
        return sentDate.before(end) && sentDate.after(start) || sentDate.equals(start);
    }


    /**
     * 解析邮件
     *
     * @param messages 要解析的邮件列表
     */
    public static void parseMail(List<EmailEntity> emailEntities, Message... messages) throws MessagingException, IOException {
        if (messages == null || messages.length < 1) throw new MessagingException("未找到要解析的邮件!");
        // 解析所有邮件
        for (int i = 0, count = messages.length; i < count; i++) {
            EmailEntity emailEntity = new EmailEntity();
            MimeMessage msg = (MimeMessage) messages[i];
            String messageID = msg.getMessageID();
            System.err.println("messageID = " + messageID);
            System.out.println("主题: " + getSubject(msg));
            System.out.println("发件人: " + getFrom(msg));
            System.out.println("收件人：" + getReceiveAddress(msg, null));
            System.out.println("发送时间：" + getSentDate(msg, null));
            System.out.println("接收时间：" + getReceiveDate(msg, null));
            System.out.println("是否已读：" + isSeen(msg));
            System.out.println("邮件优先级：" + getPriority(msg));
            System.out.println("是否需要回执：" + isReplySign(msg));
            System.out.println("邮件大小：" + msg.getSize() * 1024 + "kb");
            boolean isContainerAttachment = isContainAttachment(msg);
            System.out.println("是否包含附件：" + isContainerAttachment);
            // 包含附件，进行附件的上传
            if (isContainerAttachment) {
                // 设置上传的路径
                saveAttachment(msg, "E:\\mail\\" + msg.getSubject() + "_");
            }

            // 获取邮件内容
            StringBuffer content = new StringBuffer(30);
            getMailTextContent(msg, content);
            System.out.println("文件内容：" + content);
        }
    }

    /**
     * 获得邮件主题
     *
     * @param msg 邮件内容
     * @return 解码后的邮件主题
     */
    public static String getSubject(MimeMessage msg) throws UnsupportedEncodingException, MessagingException {
        return MimeUtility.decodeText(msg.getSubject());
    }

    /**
     * 获得邮件发件人
     *
     * @param msg 邮件内容
     * @return 姓名 <Email地址>
     * @throws MessagingException
     * @throws UnsupportedEncodingException
     */
    public static String getFrom(MimeMessage msg) throws MessagingException, UnsupportedEncodingException {
        String from = "";
        Address[] froms = msg.getFrom();
        if (froms.length < 1) throw new MessagingException("没有发件人!");

        InternetAddress address = (InternetAddress) froms[0];
        String person = address.getPersonal();
        if (person != null) {
            person = MimeUtility.decodeText(person) + " ";
        } else {
            person = "";
        }
        from = person + "<" + address.getAddress() + ">";

        return from;
    }

    /**
     * 根据收件人类型，获取邮件收件人、抄送和密送地址。如果收件人类型为空，则获得所有的收件人
     * <p>Message.RecipientType.TO  收件人</p>
     * <p>Message.RecipientType.CC  抄送</p>
     * <p>Message.RecipientType.BCC 密送</p>
     *
     * @param msg  邮件内容
     * @param type 收件人类型
     * @return 收件人1 <邮件地址1>, 收件人2 <邮件地址2>, ...
     * @throws MessagingException
     */
    public static String getReceiveAddress(MimeMessage msg, Message.RecipientType type) throws MessagingException {
        StringBuffer receiveAddress = new StringBuffer();
        Address[] addresss = null;
        if (type == null) {
            addresss = msg.getAllRecipients();
        } else {
            addresss = msg.getRecipients(type);
        }

        if (addresss == null || addresss.length < 1) throw new MessagingException("没有收件人!");
        for (Address address : addresss) {
            InternetAddress internetAddress = (InternetAddress) address;
            receiveAddress.append(internetAddress.toUnicodeString()).append(",");
        }

        receiveAddress.deleteCharAt(receiveAddress.length() - 1);    //删除最后一个逗号

        return receiveAddress.toString();
    }

    /**
     * 获得邮件发送时间
     *
     * @param msg 邮件内容
     * @return yyyy年mm月dd日 星期X HH:mm
     * @throws MessagingException
     */
    public static String getSentDate(MimeMessage msg, String pattern) throws MessagingException {
        Date sentDate = msg.getSentDate();
        if (sentDate == null) return "";

        if (pattern == null || "".equals(pattern)) pattern = "yyyy年MM月dd日 E HH:mm ";

        return new SimpleDateFormat(pattern).format(sentDate);
    }

    /**
     * 获得邮件接收时间
     *
     * @param msg 邮件内容
     * @return yyyy年mm月dd日 星期X HH:mm
     * @throws MessagingException
     */
    public static String getReceiveDate(MimeMessage msg, String pattern) throws MessagingException {
        Date receivedDate = msg.getReceivedDate();
        if (receivedDate == null) return "";

        if (pattern == null || "".equals(pattern)) pattern = "yyyy年MM月dd日 E HH:mm ";

        return new SimpleDateFormat(pattern).format(receivedDate);
    }

    /**
     * 判断邮件中是否包含附件
     *
     * @param part 邮件内容
     * @return 邮件中存在附件返回true，不存在返回false
     * @throws MessagingException
     * @throws IOException
     */
    public static boolean isContainAttachment(Part part) throws MessagingException, IOException {
        boolean flag = false;
        if (part.isMimeType("multipart/*")) {
            MimeMultipart multipart = (MimeMultipart) part.getContent();
            int partCount = multipart.getCount();
            for (int i = 0; i < partCount; i++) {
                BodyPart bodyPart = multipart.getBodyPart(i);
                String disp = bodyPart.getDisposition();
                if (disp != null && (disp.equalsIgnoreCase(Part.ATTACHMENT) || disp.equalsIgnoreCase(Part.INLINE))) {
                    flag = true;
                } else if (bodyPart.isMimeType("multipart/*")) {
                    flag = isContainAttachment(bodyPart);
                } else {
                    String contentType = bodyPart.getContentType();
                    if (contentType.indexOf("application") != -1) {
                        flag = true;
                    }

                    if (contentType.indexOf("name") != -1) {
                        flag = true;
                    }
                }

                if (flag) break;
            }
        } else if (part.isMimeType("message/rfc822")) {
            flag = isContainAttachment((Part) part.getContent());
        }
        return flag;
    }

    /**
     * 判断邮件是否已读
     *
     * @param msg 邮件内容
     * @return 如果邮件已读返回true, 否则返回false
     * @throws MessagingException
     */
    public static boolean isSeen(MimeMessage msg) throws MessagingException {
        return msg.getFlags().contains(Flags.Flag.SEEN);
    }

    /**
     * 判断邮件是否需要阅读回执
     *
     * @param msg 邮件内容
     * @return 需要回执返回true, 否则返回false
     * @throws MessagingException
     */
    public static boolean isReplySign(MimeMessage msg) throws MessagingException {
        boolean replySign = false;
        String[] headers = msg.getHeader("Disposition-Notification-To");
        if (headers != null) replySign = true;
        return replySign;
    }

    /**
     * 获得邮件的优先级
     *
     * @param msg 邮件内容
     * @return 1(High):紧急  3:普通(Normal)  5:低(Low)
     * @throws MessagingException
     */
    public static String getPriority(MimeMessage msg) throws MessagingException {
        String priority = "普通";
        String[] headers = msg.getHeader("X-Priority");
        if (headers != null) {
            String headerPriority = headers[0];
            if (headerPriority.indexOf("1") != -1 || headerPriority.indexOf("High") != -1) priority = "紧急";
            else if (headerPriority.indexOf("5") != -1 || headerPriority.indexOf("Low") != -1) priority = "低";
            else priority = "普通";
        }
        return priority;
    }

    /**
     * 获得邮件文本内容
     *
     * @param part    邮件体
     * @param content 存储邮件文本内容的字符串
     * @throws MessagingException
     * @throws IOException
     */
    public static void getMailTextContent(Part part, StringBuffer content) throws MessagingException, IOException {
        //如果是文本类型的附件，通过getContent方法可以取到文本内容，但这不是我们需要的结果，所以在这里要做判断
        boolean isContainTextAttach = part.getContentType().indexOf("name") > 0;
        if (part.isMimeType("text/*") && !isContainTextAttach) {
            content.append(part.getContent().toString());
        } else if (part.isMimeType("message/rfc822")) {
            getMailTextContent((Part) part.getContent(), content);
        } else if (part.isMimeType("multipart/*")) {
            Multipart multipart = (Multipart) part.getContent();
            int partCount = multipart.getCount();
            for (int i = 0; i < partCount; i++) {
                BodyPart bodyPart = multipart.getBodyPart(i);
                getMailTextContent(bodyPart, content);
            }
        }
    }

    /**
     * 保存附件
     *
     * @param part    邮件中多个组合体中的其中一个组合体
     * @param destDir 附件保存目录
     * @throws UnsupportedEncodingException
     * @throws MessagingException
     * @throws FileNotFoundException
     * @throws IOException
     */
    public static void saveAttachment(Part part, String destDir) throws UnsupportedEncodingException, MessagingException, FileNotFoundException, IOException {
        if (part.isMimeType("multipart/*")) {
            Multipart multipart = (Multipart) part.getContent();    //复杂体邮件
            //复杂体邮件包含多个邮件体
            int partCount = multipart.getCount();
            for (int i = 0; i < partCount; i++) {
                //获得复杂体邮件中其中一个邮件体
                BodyPart bodyPart = multipart.getBodyPart(i);
                //某一个邮件体也有可能是由多个邮件体组成的复杂体
                String disp = bodyPart.getDisposition();
                if (disp != null && (disp.equalsIgnoreCase(Part.ATTACHMENT) || disp.equalsIgnoreCase(Part.INLINE))) {
                    InputStream is = bodyPart.getInputStream();
                    String s = decodeText(bodyPart.getFileName());
                    saveFile(bodyPart, is, destDir, s);
                } else if (bodyPart.isMimeType("multipart/*")) {
                    saveAttachment(bodyPart, destDir);
                } else {
                    String contentType = bodyPart.getContentType();
                    if (contentType.indexOf("name") != -1 || contentType.indexOf("application") != -1) {
                        String s = decodeText(bodyPart.getFileName());
                        saveFile(bodyPart, bodyPart.getInputStream(), destDir, s);
                    }
                }
            }
        } else if (part.isMimeType("message/rfc822")) {
            saveAttachment((Part) part.getContent(), destDir);
        }
    }

    /**
     * 读取输入流中的数据保存至指定目录
     *
     * @param is       输入流
     * @param fileName 文件名
     * @param destDir  文件存储目录
     * @throws FileNotFoundException
     * @throws IOException
     */
    private static void saveFile(BodyPart bodyPart, InputStream is, String destDir, String fileName) throws FileNotFoundException, IOException {
        BufferedInputStream bis = new BufferedInputStream(is);
        BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(new File(destDir + fileName)));
        int len = -1;
        while ((len = bis.read()) != -1) {
            bos.write(len);
            bos.flush();
        }
        bos.close();
        bis.close();
    }

    /**
     * 文本解码
     *
     * @param encodeText 解码MimeUtility.encodeText(String text)方法编码后的文本
     * @return 解码后的文本
     * @throws UnsupportedEncodingException
     */
    public static String decodeText(String encodeText) throws UnsupportedEncodingException {
        if (encodeText == null || "".equals(encodeText)) {
            return "";
        } else {
            return MimeUtility.decodeText(encodeText);
        }
    }
}