java使用javamail读取邮箱（收件箱为例）

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.text.SimpleDateFormat;
import java.util.Date;
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.InternetAddress;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeUtility;

/**
 * @author yh
 * 
 */
public class ShowMail {

	private MimeMessage mimeMessage = null;
	private String saveAttachPath = ""; // 附件下载后的存放目录
	private StringBuffer bodyText = new StringBuffer(); // 存放邮件内容的StringBuffer对象
	private String dateFormat = "yy-MM-dd HH:mm"; // 默认的日前显示格式

	/**
	 * 构造函数,初始化一个MimeMessage对象
	 */
	public ShowMail() {
	}

	public ShowMail(MimeMessage mimeMessage) {
		this.mimeMessage = mimeMessage;
		System.out.println("创建一个ReceiveEmail对象....");
	}

	public void setMimeMessage(MimeMessage mimeMessage) {
		this.mimeMessage = mimeMessage;
		System.out.println("设置一个MimeMessage对象...");
	}

	/**
	 * 　*　获得发件人的地址和姓名 　
	 */
	public String getFrom() throws Exception {
		InternetAddress address[] = (InternetAddress[]) mimeMessage.getFrom();
		String from = address[0].getAddress();
		if (from == null) {
			from = "";
			System.out.println("无法知道发送者.");
		}
		String personal = address[0].getPersonal();

		if (personal == null) {
			personal = "";
			System.out.println("无法知道发送者的姓名.");
		}

		String fromAddr = null;
		if (personal != null || from != null) {
			fromAddr = personal + "<" + from + ">";
			System.out.println("发送者是：" + fromAddr);
		} else {
			System.out.println("无法获得发送者信息.");
		}
		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
	 * 　*　"to"----收件人　"cc"---抄送人地址　"bcc"---密送人地址 　
	 */
	public String getMailAddress(String type) 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++) {
					String emailAddr = address[i].getAddress();
					if (emailAddr == null) {
						emailAddr = "";
					} else {
						System.out.println("转换之前的emailAddr: " + emailAddr);
						emailAddr = MimeUtility.decodeText(emailAddr);
						System.out.println("转换之后的emailAddr: " + emailAddr);
					}
					String personal = address[i].getPersonal();
					if (personal == null) {
						personal = "";
					} else {
						System.out.println("转换之前的personal: " + personal);
						personal = MimeUtility.decodeText(personal);
						System.out.println("转换之后的personal: " + personal);
					}
					String compositeto = personal + "<" + emailAddr + ">";
					System.out.println("完整的邮件地址：" + compositeto);
					mailAddr += "," + compositeto;
				}
				mailAddr = mailAddr.substring(1);
			}
		} else {
			throw new Exception("错误的电子邮件类型!");
		}
		return mailAddr;
	}

	/**
	 * 　*　获得邮件主题 　
	 */
	public String getSubject() throws MessagingException {
		String subject = "";
		try {
			System.out.println("转换前的subject：" + mimeMessage.getSubject());
			subject = MimeUtility.decodeText(mimeMessage.getSubject());
			System.out.println("转换后的subject: " + mimeMessage.getSubject());
			if (subject == null) {
				subject = "";
			}
		} catch (Exception exce) {
			exce.printStackTrace();
		}
		return subject;
	}

	/**
	 * 　*　获得邮件发送日期 　
	 */
	public String getSentDate() throws Exception {
		Date sentDate = mimeMessage.getSentDate();
		System.out.println("发送日期 原始类型: " + dateFormat);
		SimpleDateFormat format = new SimpleDateFormat(dateFormat);
		String strSentDate = format.format(sentDate);
		System.out.println("发送日期 可读类型: " + strSentDate);
		return strSentDate;
	}

	/**
	 * 　*　获得邮件正文内容 　
	 */
	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 　　
	 */

	public void getMailContent(Part part) throws Exception {

		String contentType = part.getContentType();
		// 获得邮件的MimeType类型
		System.out.println("邮件的MimeType类型: " + contentType);

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

		boolean conName = false;

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

		System.out.println("邮件内容的类型:　" + contentType);

		if (part.isMimeType("text/plain") && conName == false) {
			// text/plain 类型
			bodyText.append((String) part.getContent());
		} else if (part.isMimeType("text/html") && conName == false) {
			// text/html 类型
			bodyText.append((String) part.getContent());
		} else if (part.isMimeType("multipart/*")) {
			// multipart/*
			Multipart multipart = (Multipart) part.getContent();
			int counts = multipart.getCount();
			for (int i = 0; i < counts; i++) {
				getMailContent(multipart.getBodyPart(i));
			}
		} else if (part.isMimeType("message/rfc822")) {
			// message/rfc822
			getMailContent((Part) part.getContent());
		} else {

		}
	}

	/**
	 * 　　*　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" 　
	 */
	public boolean getReplySign() throws MessagingException {

		boolean replySign = false;

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

		if (needReply != null) {
			replySign = true;
		}
		if (replySign) {
			System.out.println("该邮件需要回复");
		} else {
			System.out.println("该邮件不需要回复");
		}
		return replySign;
	}

	/**
	 *　获得此邮件的Message-ID 　　
	 */
	public String getMessageId() throws MessagingException {
		String messageID = mimeMessage.getMessageID();
		System.out.println("邮件ID: " + messageID);
		return messageID;
	}

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

	/**
	 * 判断此邮件是否包含附件
	 */
	public boolean isContainAttach(Part part) throws Exception {
		boolean attachFlag = false;
		// String contentType = part.getContentType();
		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 ((disposition != null)
						&& ((disposition.equals(Part.ATTACHMENT)) || (disposition
								.equals(Part.INLINE))))
					attachFlag = true;
				else if (mPart.isMimeType("multipart/*")) {
					attachFlag = isContainAttach((Part) mPart);
				} else {
					String conType = mPart.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;
	}

	/**
	 * 　*　保存附件 　
	 */

	public void 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 mPart = mp.getBodyPart(i);
				String disposition = mPart.getDisposition();
				if ((disposition != null)
						&& ((disposition.equals(Part.ATTACHMENT)) || (disposition
								.equals(Part.INLINE)))) {
					fileName = mPart.getFileName();
					if (fileName.toLowerCase().indexOf("gb2312") != -1) {
						fileName = MimeUtility.decodeText(fileName);
					}
					saveFile(fileName, mPart.getInputStream());
				} else if (mPart.isMimeType("multipart/*")) {
					saveAttachMent(mPart);
				} else {
					fileName = mPart.getFileName();
					if ((fileName != null)
							&& (fileName.toLowerCase().indexOf("GB2312") != -1)) {
						fileName = MimeUtility.decodeText(fileName);
						saveFile(fileName, mPart.getInputStream());
					}
				}
			}
		} else if (part.isMimeType("message/rfc822")) {
			saveAttachMent((Part) part.getContent());
		}
	}

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

	/**
	 * 　*　设置日期显示格式 　
	 */
	public void setDateFormat(String format) throws Exception {
		this.dateFormat = format;
	}

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

	/**
	 * 　*　真正的保存附件到指定目录里 　
	 */
	private void saveFile(String fileName, InputStream in) throws Exception {
		String osName = System.getProperty("os.name");
		String storeDir = getAttachPath();
		String separator = "";
		if (osName == null) {
			osName = "";
		}
		if (osName.toLowerCase().indexOf("win") != -1) {
			separator = "\";
			if (storeDir == null || storeDir.equals(""))
				storeDir = "c:\tmp";
		} else {
			separator = "/";
			storeDir = "/tmp";
		}
		File storeFile = new File(storeDir + separator + fileName);
		System.out.println("附件的保存地址:　" + storeFile.toString());
		// for(int　i=0;storefile.exists();i++){
		// storefile　=　new　File(storedir+separator+fileName+i);
		// }
		BufferedOutputStream bos = null;
		BufferedInputStream bis = null;

		try {
			bos = new BufferedOutputStream(new FileOutputStream(storeFile));
			bis = new BufferedInputStream(in);
			int c;
			while ((c = bis.read()) != -1) {
				bos.write(c);
				bos.flush();
			}
		} catch (Exception exception) {
			exception.printStackTrace();
			throw new Exception("文件保存失败!");
		} finally {
			bos.close();
			bis.close();
		}
	}

	/**
	 *　ReceiveEmail类测试
	 */
	public static void main(String args[]) throws Exception {
		String host = "pop.sina.com";
		String username = "***";
		String password = "***";

		Properties props = new Properties();
		Session session = Session.getDefaultInstance(props, null);

		Store store = session.getStore("pop3");
		store.connect(host, username, password);

		Folder folder = store.getFolder("INBOX");
		folder.open(Folder.READ_ONLY);
		Message message[] = folder.getMessages();
		System.out.println("邮件数量:　" + message.length);
		ShowMail re = null;

		for (int i = 0; i < message.length; i++) {
			re = new ShowMail((MimeMessage) message[i]);
			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((Part) message[i]));
			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"));
			re.setDateFormat("yy年MM月dd日　HH:mm");
			System.out.println("邮件　" + i + "　发送时间:　" + re.getSentDate());
			System.out.println("邮件　" + i + "　邮件ID:　" + re.getMessageId());
			re.getMailContent((Part) message[i]);
			System.out.println("邮件　" + i + "　正文内容:　
" + re.getBodyText());
			re.setAttachPath("e:\");
			re.saveAttachMent((Part) message[i]);
		}
	}
}

javamail.jar   下载链接