JavaMail--使用POP3接收邮件

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引用

关键技术：
javax.mail.Store：该类实现特定邮件协议（如POP3）上的读、写、监视、查找等操作。通过它的getFolder方法打开一个javax.mail.Folder。
javax.mail.Folder：该类用于描述邮件的分级组织，如收件箱、草稿箱。它的open方法打开分级组织，close方法关闭分级组织，getMessages方法获得分级组织中的邮件，getNewMessageCount方法获得分级组织中新邮件的数量，getUnreadMessageCount方法获得分级组织中未读邮件的数量
根据MimeMessage的getFrom和getRecipients方法获得邮件的发件人和收件人地址列表，得到的是InternetAddress数组，根据InternetAddress的getAddress方法获得邮件地址，根据InternetAddress的getPersonal方法获得邮件地址的个人信息。
MimeMessage的getSubject、getSentDate、getMessageID方法获得邮件的主题、发送日期和邮件的ID（表示邮件）。
通过MimeMessage的getContent方法获得邮件的内容，如果邮件是MIME邮件，那么得到的是一个Multipart的对象，如果是一共普通的文本邮件，那么得到的是BodyPart对象。Multipart可以包含多个BodyPart，而BodyPart本身又可以是Multipart。BodyPart的MimeType类型为“multipart/*”时，表示它是一个Mutipart。
但一个BodyPart的disposition属性等于Part.ATTACHMENT或者Part.INLINE常量时，表示它带有附件。通过BodyPart的getInputStream方法可以获得附件的输入流。

package book.email;

import java.io.File;
import java.util.Properties;
/**
 * 收邮件的基本信息
 */
public class MailReceiverInfo {
    // 邮件服务器的IP、端口和协议
    private String mailServerHost;
    private String mailServerPort = "110";
    private String protocal = "pop3";
    // 登陆邮件服务器的用户名和密码
    private String userName;
    private String password;
    // 保存邮件的路径
    private String attachmentDir = "C:/temp/";
    private String emailDir = "C:/temp/";
    private String emailFileSuffix = ".eml";
    // 是否需要身份验证
    private boolean validate = true;

    /**
     * 获得邮件会话属性
     */
    public Properties getProperties(){
        Properties p = new Properties();
        p.put("mail.pop3.host", this.mailServerHost);
        p.put("mail.pop3.port", this.mailServerPort);
        p.put("mail.pop3.auth", validate ? "true" : "false");
        return p;
    }
    
    public String getProtocal() {
        return protocal;
    }

    public void setProtocal(String protocal) {
        this.protocal = protocal;
    }

    public String getAttachmentDir() {
        return attachmentDir;
    }

    public void setAttachmentDir(String attachmentDir) {
        if (!attachmentDir.endsWith(File.separator)){
            attachmentDir = attachmentDir + File.separator;
        }
        this.attachmentDir = attachmentDir;
    }

    public String getEmailDir() {
        return emailDir;
    }

    public void setEmailDir(String emailDir) {
        if (!emailDir.endsWith(File.separator)){
            emailDir = emailDir + File.separator;
        }
        this.emailDir = emailDir;
    }

    public String getEmailFileSuffix() {
        return emailFileSuffix;
    }

    public void setEmailFileSuffix(String emailFileSuffix) {
        if (!emailFileSuffix.startsWith(".")){
            emailFileSuffix = "." + emailFileSuffix;
        }
        this.emailFileSuffix = emailFileSuffix;
    }

    public String getMailServerHost() {
        return mailServerHost;
    }

    public void setMailServerHost(String mailServerHost) {
        this.mailServerHost = mailServerHost;
    }

    public String getMailServerPort() {
        return mailServerPort;
    }

    public void setMailServerPort(String mailServerPort) {
        this.mailServerPort = mailServerPort;
    }

    public String getPassword() {
        return password;
    }

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

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public boolean isValidate() {
        return validate;
    }

    public void setValidate(boolean validate) {
        this.validate = validate;
    }
    
}







package book.email;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringReader;
import java.io.UnsupportedEncodingException;
import java.util.Date;

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.NoSuchProviderException;
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.MimeUtility;

/**
 * 邮件接收器，目前支持pop3协议。
 * 能够接收文本、HTML和带有附件的邮件
 */
public class MailReceiver {
    // 收邮件的参数配置
    private MailReceiverInfo receiverInfo;
    // 与邮件服务器连接后得到的邮箱
    private Store store;
    // 收件箱
    private Folder folder;
    // 收件箱中的邮件消息
    private Message[] messages;
    // 当前正在处理的邮件消息
    private Message currentMessage;

    private String currentEmailFileName;

    public MailReceiver(MailReceiverInfo receiverInfo) {
        this.receiverInfo = receiverInfo;
    }
    /**
     * 收邮件
     */
    public void receiveAllMail() throws Exception{
        if (this.receiverInfo == null){
            throw new Exception("必须提供接收邮件的参数！");
        }
        // 连接到服务器
        if (this.connectToServer()) {
            // 打开收件箱
            if (this.openInBoxFolder()) {
                // 获取所有邮件
                this.getAllMail();
                this.closeConnection();
            } else {
                throw new Exception("打开收件箱失败！");
            }
        } else {
            throw new Exception("连接邮件服务器失败！");
        }
    }
    
    /**
     * 登陆邮件服务器
     */
    private boolean connectToServer() {
        // 判断是否需要身份认证
        MyAuthenticator authenticator = null;
        if (this.receiverInfo.isValidate()) {
            // 如果需要身份认证，则创建一个密码验证器
            authenticator = new MyAuthenticator(this.receiverInfo.getUserName(),
                    this.receiverInfo.getPassword());
        }
        //创建session
        Session session = Session.getInstance(this.receiverInfo
                .getProperties(), authenticator);

        //创建store,建立连接
        try {
            this.store = session.getStore(this.receiverInfo.getProtocal());
        } catch (NoSuchProviderException e) {
            System.out.println("连接服务器失败！");
            return false;
        }

        System.out.println("connecting");
        try {
            this.store.connect();
        } catch (MessagingException e) {
            System.out.println("连接服务器失败！");
            return false;
        }
        System.out.println("连接服务器成功");
        return true;
    }
    /**
     * 打开收件箱
     */
    private boolean openInBoxFolder() {
        try {
            this.folder = store.getFolder("INBOX");
            // 只读
            folder.open(Folder.READ_ONLY);
            return true;
        } catch (MessagingException e) {
            System.err.println("打开收件箱失败！");
        }
        return false;
    }
    /**
     * 断开与邮件服务器的连接
     */
    private boolean closeConnection() {
        try {
            if (this.folder.isOpen()) {
                this.folder.close(true);
            }
            this.store.close();
            System.out.println("成功关闭与邮件服务器的连接！");
            return true;
        } catch (Exception e) {
            System.out.println("关闭和邮件服务器之间连接时出错！");
        }
        return false;
    }
    
    /**
     * 获取messages中的所有邮件
     * @throws MessagingException 
     */
    private void getAllMail() throws MessagingException {
        //从邮件文件夹获取邮件信息
        this.messages = this.folder.getMessages();
        System.out.println("总的邮件数目：" + messages.length);
        System.out.println("新邮件数目：" + this.getNewMessageCount());
        System.out.println("未读邮件数目：" + this.getUnreadMessageCount());
        //将要下载的邮件的数量。
        int mailArrayLength = this.getMessageCount();
        System.out.println("一共有邮件" + mailArrayLength + "封");
        int errorCounter = 0; //邮件下载出错计数器
        int successCounter = 0;
        for (int index = 0; index < mailArrayLength; index++) {
            try {
                this.currentMessage = (messages[index]); //设置当前message
                System.out.println("正在获取第" + index + "封邮件");
                this.showMailBasicInfo();
                getMail(); //获取当前message
                System.out.println("成功获取第" + index + "封邮件");
                successCounter++;
            } catch (Throwable e) {
                errorCounter++;
                System.err.println("下载第" + index + "封邮件时出错");
            }
        }
        System.out.println("------------------");
        System.out.println("成功下载了" + successCounter + "封邮件");
        System.out.println("失败下载了" + errorCounter + "封邮件");
        System.out.println("------------------");
    }

    /**
     * 显示邮件的基本信息
     */
    private void showMailBasicInfo() throws Exception{
        showMailBasicInfo(this.currentMessage);
    }
    private void showMailBasicInfo(Message message) throws Exception {
        System.out.println("-------- 邮件ID：" + this.getMessageId()
                + " ---------");
        System.out.println("From：" + this.getFrom());
        System.out.println("To：" + this.getTOAddress());
        System.out.println("CC：" + this.getCCAddress());
        System.out.println("BCC：" + this.getBCCAddress());
        System.out.println("Subject：" + this.getSubject());
        System.out.println("发送时间：：" + this.getSentDate());
        System.out.println("是新邮件？" + this.isNew());
        System.out.println("要求回执？" + this.getReplySign());
        System.out.println("包含附件？" + this.isContainAttach());
        System.out.println("------------------------------");
    }

    /**
     * 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 getTOAddress() throws Exception {
        return getMailAddress("TO", this.currentMessage);
    }

    private String getCCAddress() throws Exception {
        return getMailAddress("CC", this.currentMessage);
    }

    private String getBCCAddress() throws Exception {
        return getMailAddress("BCC", this.currentMessage);
    }

    /**
     * 获得邮件地址
     * @param type        类型，如收件人、抄送人、密送人
     * @param mimeMessage    邮件消息
     * @return
     * @throws Exception
     */
    private String getMailAddress(String type, Message mimeMessage)
            throws Exception {
        String mailaddr = "";
        String addtype = type.toUpperCase();
        InternetAddress[] address = null;
        if (addtype.equals("TO") || addtype.equals("CC")
                || addtype.equals("BCC")) {
            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 (address != null) {
                for (int i = 0; i < address.length; i++) {
                    // 先获取邮件地址
                    String email = address[i].getAddress();
                    if (email == null){
                        email = "";
                    }else {
                        email = MimeUtility.decodeText(email);
                    }
                    // 再取得个人描述信息
                    String personal = address[i].getPersonal();
                    if (personal == null){
                        personal = "";
                    } else {
                        personal = MimeUtility.decodeText(personal);
                    }
                    // 将个人描述信息与邮件地址连起来
                    String compositeto = personal + "<" + email + ">";
                    // 多个地址时，用逗号分开
                    mailaddr += "," + compositeto;
                }
                mailaddr = mailaddr.substring(1);
            }
        } else {
            throw new Exception("错误的地址类型！!");
        }
        return mailaddr;
    }

    /**
     * 获得发件人的地址和姓名
     * @throws Exception
     */
    private String getFrom() throws Exception {
        return getFrom(this.currentMessage);
    }

    private String getFrom(Message mimeMessage) throws Exception {
        InternetAddress[] address = (InternetAddress[]) mimeMessage.getFrom();
        // 获得发件人的邮箱
        String from = address[0].getAddress();
        if (from == null){
            from = "";
        }
        // 获得发件人的描述信息
        String personal = address[0].getPersonal();
        if (personal == null){
            personal = "";
        }
        // 拼成发件人完整信息
        String fromaddr = personal + "<" + from + ">";
        return fromaddr;
    }

    /**
     * 获取messages中message的数量
     * @return
     */
    private int getMessageCount() {
        return this.messages.length;
    }

    /**
     * 获得收件箱中新邮件的数量
     * @return
     * @throws MessagingException
     */
    private int getNewMessageCount() throws MessagingException {
        return this.folder.getNewMessageCount();
    }

    /**
     * 获得收件箱中未读邮件的数量
     * @return
     * @throws MessagingException
     */
    private int getUnreadMessageCount() throws MessagingException {
        return this.folder.getUnreadMessageCount();
    }

    /**
     * 获得邮件主题
     */
    private String getSubject() throws MessagingException {
        return getSubject(this.currentMessage);
    }

    private String getSubject(Message mimeMessage) throws MessagingException {
        String subject = "";
        try {
            // 将邮件主题解码
            subject = MimeUtility.decodeText(mimeMessage.getSubject());
            if (subject == null){
                subject = "";
            }
        } catch (Exception exce) {
        }
        return subject;
    }

    /**
     * 获得邮件发送日期
     */
    private Date getSentDate() throws Exception {
        return getSentDate(this.currentMessage);
    }

    private Date getSentDate(Message mimeMessage) throws Exception {
        return mimeMessage.getSentDate();
    }

    /**
     * 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"
     */
    private boolean getReplySign() throws MessagingException {
        return getReplySign(this.currentMessage);
    }

    private boolean getReplySign(Message mimeMessage) throws MessagingException {
        boolean replysign = false;
        String needreply[] = mimeMessage
                .getHeader("Disposition-Notification-To");
        if (needreply != null) {
            replysign = true;
        }
        return replysign;
    }

    /**
     * 获得此邮件的Message-ID
     */
    private String getMessageId() throws MessagingException {
        return getMessageId(this.currentMessage);
    }

    private String getMessageId(Message mimeMessage) throws MessagingException {
        return ((MimeMessage) mimeMessage).getMessageID();
    }

    /**
     * 判断此邮件是否已读，如果未读返回返回false,反之返回true
     */
    private boolean isNew() throws MessagingException {
        return isNew(this.currentMessage);
    }
    private boolean isNew(Message mimeMessage) 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;
                break;
            }
        }
        return isnew;
    }

    /**
     * 判断此邮件是否包含附件
     */
    private boolean isContainAttach() throws Exception {
        return isContainAttach(this.currentMessage);
    }
    private boolean isContainAttach(Part part) throws Exception {
        boolean attachflag = false;
        if (part.isMimeType("multipart/*")) {
            // 如果邮件体包含多部分
            Multipart mp = (Multipart) part.getContent();
            // 遍历每部分
            for (int i = 0; i < mp.getCount(); i++) {
                // 获得每部分的主体
                BodyPart bodyPart = mp.getBodyPart(i);
                String disposition = bodyPart.getDisposition();
                if ((disposition != null)
                        && ((disposition.equals(Part.ATTACHMENT)) || (disposition
                                .equals(Part.INLINE)))){
                    attachflag = true;
                } else if (bodyPart.isMimeType("multipart/*")) {
                    attachflag = isContainAttach((Part) bodyPart);
                } else {
                    String contype = bodyPart.getContentType();
                    if (contype.toLowerCase().indexOf("application") != -1){
                        attachflag = true;
                    }
                    if (contype.toLowerCase().indexOf("name") != -1){
                        attachflag = true;
                    }
                }
            }
        } else if (part.isMimeType("message/rfc822")) {
            attachflag = isContainAttach((Part) part.getContent());
        }
        return attachflag;
    }

    
    /**
     * 获得当前邮件
     */
    private void getMail() throws Exception {
        try {
            this.saveMessageAsFile(currentMessage);
            this.parseMessage(currentMessage);
        } catch (IOException e) {
            throw new IOException("保存邮件出错，检查保存路径");
        } catch (MessagingException e) {
            throw new MessagingException("邮件转换出错");
        } catch (Exception e) {
            e.printStackTrace();
            throw new Exception("未知错误");
        }
    }
    
    /**
     * 保存邮件源文件
     */
    private void saveMessageAsFile(Message message) {
        try {
            // 将邮件的ID中尖括号中的部分做为邮件的文件名
            String oriFileName = getInfoBetweenBrackets(this.getMessageId(message)
                    .toString());
            //设置文件后缀名。若是附件则设法取得其文件后缀名作为将要保存文件的后缀名，
            //若是正文部分则用.htm做后缀名
            String emlName = oriFileName;
            String fileNameWidthExtension = this.receiverInfo.getEmailDir()
                    + oriFileName + this.receiverInfo.getEmailFileSuffix();
            File storeFile = new File(fileNameWidthExtension);
            for (int i = 0; storeFile.exists(); i++) {
                emlName = oriFileName + i;
                fileNameWidthExtension = this.receiverInfo.getEmailDir()
                        + emlName + this.receiverInfo.getEmailFileSuffix();
                storeFile = new File(fileNameWidthExtension);
            }
            this.currentEmailFileName = emlName;
            System.out.println("邮件消息的存储路径: " + fileNameWidthExtension);
            // 将邮件消息的内容写入ByteArrayOutputStream流中
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            message.writeTo(baos);
            // 读取邮件消息流中的数据
            StringReader in = new StringReader(baos.toString());
            // 存储到文件
            saveFile(fileNameWidthExtension, in);
        } catch (MessagingException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /*
     * 解析邮件
     */
    private void parseMessage(Message message) throws IOException,
            MessagingException {
        Object content = message.getContent();
        // 处理多部分邮件
        if (content instanceof Multipart) {
            handleMultipart((Multipart) content);
        } else {
            handlePart(message);
        }
    }

    /*
     * 解析Multipart
     */
    private void handleMultipart(Multipart multipart) throws MessagingException,
            IOException {
        for (int i = 0, n = multipart.getCount(); i < n; i++) {
            handlePart(multipart.getBodyPart(i));
        }
    }
    /*
     * 解析指定part,从中提取文件
     */
    private void handlePart(Part part) throws MessagingException, IOException {
        String disposition = part.getDisposition();
        String contentType = part.getContentType();
        String fileNameWidthExtension = "";
        // 获得邮件的内容输入流
        InputStreamReader sbis = new InputStreamReader(part.getInputStream());
        // 没有附件的情况
        if (disposition == null) {
            if ((contentType.length() >= 10)
                    && (contentType.toLowerCase().substring(0, 10)
                            .equals("text/plain"))) {
                fileNameWidthExtension = this.receiverInfo.getAttachmentDir()
                        + this.currentEmailFileName + ".txt";
            } else if ((contentType.length() >= 9) // Check if html
                    && (contentType.toLowerCase().substring(0, 9)
                            .equals("text/html"))) {
                fileNameWidthExtension = this.receiverInfo.getAttachmentDir()
                        + this.currentEmailFileName + ".html";
            } else if ((contentType.length() >= 9) // Check if html
                    && (contentType.toLowerCase().substring(0, 9)
                            .equals("image/gif"))) {
                fileNameWidthExtension = this.receiverInfo.getAttachmentDir()
                        + this.currentEmailFileName + ".gif";
            } else if ((contentType.length() >= 11)
                    && contentType.toLowerCase().substring(0, 11).equals(
                            "multipart/*")) {
//                System.out.println("multipart body: " + contentType);
                handleMultipart((Multipart) part.getContent());
            } else { // Unknown type
//                System.out.println("Other body: " + contentType);
                fileNameWidthExtension = this.receiverInfo.getAttachmentDir()
                        + this.currentEmailFileName + ".txt";
            }
            // 存储内容文件
            System.out.println("保存邮件内容到：" + fileNameWidthExtension);
            saveFile(fileNameWidthExtension, sbis);

            return;
        }

        // 各种有附件的情况
        String name = "";
        if (disposition.equalsIgnoreCase(Part.ATTACHMENT)) {
            name = getFileName(part);
//            System.out.println("Attachment: " + name + " : "
//                    + contentType);
            fileNameWidthExtension = this.receiverInfo.getAttachmentDir() + name;
        } else if (disposition.equalsIgnoreCase(Part.INLINE)) {
            name = getFileName(part);
//            System.out.println("Inline: " + name + " : "
//                    + contentType);
            fileNameWidthExtension = this.receiverInfo.getAttachmentDir() + name;
        } else {
//            System.out.println("Other: " + disposition);
        }
        // 存储各类附件
        if (!fileNameWidthExtension.equals("")) {
            System.out.println("保存邮件附件到：" + fileNameWidthExtension);
            saveFile(fileNameWidthExtension, sbis);
        }
    }
    private String getFileName(Part part) throws MessagingException,
            UnsupportedEncodingException {
        String fileName = part.getFileName();
        fileName = MimeUtility.decodeText(fileName);
        String name = fileName;
        if (fileName != null) {
            int index = fileName.lastIndexOf("/");
            if (index != -1) {
                name = fileName.substring(index + 1);
            }
        }
        return name;
    }
    /**
     * 保存文件内容
     * @param fileName    文件名
     * @param input        输入流
     * @throws IOException
     */
    private void saveFile(String fileName, Reader input) throws IOException {

        // 为了放置文件名重名，在重名的文件名后面天上数字
        File file = new File(fileName);
        // 先取得文件名的后缀
        int lastDot = fileName.lastIndexOf(".");
        String extension = fileName.substring(lastDot);
        fileName = fileName.substring(0, lastDot);
        for (int i = 0; file.exists(); i++) {
            //　如果文件重名，则添加i
            file = new File(fileName + i + extension);
        }
        // 从输入流中读取数据，写入文件输出流
        FileWriter fos = new FileWriter(file);
        BufferedWriter bos = new BufferedWriter(fos);
        BufferedReader bis = new BufferedReader(input);
        int aByte;
        while ((aByte = bis.read()) != -1) {
            bos.write(aByte);
        }
        // 关闭流
        bos.flush();
        bos.close();
        bis.close();
    }

    /**
     * 获得尖括号之间的字符
     * @param str
     * @return
     * @throws Exception
     */
    private String getInfoBetweenBrackets(String str) throws Exception {
        int i, j; //用于标识字符串中的"<"和">"的位置
        if (str == null) {
            str = "error";
            return str;
        }
        i = str.lastIndexOf("<");
        j = str.lastIndexOf(">");
        if (i != -1 && j != -1){
            str = str.substring(i + 1, j);
        }
        return str;
    }

    public static void main(String[] args) throws Exception {
        MailReceiverInfo receiverInfo = new MailReceiverInfo();
        receiverInfo.setMailServerHost("pop.163.com");
        receiverInfo.setMailServerPort("110");
        receiverInfo.setValidate(true);
        receiverInfo.setUserName("***");
        receiverInfo.setPassword("***");
        receiverInfo.setAttachmentDir("C:/temp/mail/");
        receiverInfo.setEmailDir("C:/temp/mail/");

        MailReceiver receiver = new MailReceiver(receiverInfo);
        receiver.receiveAllMail();
    }
}