MailMessageInfo 邮件对象

import cn.hutool.core.io.FileUtil;
import cn.hutool.core.util.StrUtil;
import lombok.Data;

import javax.mail.*;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeUtility;
import java.io.File;
import java.io.InputStream;
import java.nio.file.Paths;
import java.util.Date;
import java.util.Objects;
import java.util.Optional;

@Data
public class MailMessageInfo {

    private MimeMessage mimeMessage;

    /**
     * 附件下载后的存放目录
     */
    private String saveAttachPath;

    /**
     * 主题
     */
    private String subject;

    /**
     * 获得邮件发送日期
     */
    private Date sendDate;

    /**
     * 发件人
     */
    private String fromPerson;

    /**
     * 收件人
     */
    private String toPerson;

    /**
     * 抄送人
     */
    private String ccPerson;

    /**
     * 密送人
     */
    private String bccPerson;

    /**
     * Message-ID
     */
    private String messageID;

    /**
     * 是否已读
     */
    private Boolean hasRead;

    /**
     * 是否需要回执
     */
    private Boolean needReplay;

    /**
     * 存放邮件内容
     */
    private final StringBuffer bodyText = new StringBuffer();

    public MailMessageInfo(MimeMessage mimeMessage) throws Exception {
        this.mimeMessage = mimeMessage;
        this.subject = Optional.ofNullable(MimeUtility.decodeText(mimeMessage.getSubject())).orElse("");
        this.sendDate = mimeMessage.getSentDate();
        this.fromPerson = getFrom();
        this.toPerson = getMailAddress("to");
        this.ccPerson = getMailAddress("cc");
        this.bccPerson = getMailAddress("bcc");
        this.needReplay = mimeMessage.getHeader("Disposition-Notification-To") != null;
        this.messageID = mimeMessage.getMessageID();
        this.hasRead = checkHasRead();
        parseMailContent(mimeMessage);
    }

    /**
     * 获得发件人的地址和姓名
     */
    private String getFrom() throws Exception {
        InternetAddress[] address = (InternetAddress[]) mimeMessage.getFrom();
        String from = Optional.ofNullable(address[0].getAddress()).orElse("");
        String personal = Optional.ofNullable(address[0].getPersonal()).orElse("");
        return personal + "<" + from + ">";
    }

    /**
     * 获得邮件的收件人，抄送，和密送的地址和姓名，根据所传递的参数的不同 "to"----收件人 "cc"---抄送人地址 "bcc"---密送人地址
     */
    private String getMailAddress(String type) throws Exception {
        String addtype = type.toUpperCase();
        InternetAddress[] address = null;
        if (Objects.equals(addtype, "TO")) {
            address = (InternetAddress[]) mimeMessage.getRecipients(Message.RecipientType.TO);
        } else if (Objects.equals(addtype, "CC")) {
            address = (InternetAddress[]) mimeMessage.getRecipients(Message.RecipientType.CC);
        } else if (Objects.equals(addtype, "BCC")) {
            address = (InternetAddress[]) mimeMessage.getRecipients(Message.RecipientType.BCC);
        }

        StringBuilder mailaddr = new StringBuilder();
        if (address != null) {
            for (InternetAddress internetAddress : address) {
                String email = MimeUtility.decodeText(Optional.ofNullable(internetAddress.getAddress()).orElse(""));
                String personal = MimeUtility.decodeText(Optional.ofNullable(internetAddress.getPersonal()).orElse(""));
                mailaddr.append(",").append(personal).append("<").append(email).append(">");
            }
            mailaddr = new StringBuilder(mailaddr.substring(1));
        }

        return mailaddr.toString();
    }

    /**
     * 解析邮件，把得到的邮件内容保存到一个StringBuffer对象中，解析邮件 主要是根据MimeType类型的不同执行不同的操作，一步一步的解析
     */
    public void parseMailContent(Part part) throws Exception {
        String contentType = part.getContentType();
        int nameIndex = contentType.indexOf("name");
        boolean hasNameKeyword = nameIndex != -1;
        if (!hasNameKeyword && (part.isMimeType("text/plain") || part.isMimeType("text/html"))) {
            bodyText.append((String) part.getContent());
        } else if (part.isMimeType("multipart/*")) {
            Multipart multipart = (Multipart) part.getContent();
            int counts = multipart.getCount();
            for (int i = 0; i < counts; i++) {
                parseMailContent(multipart.getBodyPart(i));
            }
        } else if (part.isMimeType("message/rfc822")) {
            parseMailContent((Part) part.getContent());
        }
    }

    /**
     * 判断此邮件是否已读，如果未读返回返回false,反之返回true
     */
    public boolean checkHasRead() throws MessagingException {
        Flags flags = mimeMessage.getFlags();
        Flags.Flag[] flag = flags.getSystemFlags();
        for (Flags.Flag value : flag) {
            if (value == Flags.Flag.SEEN) {
                return true;
            }
        }
        return false;
    }

    /**
     * 判断此邮件是否包含附件
     */
    public boolean isContainAttach(Part part) throws Exception {
        boolean attachflag = false;
        if (part.isMimeType("multipart/*")) {
            Multipart mp = (Multipart) part.getContent();
            for (int i = 0; i < mp.getCount(); i++) {
                BodyPart mpart = mp.getBodyPart(i);
                String disposition = mpart.getDisposition();
                if (Part.ATTACHMENT.equals(disposition) || Part.INLINE.equals(disposition)) {
                    attachflag = true;
                } else if (mpart.isMimeType("multipart/*")) {
                    attachflag = isContainAttach(mpart);
                } else {
                    String contentType = part.getContentType().toLowerCase();
                    attachflag = StrUtil.containsAny(contentType, "application", "name");
                }
            }
        } else if (part.isMimeType("message/rfc822")) {
            attachflag = isContainAttach((Part) part.getContent());
        }
        return attachflag;
    }

    /**
     * 保存附件
     */
    public File saveAttachment(Part part) throws Exception {
        String fileName;
        if (part.isMimeType("multipart/*")) {
            Multipart mp = (Multipart) part.getContent();
            for (int i = 0; i < mp.getCount(); i++) {
                BodyPart bodyPart = mp.getBodyPart(i);
                String disposition = bodyPart.getDisposition();
                if (Part.ATTACHMENT.equals(disposition) || Part.INLINE.equals(disposition)) {
                    fileName = MimeUtility.decodeText(bodyPart.getFileName()).replaceAll("/", "_");
                    return saveFile(fileName, bodyPart.getInputStream());
                } else if (bodyPart.isMimeType("multipart/*")) {
                    return saveAttachment(bodyPart);
                } else {
                    String bodyPartFileName = bodyPart.getFileName();
                    if (bodyPartFileName != null) {
                        bodyPartFileName = MimeUtility.decodeText(bodyPartFileName);
                        return saveFile(bodyPartFileName, bodyPart.getInputStream());
                    }
                }
            }
        } else if (part.isMimeType("message/rfc822")) {
            return saveAttachment((Part) part.getContent());
        }

        return null;
    }

    /**
     * 真正的保存附件到指定目录里
     */
    private File saveFile(String fileName, InputStream in) {
        if (StrUtil.isBlankIfStr(fileName)) {
            return null;
        }
        String storedir = getSaveAttachPath();
        if (!FileUtil.exist(storedir)) {
            storedir = System.getProperty("java.io.tmpdir");
        }
        File storefile = Paths.get(storedir, fileName).toFile();
        try {
            FileUtil.writeFromStream(in, storefile);
            return storefile;
        } catch (Exception e) {
            throw new RuntimeException("文件保存失败!", e);
        }
    }

}