Java-接收郵件

spring & jakarta-common-mail 已提供很好的封裝在發送 mail 這方面, 但並未找到有提供接收 mail 的部份.
以下提供範例, 僅供參考

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;
import java.util.Properties;
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.MimeMultipart;

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.io.IOUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class MailReceiver {
    private static final Log log = LogFactory.getLog(MailReceiver.class);

    private String host = null;
    private String username = null;
    private String password = null;
    private String attachPath = null;

    // receive
    public void reveiveMail() throws Exception {

        Properties props = new Properties();
        Session session = Session.getDefaultInstance(props, null);
        Store store = session.getStore("pop3");
        store.connect(getHost(), getUsername(), getPassword());

        // default 是 inbox
        Folder folder = store.getFolder("INBOX");

        // can delete, 設定對信箱的操作
        folder.open(Folder.READ_WRITE);

        // 讀取信件
        Message message[] = folder.getMessages();

        // 有幾封信
        int messageLength = message.length;

        log.info("Messages's length: " + messageLength);

        for (int i = 0; i < message.length; i++) {
            // 設定對信的操作, 接收完要不要刪除
            message[i].setFlag(Flags.Flag.DELETED, false);

            handleMultipart(message[i]);
        }

        // close
        if (folder != null) {
            folder.close(true);
        }
        if (store != null) {
            store.close();
        }
    }

    // handle
    private void handleMultipart(Message msg) throws Exception {
        handle(msg);
        String disposition;
        Multipart mp = (Multipart) msg.getContent();
        int mpCount = mp.getCount();
        for (int m = 0; m < mpCount; m++) {

            BodyPart part = mp.getBodyPart(m);
            disposition = part.getDisposition();

            // 處理附件
            if (disposition != null && disposition.equals(Part.ATTACHMENT)) {
                saveAttach(part, getAttachPath());
            } else {
                // 其它的物件
                Object obj = part.getContent();
                if (obj instanceof MimeMultipart) {
                    MimeMultipart mm = (MimeMultipart) obj;
                    showContent(mm);
                }
            }
        }
    }

    private void showContent(MimeMultipart mm) {
        try {
            log.info("content-type : " + mm.getContentType());
            int count = mm.getCount();
            log.info("count        : " + count);
            for (int i = 0; i < count; i++) {
                log.info(i + "----");
                log.info(mm.getBodyPart(i).getContent());
            }
        } catch (MessagingException e) {
            log.error(e.getMessage(), e);
        } catch (IOException e) {
            log.error(e.getMessage(), e);
        }
    }

    private static void handle(Message msg) throws Exception {
        log.info("郵件主題 : " + msg.getSubject());
        log.info("郵件作者 : " + Arrays.toString(msg.getFrom()));
        log.info("發送日期 : " + msg.getSentDate());
    }

    private static void saveAttach(BodyPart part, String filePath)
            throws Exception {

        String temp = part.getFileName();
        log.info("temp file name : " + temp);
        
        String fileName = temp;
        if (temp.length() > 8 && temp.indexOf("?=") != -1) {
            String s = temp.substring(8, temp.indexOf("?="));
            fileName = new String(new Base64().decode(s.getBytes("big5")), "big5");
        }
        
        log.info(" get attachment : " + fileName);
        InputStream in = part.getInputStream();

        // save
        log.info(filePath + "" + fileName);
        FileOutputStream out = new FileOutputStream(new File(filePath + fileName));
        IOUtils.copy(in, out);
    }

    public String getAttachPath() {
        return attachPath;
    }

    public void setAttachPath(String attachPath) {
        this.attachPath = attachPath;
    }

    public String getHost() {
        return host;
    }

    public void setHost(String host) {
        this.host = host;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public static void main(String[] args) {

        MailReceiver receiver = new MailReceiver();
        receiver.setHost("staff.pchome.com.tw");
        receiver.setUsername("1234");
        receiver.setPassword("1234");
        receiver.setAttachPath("D:\\email\\");
        new File(receiver.getAttachPath()).mkdirs();
        try {
            receiver.reveiveMail();
        } catch (Exception e) {
            log.error(e.getMessage(), e);
        }
    }
}