JavaMail学习笔记（四）、使用POP3协议接收并解析电子邮件（全）

不念不忘少年蓝@ 2022-06-10 00:22 324阅读 0赞

package org.yangxin.study.jm;
 
 import java.io.BufferedInputStream;
 import java.io.BufferedOutputStream;
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.UnsupportedEncodingException;
 import java.text.SimpleDateFormat;
 import java.util.Date;
 import java.util.Properties;
 
 import javax.mail.Address;
 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.MimeMultipart;
 import javax.mail.internet.MimeUtility;
 
 /**
 * 使用POP3协议接收邮件
 */
 public class POP3ReceiveMailTest {
 	
 	public static void main(String[] args) throws Exception {
 		receive();
 	}
 	
 	/**
 	 * 接收邮件
 	 */
 	public static void receive() throws Exception {
 		// 准备连接服务器的会话信息
 		Properties props = new Properties();
 		props.setProperty("mail.store.protocol", "pop3");		// 协议
 		props.setProperty("mail.pop3.port", "110");				// 端口
 		props.setProperty("mail.pop3.host", "pop3.163.com");	// pop3服务器
 		
 		// 创建Session实例对象
 		Session session = Session.getInstance(props);
 		Store store = session.getStore("pop3");
 		store.connect("xyang0917@163.com", "123456abc");
 		
 		// 获得收件箱
 		Folder folder = store.getFolder("INBOX");
 		/* Folder.READ_ONLY：只读权限
 		 * Folder.READ_WRITE：可读可写（可以修改邮件的状态）
 		 */
 		folder.open(Folder.READ_WRITE);	//打开收件箱
 		
 		// 由于POP3协议无法获知邮件的状态,所以getUnreadMessageCount得到的是收件箱的邮件总数
 		System.out.println("未读邮件数: " + folder.getUnreadMessageCount());
 		
 		// 由于POP3协议无法获知邮件的状态,所以下面得到的结果始终都是为0
 		System.out.println("删除邮件数: " + folder.getDeletedMessageCount());
 		System.out.println("新邮件: " + folder.getNewMessageCount());
 		
 		// 获得收件箱中的邮件总数
 		System.out.println("邮件总数: " + folder.getMessageCount());
 		
 		// 得到收件箱中的所有邮件,并解析
 		Message[] messages = folder.getMessages();
 		parseMessage(messages);
 		
 		//释放资源
 		folder.close(true);
 		store.close();
 	}
 	
 	/**
 	 * 解析邮件
 	 * @param messages 要解析的邮件列表
 	 */
 	public static void parseMessage(Message ...messages) throws MessagingException, IOException {
 		if (messages == null || messages.length < 1) 
 			throw new MessagingException("未找到要解析的邮件!");
 		
 		// 解析所有邮件
 		for (int i = 0, count = messages.length; i < count; i++) {
 			MimeMessage msg = (MimeMessage) messages[i];
 			System.out.println("------------------解析第" + msg.getMessageNumber() + "封邮件-------------------- ");
 			System.out.println("主题: " + getSubject(msg));
 			System.out.println("发件人: " + getFrom(msg));
 			System.out.println("收件人：" + getReceiveAddress(msg, null));
 			System.out.println("发送时间：" + getSentDate(msg, null));
 			System.out.println("是否已读：" + isSeen(msg));
 			System.out.println("邮件优先级：" + getPriority(msg));
 			System.out.println("是否需要回执：" + isReplySign(msg));
 			System.out.println("邮件大小：" + msg.getSize() * 1024 + "kb");
 			boolean isContainerAttachment = isContainAttachment(msg);
 			System.out.println("是否包含附件：" + isContainerAttachment);
 			if (isContainerAttachment) {
 				saveAttachment(msg, "c:\\mailtmp\\"+msg.getSubject() + "_"); //保存附件
 			} 
 			StringBuffer content = new StringBuffer(30);
 			getMailTextContent(msg, content);
 			System.out.println("邮件正文：" + (content.length() > 100 ? content.substring(0,100) + "..." : content));
 			System.out.println("------------------第" + msg.getMessageNumber() + "封邮件解析结束-------------------- ");
 			System.out.println();
 		}
 	}
 	
 	/**
 	 * 获得邮件主题
 	 * @param msg 邮件内容
 	 * @return 解码后的邮件主题
 	 */
 	public static String getSubject(MimeMessage msg) throws UnsupportedEncodingException, MessagingException {
 		return MimeUtility.decodeText(msg.getSubject());
 	}
 	
 	/**
 	 * 获得邮件发件人
 	 * @param msg 邮件内容
 	 * @return 姓名 <Email地址>
 	 * @throws MessagingException
 	 * @throws UnsupportedEncodingException 
 	 */
 	public static String getFrom(MimeMessage msg) throws MessagingException, UnsupportedEncodingException {
 		String from = "";
 		Address[] froms = msg.getFrom();
 		if (froms.length < 1)
 			throw new MessagingException("没有发件人!");
 		
 		InternetAddress address = (InternetAddress) froms[0];
 		String person = address.getPersonal();
 		if (person != null) {
 			person = MimeUtility.decodeText(person) + " ";
 		} else {
 			person = "";
 		}
 		from = person + "<" + address.getAddress() + ">";
 		
 		return from;
 	}
 	
 	/**
 	 * 根据收件人类型，获取邮件收件人、抄送和密送地址。如果收件人类型为空，则获得所有的收件人
 	 * Message.RecipientType.TO 收件人
 	 * Message.RecipientType.CC 抄送
 	 * Message.RecipientType.BCC 密送
 	 * @param msg 邮件内容
 	 * @param type 收件人类型
 	 * @return 收件人1 <邮件地址1>, 收件人2 <邮件地址2>, ...
 	 * @throws MessagingException
 	 */
 	public static String getReceiveAddress(MimeMessage msg, Message.RecipientType type) throws MessagingException {
 		StringBuffer receiveAddress = new StringBuffer();
 		Address[] addresss = null;
 		if (type == null) {
 			addresss = msg.getAllRecipients();
 		} else {
 			addresss = msg.getRecipients(type);
 		}
 		
 		if (addresss == null || addresss.length < 1)
 			throw new MessagingException("没有收件人!");
 		for (Address address : addresss) {
 			InternetAddress internetAddress = (InternetAddress)address;
 			receiveAddress.append(internetAddress.toUnicodeString()).append(",");
 		}
 		
 		receiveAddress.deleteCharAt(receiveAddress.length()-1);	//删除最后一个逗号
 		
 		return receiveAddress.toString();
 	}
 	
 	/**
 	 * 获得邮件发送时间
 	 * @param msg 邮件内容
 	 * @return yyyy年mm月dd日 星期X HH:mm
 	 * @throws MessagingException
 	 */
 	public static String getSentDate(MimeMessage msg, String pattern) throws MessagingException {
 		Date receivedDate = msg.getSentDate();
 		if (receivedDate == null)
 			return "";
 		
 		if (pattern == null || "".equals(pattern))
 			pattern = "yyyy年MM月dd日 E HH:mm ";
 		
 		return new SimpleDateFormat(pattern).format(receivedDate);
 	}
 	
 	/**
 	 * 判断邮件中是否包含附件
 	 * @param msg 邮件内容
 	 * @return 邮件中存在附件返回true，不存在返回false
 	 * @throws MessagingException
 	 * @throws IOException
 	 */
 	public static boolean isContainAttachment(Part part) throws MessagingException, IOException {
 		boolean flag = false;
 		if (part.isMimeType("multipart/*")) {
 			MimeMultipart multipart = (MimeMultipart) part.getContent();
 			int partCount = multipart.getCount();
 			for (int i = 0; i < partCount; i++) {
 				BodyPart bodyPart = multipart.getBodyPart(i);
 				String disp = bodyPart.getDisposition();
 				if (disp != null && (disp.equalsIgnoreCase(Part.ATTACHMENT) || disp.equalsIgnoreCase(Part.INLINE))) {
 					flag = true;
 				} else if (bodyPart.isMimeType("multipart/*")) {
 					flag = isContainAttachment(bodyPart);
 				} else {
 					String contentType = bodyPart.getContentType();
 					if (contentType.indexOf("application") != -1) {
 						flag = true;
 					} 
 					
 					if (contentType.indexOf("name") != -1) {
 						flag = true;
 					} 
 				}
 				
 				if (flag) break;
 			}
 		} else if (part.isMimeType("message/rfc822")) {
 			flag = isContainAttachment((Part)part.getContent());
 		}
 		return flag;
 	}
 	
 	/**
 	 * 判断邮件是否已读
 	 * @param msg 邮件内容
 	 * @return 如果邮件已读返回true,否则返回false
 	 * @throws MessagingException 
 	 */
 	public static boolean isSeen(MimeMessage msg) throws MessagingException {
 		return msg.getFlags().contains(Flags.Flag.SEEN);
 	}
 	
 	/**
 	 * 判断邮件是否需要阅读回执
 	 * @param msg 邮件内容
 	 * @return 需要回执返回true,否则返回false
 	 * @throws MessagingException
 	 */
 	public static boolean isReplySign(MimeMessage msg) throws MessagingException {
 		boolean replySign = false;
 		String[] headers = msg.getHeader("Disposition-Notification-To");
 		if (headers != null)
 			replySign = true;
 		return replySign;
 	}
 	
 	/**
 	 * 获得邮件的优先级
 	 * @param msg 邮件内容
 	 * @return 1(High):紧急 3:普通(Normal) 5:低(Low)
 	 * @throws MessagingException 
 	 */
 	public static String getPriority(MimeMessage msg) throws MessagingException {
 		String priority = "普通";
 		String[] headers = msg.getHeader("X-Priority");
 		if (headers != null) {
 			String headerPriority = headers[0];
 			if (headerPriority.indexOf("1") != -1 || headerPriority.indexOf("High") != -1)
 				priority = "紧急";
 			else if (headerPriority.indexOf("5") != -1 || headerPriority.indexOf("Low") != -1)
 				priority = "低";
 			else
 				priority = "普通";
 		}
 		return priority;
 	} 
 	
 	/**
 	 * 获得邮件文本内容
 	 * @param part 邮件体
 	 * @param content 存储邮件文本内容的字符串
 	 * @throws MessagingException
 	 * @throws IOException
 	 */
 	public static void getMailTextContent(Part part, StringBuffer content) throws MessagingException, IOException {
 		//如果是文本类型的附件，通过getContent方法可以取到文本内容，但这不是我们需要的结果，所以在这里要做判断
 		boolean isContainTextAttach = part.getContentType().indexOf("name") > 0;	
 		if (part.isMimeType("text/*") && !isContainTextAttach) {
 			content.append(part.getContent().toString());
 		} else if (part.isMimeType("message/rfc822")) {	
 			getMailTextContent((Part)part.getContent(),content);
 		} else if (part.isMimeType("multipart/*")) {
 			Multipart multipart = (Multipart) part.getContent();
 			int partCount = multipart.getCount();
 			for (int i = 0; i < partCount; i++) {
 				BodyPart bodyPart = multipart.getBodyPart(i);
 				getMailTextContent(bodyPart,content);
 			}
 		}
 	}
 	
 	/**
 	 * 保存附件
 	 * @param part 邮件中多个组合体中的其中一个组合体
 	 * @param destDir 附件保存目录
 	 * @throws UnsupportedEncodingException
 	 * @throws MessagingException
 	 * @throws FileNotFoundException
 	 * @throws IOException
 	 */
 	public static void saveAttachment(Part part, String destDir) throws UnsupportedEncodingException, MessagingException,
 			FileNotFoundException, IOException {
 		if (part.isMimeType("multipart/*")) {
 			Multipart multipart = (Multipart) part.getContent();	//复杂体邮件
 			//复杂体邮件包含多个邮件体
 			int partCount = multipart.getCount();
 			for (int i = 0; i < partCount; i++) {
 				//获得复杂体邮件中其中一个邮件体
 				BodyPart bodyPart = multipart.getBodyPart(i);
 				//某一个邮件体也有可能是由多个邮件体组成的复杂体
 				String disp = bodyPart.getDisposition();
 				if (disp != null && (disp.equalsIgnoreCase(Part.ATTACHMENT) || disp.equalsIgnoreCase(Part.INLINE))) {
 					InputStream is = bodyPart.getInputStream();
 					saveFile(is, destDir, decodeText(bodyPart.getFileName()));
 				} else if (bodyPart.isMimeType("multipart/*")) {
 					saveAttachment(bodyPart,destDir);
 				} else {
 					String contentType = bodyPart.getContentType();
 					if (contentType.indexOf("name") != -1 || contentType.indexOf("application") != -1) {
 						saveFile(bodyPart.getInputStream(), destDir, decodeText(bodyPart.getFileName()));
 					}
 				}
 			}
 		} else if (part.isMimeType("message/rfc822")) {
 			saveAttachment((Part) part.getContent(),destDir);
 		}
 	}
 	
 	/**
 	 * 读取输入流中的数据保存至指定目录
 	 * @param is 输入流
 	 * @param fileName 文件名
 	 * @param destDir 文件存储目录
 	 * @throws FileNotFoundException
 	 * @throws IOException
 	 */
 	private static void saveFile(InputStream is, String destDir, String fileName)
 			throws FileNotFoundException, IOException {
 		BufferedInputStream bis = new BufferedInputStream(is);
 		BufferedOutputStream bos = new BufferedOutputStream(
 				new FileOutputStream(new File(destDir + fileName)));
 		int len = -1;
 		while ((len = bis.read()) != -1) {
 			bos.write(len);
 			bos.flush();
 		}
 		bos.close();
 		bis.close();
 	}
 	
 	/**
 	 * 文本解码
 	 * @param encodeText 解码MimeUtility.encodeText(String text)方法编码后的文本
 	 * @return 解码后的文本
 	 * @throws UnsupportedEncodingException
 	 */
 	public static String decodeText(String encodeText) throws UnsupportedEncodingException {
 		if (encodeText == null || "".equals(encodeText)) {
 			return "";
 		} else {
 			return MimeUtility.decodeText(encodeText);
 		}
 	}
 }

***测试结果：***

![1340045073_6624.jpg][]

[1340045073_6624.jpg]: https://img-my.csdn.net/uploads/201206/19/1340045073_6624.jpg