springboot发邮件，javaxmail收邮件功能

import com.sun.mail.imap.IMAPFolder;
import com.sun.mail.imap.protocol.IMAPProtocol;
import org.apache.tomcat.util.http.fileupload.IOUtils;
import org.springframework.util.ObjectUtils;

import javax.mail.*;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeUtility;
import java.io.*;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.*;

public class ReceivedIMAPMail {

    public static String NORM_DATETIME_PATTERN = "yyyy-MM-dd hh:mm:ss";
    
    private MimeMessage mimeMessage;
    /**
     * 附件下载后的存放目录
     */
    private String saveAttachPath = "";
    /**
     * 存放邮件内容的StringBuffer对象
     */
    private StringBuffer bodyText = new StringBuffer();

    /**
     * 构造函数,初始化一个MimeMessage对象
     *
     * @param mimeMessage
     */
    public ReceivedIMAPMail(MimeMessage mimeMessage) {
        this.mimeMessage = mimeMessage;
    }

    /**
     * 获得发件人的地址和姓名
     *
     * @return
     * @throws MessagingException
     */
    public String getFrom() throws MessagingException {
        InternetAddress address[] = (InternetAddress[]) mimeMessage.getFrom();
        String from = address[0].getAddress();
        if (from == null) {
            from = "";
        }
        String personal = address[0].getPersonal();

        if (personal == null) {
            personal = "";
        }

        String fromAddr = null;
        if (personal != null || from != null) {
            fromAddr = personal + "<" + from + ">";
        }
        return fromAddr;
    }

    /**
     * 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
     *
     * @param type "to"----收件人 "cc"---抄送人地址 "bcc"---密送人地址
     * @return
     * @throws MessagingException
     * @throws UnsupportedEncodingException
     */
    public String getMailAddress(String type) throws MessagingException, UnsupportedEncodingException {
        if (ObjectUtils.isEmpty(type)) {
            return "";
        }

        String addType = type.toUpperCase();

        if (!addType.equals("TO") && !addType.equals("CC") && !addType.equals("BCC")) {
            return "";
        }
        InternetAddress[] address;

        if (addType.equals("TO")) {
            address = (InternetAddress[]) mimeMessage.getRecipients(Message.RecipientType.TO);
        } else if (addType.equals("CC")) {
            address = (InternetAddress[]) mimeMessage.getRecipients(Message.RecipientType.CC);
        } else {
            address = (InternetAddress[]) mimeMessage.getRecipients(Message.RecipientType.BCC);
        }

        if (ObjectUtils.isEmpty(address)) {
            return "";
        }
        StringBuilder mailAddr = new StringBuilder();
        String emailAddr;
        String personal;
        for (int i = 0; i < address.length; i++) {
            emailAddr = address[i].getAddress();
            if (emailAddr == null) {
                emailAddr = "";
            } else {
                emailAddr = MimeUtility.decodeText(emailAddr);
            }
            personal = address[i].getPersonal();
            if (personal == null) {
                personal = "";
            } else {
                personal = MimeUtility.decodeText(personal);
            }
            mailAddr.append(",").append(personal).append("<").append(emailAddr).append(">");
        }
        return mailAddr.toString().substring(1);
    }

    /**
     * 获得邮件主题
     *
     * @return
     * @throws MessagingException
     * @throws UnsupportedEncodingException
     */
    public String getSubject() throws MessagingException, UnsupportedEncodingException {
        String subject = MimeUtility.decodeText(mimeMessage.getSubject());
        if (subject == null) {
            subject = "";
        }
        return subject;
    }

    /**
     * 获得邮件发送日期
     *
     * @return
     * @throws MessagingException
     */
    public String getSentDate() throws MessagingException {
        Date sentDate = mimeMessage.getSentDate();
        SimpleDateFormat format = new SimpleDateFormat(NORM_DATETIME_PATTERN);
        return format.format(sentDate);
    }

    /**
     * 获得邮件正文内容
     *
     * @return
     */
    public String getBodyText() {
        return bodyText.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
     * 
     * @param part
     * @throws MessagingException
     * @throws IOException
     */
    public void getMailContent(Part part) throws MessagingException, IOException {

        String contentType = part.getContentType();

        int nameIndex = contentType.indexOf("name");

        boolean conName = false;

        if (nameIndex != -1) {
            conName = true;
        }

        if (part.isMimeType("text/plain") && conName == false) {
            bodyText.append((String) part.getContent());
        } else if (part.isMimeType("text/html") && conName == false) {
            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++) {
                this.getMailContent(multipart.getBodyPart(i));
            }
        } else if (part.isMimeType("message/rfc822")) {
            this.getMailContent((Part) part.getContent());
        }
    }

    /**
     * 判断此邮件是否需要回执，如果需要回执返回"true",否则返回"false"
     *
     * @return
     * @throws MessagingException
     */
    public boolean getReplySign() throws MessagingException {

        boolean replySign = false;

        String needReply[] = mimeMessage.getHeader("Disposition-Notification-To");

        if (needReply != null) {
            replySign = true;
        }
        return replySign;
    }

    /**
     * 判断此邮件是否已读，如果未读返回false,反之返回true
     *
     * @return
     * @throws MessagingException
     */
    public boolean isNew() throws MessagingException {
        boolean isNew = false;
        Flags flags = mimeMessage.getFlags();
        Flags.Flag[] flag = flags.getSystemFlags();
        for (int i = 0; i < flag.length; i++) {
            if (flag[i] == Flags.Flag.SEEN) {
                isNew = true;
            }
        }
        return isNew;
    }

    /**
     * 判断此邮件是否包含附件
     *
     * @param part
     * @return
     * @throws MessagingException
     * @throws IOException
     */
    public boolean isContainAttach(Part part) throws MessagingException, IOException {
        boolean attachFlag = false;
        if (part.isMimeType("multipart/*")) {
            Multipart mp = (Multipart) part.getContent();
            BodyPart mPart;
            String conType;
            for (int i = 0; i < mp.getCount(); i++) {
                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 = this.isContainAttach(mPart);
                } else {
                    conType = mPart.getContentType();
                    if (conType.toLowerCase().indexOf("application") != -1
                            || conType.toLowerCase().indexOf("name") != -1) {
                        attachFlag = true;
                    }
                }
            }
        } else if (part.isMimeType("message/rfc822")) {
            attachFlag = isContainAttach((Part) part.getContent());
        }
        return attachFlag;
    }

    /**
     * 保存附件
     *
     * @param part
     * @throws MessagingException
     * @throws IOException
     */
    public void saveAttachMent(Part part) throws MessagingException, IOException {
        String fileName;
        if (part.isMimeType("multipart/*")) {
            Multipart mp = (Multipart) part.getContent();
            BodyPart mPart;
            for (int i = 0; i < mp.getCount(); i++) {
                mPart = mp.getBodyPart(i);
                String disposition = mPart.getDisposition();
                if (Part.ATTACHMENT.equals(disposition) || Part.INLINE.equals(disposition)) {
                    fileName = mPart.getFileName();
                    if (null != fileName && fileName.toLowerCase().indexOf("gb2312") != -1) {
                        fileName = MimeUtility.decodeText(fileName);
                    }
                    fileName = fileName.replaceAll("\?|=", "");
                    this.saveFile(fileName, mPart.getInputStream());
                } else if (mPart.isMimeType("multipart/*")) {
                    this.saveAttachMent(mPart);
                } else {
                    fileName = mPart.getFileName();
                    if ((fileName != null) && (fileName.toLowerCase().indexOf("GB2312") != -1)) {
                        fileName = MimeUtility.decodeText(fileName);
                        this.saveFile(fileName, mPart.getInputStream());
                    }
                }
            }
        } else if (part.isMimeType("message/rfc822")) {
            this.saveAttachMent((Part) part.getContent());
        }
    }

    /**
     * 设置附件存放路径
     *
     * @param attachPath
     */
    public void setAttachPath(String attachPath) {
        this.saveAttachPath = attachPath;
    }

    /**
     * 获得附件存放路径
     *
     * @return
     */
    public String getAttachPath() {
        return saveAttachPath;
    }

    /**
     * 真正的保存附件到指定目录里
     *
     * @param fileName
     * @param in
     * @throws IOException
     */
    private void saveFile(String fileName, InputStream in) throws IOException {
        String osName = System.getProperty("os.name");
        String storeDir = this.getAttachPath();
        if (null == osName) {
            osName = "";
        }
        if (osName.toLowerCase().indexOf("win") != -1) {
            if (ObjectUtils.isEmpty(storeDir))
                storeDir = "C:\tmp";
        } else {
            storeDir = "/tmp";
        }
        FileOutputStream fos = new FileOutputStream(new File(storeDir + File.separator + fileName));
        IOUtils.copy(in, fos);
        IOUtils.closeQuietly(fos);
        IOUtils.closeQuietly(in);
    }

    /**
     * 获取阿里云邮箱信息
     *
     * @param host     邮件服务器
     * @param username 邮箱名
     * @param password 密码
     * @param protocol 协议
     * @return
     * @throws MessagingException
     */
    public static Message[] getALiYunMessage(String host, String username, String password, String protocol)
            throws MessagingException {
        Properties props = new Properties();
        Session session = Session.getDefaultInstance(props, null);

        Store store = session.getStore(protocol);
        store.connect(host, username, password);

        Folder folder = store.getFolder("INBOX");
        folder.open(Folder.READ_ONLY);
        return folder.getMessages();
    }

    /**
     * 获取163邮箱信息
     *
     * @param host
     * @param username
     * @param password
     * @param protocol
     * @return
     * @throws MessagingException
     */
    public static Message[] getWEMessage(String host, String username, String password, String protocol)
            throws MessagingException {
        Properties props = System.getProperties();
        props.setProperty("mail.store.protocol", protocol);
        Session session = Session.getDefaultInstance(props, null);
        Store store = session.getStore(protocol);
        store.connect(host, username, password);
        Folder folder = store.getFolder("INBOX");

        if (folder instanceof IMAPFolder) {
            IMAPFolder imapFolder = (IMAPFolder) folder;
            // javamail中使用id命令有校验checkOpened, 所以要去掉id方法中的checkOpened();
            imapFolder.doCommand(new IMAPFolder.ProtocolCommand() {
                public Object doCommand(IMAPProtocol p) throws com.sun.mail.iap.ProtocolException {
                    Map<String, String> gmap = new HashMap<>();
                    gmap.put("GUID", "FUTONG");
                    // p.id("FUTONG");
                    p.id(gmap);
                    return null;
                }
            });
        }

        if (folder != null) {
            folder.open(Folder.READ_WRITE);
        }

        return folder.getMessages();
    }

    /**
     * 过滤邮箱信息
     *
     * @param messages
     * @param fromMail  只读取该邮箱发来的邮件，如果为空则不过滤
     * @param startDate 只读取该日期以后的邮件，如果为空则不过滤
     * @return
     * @throws MessagingException
     */
    public static List<Message> filterMessage(Message[] messages, String fromMail, String startDate)
            throws MessagingException, ParseException {
        List<Message> messageList = new ArrayList<>();
        if (ObjectUtils.isEmpty(messages)) {
            return messageList;
        }
        boolean isEnptyFromMail = ObjectUtils.isEmpty(fromMail);
        boolean isEnptyStartDate = ObjectUtils.isEmpty(startDate);
        if (isEnptyFromMail && isEnptyStartDate) {
            return Arrays.asList(messages);
        }

        String from;
        for (Message message : messages) {
            from = (message.getFrom()[0]).toString();
            if (isEnptyFromMail) {
                if (new SimpleDateFormat(NORM_DATETIME_PATTERN).parse(startDate).getTime() > message.getSentDate()
                        .getTime()) {
                    continue;
                }
            } else if (null != from && from.contains(fromMail)) {
                if (!isEnptyStartDate && new SimpleDateFormat(NORM_DATETIME_PATTERN).parse(startDate)
                        .getTime() > message.getSentDate().getTime()) {
                    continue;
                }
            } else {
                continue;
            }
            messageList.add(message);
        }
        return messageList;
    }

    /**
     * 打印邮件
     *
     * @param messageList
     * @throws IOException
     * @throws MessagingException
     */
    public static void printMailMessage(List<Message> messageList) throws IOException, MessagingException {
        System.out.println("邮件数量:" + messageList.size());
        ReceivedIMAPMail re;
        Message message;
        for (int i = 0, leng = messageList.size(); i < leng; i++) {
            message = messageList.get(i);
            re = new ReceivedIMAPMail((MimeMessage) message);
            System.out.println("邮件【" + i + "】主题:" + re.getSubject());
            System.out.println("邮件【" + i + "】发送时间:" + re.getSentDate());
            System.out.println("邮件【" + i + "】是否需要回复:" + re.getReplySign());
            System.out.println("邮件【" + i + "】是否已读:" + re.isNew());
            System.out.println("邮件【" + i + "】是否包含附件:" + re.isContainAttach(message));
            System.out.println("邮件【" + i + "】发送人地址:" + re.getFrom());
            System.out.println("邮件【" + i + "】收信人地址:" + re.getMailAddress("to"));
            System.out.println("邮件【" + i + "】抄送:" + re.getMailAddress("cc"));
            System.out.println("邮件【" + i + "】暗抄:" + re.getMailAddress("bcc"));
            System.out.println("邮件【" + i + "】发送时间:" + re.getSentDate());
            System.out.println("邮件【" + i + "】邮件ID:" + ((MimeMessage) message).getMessageID());
            re.getMailContent(message);
            // System.out.println("邮件【" + i + "】正文内容:
" + re.getBodyText());
            if(re.isContainAttach(message)) {
                System.out.println("邮件包含附件，开始下载到D:\xl下面");
                re.setAttachPath("D:\xl\mail\");
                re.saveAttachMent(message);
            }
        }
    }

    public static void main(String[] args) throws MessagingException, IOException, ParseException {
        // 阿里云登录信息
//        String host = "pop3.mxhichina.com";
//        String username = "liwei@xiaostudy.com";
//        String password = "密码";
//        String protocol = "pop3";
//        String fromMail = "XXX@163.com";
//        String startDate = "2020-2-24 23:35:40";
//        List<Message> messageList = filterMessage(getALiYunMessage(host, username, password, protocol), fromMail, startDate);

        // 163登录信息
        String host = "imap.163.com";
        String username = "*****@163.com";
        String password = "客户端授权码";
        String protocol = "imaps";
        String fromMail = "";// "****@163.com";
        String startDate = "";// "2020-2-24 23:35:40";
        List<Message> messageList = filterMessage(getWEMessage(host, username, password, protocol), fromMail,
                startDate);

        printMailMessage(messageList);
    }
}

解决可能的附件文件乱码问题：

/**
     * 保存附件
     *
     * @param part
     * @throws MessagingException
     * @throws IOException
     */
    public void saveAttachMent(Part part) throws MessagingException, IOException {
        String fileName;
        if (part.isMimeType("multipart/*")) {
            Multipart mp = (Multipart) part.getContent();
            BodyPart mPart;
            for (int i = 0; i < mp.getCount(); i++) {
                mPart = mp.getBodyPart(i);
                String disposition = mPart.getDisposition();
                if (Part.ATTACHMENT.equals(disposition) || Part.INLINE.equals(disposition)) {
                    fileName = mPart.getFileName();
                    if (null != fileName && fileName.toLowerCase().indexOf("gb2312") != -1) {
                        fileName = MimeUtility.decodeText(fileName);
                    }
                    if(null != fileName && fileName.toLowerCase().indexOf("utf-8") != -1) {
                        fileName = MimeUtility.decodeWord(fileName);
                    }
                    //fileName = fileName.replaceAll("\?|=", "");
                    this.saveFile(fileName, mPart.getInputStream());
                } else if (mPart.isMimeType("multipart/*")) {
                    this.saveAttachMent(mPart);
                } else {
                    fileName = mPart.getFileName();
                    if ((fileName != null) && (fileName.toLowerCase().indexOf("gb2312") != -1)) {
                        fileName = MimeUtility.decodeText(fileName);
                        this.saveFile(fileName, mPart.getInputStream());
                    }
                    if ((fileName != null) && (fileName.toLowerCase().indexOf("utf-8") != -1)) {
                        fileName = MimeUtility.decodeWord(fileName);
                        this.saveFile(fileName, mPart.getInputStream());
                    }
                    
                }
            }
        } else if (part.isMimeType("message/rfc822")) {
            this.saveAttachMent((Part) part.getContent());
        }
    }

发邮件代码：

compile "org.springframework.boot:spring-boot-starter-mail:1.5.8"

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.FileSystemResource;
import org.springframework.mail.SimpleMailMessage;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.mail.javamail.JavaMailSenderImpl;
import org.springframework.mail.javamail.MimeMessageHelper;
import org.springframework.stereotype.Component;

import javax.mail.MessagingException;
import javax.mail.internet.MimeMessage;
import java.io.File;
import java.util.Date;

@Component
public class SpringbootMailService {

    @Autowired
    JavaMailSender javaMailSender;

    public String sendSimpleMail(String to, String cc, String title, String content) {
        // 1.构建一个邮件对象
        SimpleMailMessage message = new SimpleMailMessage();
        // 2.设置邮件主题
        message.setSubject(title);
        // 3.设置邮件发送者
        message.setFrom("****@163.com");
        // 4. 设置邮件接收者，可以有多个接收者
        message.setTo(to);
        // 5.设置邮件抄送人，可以有多个抄送人
        message.setCc(cc);
        // 6.设置隐秘抄送人，可以有多个
        // message.setBcc();
        // 7.设置邮件发送日期
        message.setSentDate(new Date());
        // 8. 设置邮件的正文
        message.setText(content);
        try {
            // 9. 发送邮件
            javaMailSender.send(message);
            return "success";
        } catch (Throwable e) {
            return e.getMessage();
        }
    }

    public void sendSimpleMail() {
        // 1.构建一个邮件对象
        SimpleMailMessage message = new SimpleMailMessage();
        // 2.设置邮件主题
        message.setSubject("这是一封测试邮件");
        // 3.设置邮件发送者
        message.setFrom("****@163.com");
        // 4. 设置邮件接收者，可以有多个接收者
        message.setTo("*****");
        // 5.设置邮件抄送人，可以有多个抄送人
        // message.setCc();
        // 6.设置隐秘抄送人，可以有多个
        // message.setBcc();
        // 7.设置邮件发送日期
        message.setSentDate(new Date());
        // 8. 设置邮件的正文
        message.setText("这是测试邮件的正文");
        // 9. 发送邮件
        javaMailSender.send(message);
    }

    public void sendAttachFileMail() throws MessagingException {
        // 1. 构建邮件对象，注意，这里要通过 javaMailSender 来获取一个复杂邮件对象
        MimeMessage mimeMessage = javaMailSender.createMimeMessage();
        // 2. MimeMessageHelper 是一个邮件配置的辅助工具类，true 表示构建一个 multipart message 类型的邮件
        MimeMessageHelper helper = new MimeMessageHelper(mimeMessage, true);
        // 3. 针对工具类，配置邮件发送的基本信息
        helper.setSubject("图片");
        helper.setFrom("******@163.com");
        helper.setTo("l*****");
        helper.setCc("*****@163.com");
//        helper.setBcc();
        helper.setSentDate(new Date());
        helper.setText("这是测试邮件的正文");
        // 4. 添加邮件附件
        helper.addAttachment("杨幂.jpg", new File("C:\Users\Administrator\Pictures\0.jpg"));
        // 5. 发送邮件
        javaMailSender.send(mimeMessage);
    }

    public void sendImgResMail() throws MessagingException {
        MimeMessage mimeMessage = javaMailSender.createMimeMessage();
        MimeMessageHelper helper = new MimeMessageHelper(mimeMessage, true);
        helper.setSubject("这是一封测试邮件");
        helper.setFrom("*****@163.com");
        helper.setTo("*****@163.com");
        helper.setSentDate(new Date());
        helper.setText(
                "<p>hello 大家好，这是一封测试邮件，这封邮件包含两种图片，分别如下</p><p>第一张图片：</p><img src='cid:p01'/><p>第二张图片：</p><img src='cid:p02'/>",
                true);
        helper.addInline("p01", new FileSystemResource(new File("C:\Users\sang\Downloads\javaboy.png")));
        helper.addInline("p02", new FileSystemResource(new File("C:\Users\sang\Downloads\javaboy2.png")));
        javaMailSender.send(mimeMessage);
    }

    public static void main(String[] args) throws Throwable {
        SpringbootMailService service = new SpringbootMailService();
        JavaMailSenderImpl javaMailSender = new JavaMailSenderImpl();
        javaMailSender.setDefaultEncoding("UTF-8");
        javaMailSender.setHost("smtp.163.com");
        javaMailSender.setPort(25);
        javaMailSender.setUsername("*****@163.com");
        javaMailSender.setPassword("授权码");
        service.javaMailSender = javaMailSender;
        service.sendAttachFileMail();
    }

}

收邮件几乎搞了一天，就差几行代码，最后网上搜到了。网上人才多啊！

/** * 保存附件 * * @param part * @throws MessagingException * @throws IOException */public void saveAttachMent(Part part) throws MessagingException, IOException {String fileName;if (part.isMimeType("multipart/*")) {Multipart mp = (Multipart) part.getContent();BodyPart mPart;for (int i = 0; i < mp.getCount(); i++) {mPart = mp.getBodyPart(i);String disposition = mPart.getDisposition();if (Part.ATTACHMENT.equals(disposition) || Part.INLINE.equals(disposition)) {fileName = mPart.getFileName();if (null != fileName && fileName.toLowerCase().indexOf("gb2312") != -1) {fileName = MimeUtility.decodeText(fileName);}if(null != fileName && fileName.toLowerCase().indexOf("utf-8") != -1) {fileName = MimeUtility.decodeWord(fileName);}//fileName = fileName.replaceAll("\?|=", "");this.saveFile(fileName, mPart.getInputStream());} else if (mPart.isMimeType("multipart/*")) {this.saveAttachMent(mPart);} else {fileName = mPart.getFileName();if ((fileName != null) && (fileName.toLowerCase().indexOf("gb2312") != -1)) {fileName = MimeUtility.decodeText(fileName);this.saveFile(fileName, mPart.getInputStream());}if ((fileName != null) && (fileName.toLowerCase().indexOf("utf-8") != -1)) {fileName = MimeUtility.decodeWord(fileName);this.saveFile(fileName, mPart.getInputStream());}}}} else if (part.isMimeType("message/rfc822")) {this.saveAttachMent((Part) part.getContent());}}