JavaMail教程(三)-接收邮件

1.接收邮件

1.1使用POP3接收邮件

1.1.1输出收件箱信息

package org.ygy.demo;import java.util.Properties;import javax.mail.Folder;import javax.mail.MessagingException;import javax.mail.NoSuchProviderException;import javax.mail.Session;import javax.mail.Store;public class ReceiveMail {public static final String HOST = "pop.126.com";//服务器地址public static final String PROTOCOL = "pop3";//协议public static final String PORT = "110";//pop默认端口为110public static final String USER = "[e-mail]";//账户public static final String PASSWORD = "xxx";//密码/** * 输出收件箱的基本信息 */public void displayFolderInfo() {Properties props = new Properties();props.put("mail.pop3.host", ReceiveMail.HOST);//设置服务器地址props.put("mail.store.protocol" , ReceiveMail.PROTOCOL);//设置协议props.put("mail.pop3.port", "110");//设置端口Session session = Session.getDefaultInstance(props);Store store = null;Folder folder = null;try {store = session.getStore();store.connect(HOST , USER , PASSWORD);/* * POP3 supports only a single folder named "INBOX". * POP协议的话，这里只能是INBOX */folder = store.getFolder("INBOX");folder.open(Folder.READ_ONLY);//以只读方式打开收件箱System.out.println("邮件总数：" + folder.getMessageCount());//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0System.out.println("删除邮件数：" + folder.getDeletedMessageCount());System.out.println("新邮件数：" + folder.getNewMessageCount());} catch (NoSuchProviderException e) {e.printStackTrace();} catch (MessagingException e) {e.printStackTrace();} finally {try {folder.close(false);store.close();} catch (MessagingException e) {e.printStackTrace();}}}public static void main(String[] args) {ReceiveMail receive = new ReceiveMail();receive.displayFolderInfo();}}

结果显示如下图：

这时，你可以通过浏览器登录“126邮箱”删除几封邮件，再运行测试一下，数据都是正确的。126邮箱默认都打开了POP/SMTP功能，可以设置的。

注：126邮箱比较好用，之前使用QQ邮箱时，获取的”邮件总数“总是不对，结果显示只有16封，但是用浏览器登录QQ邮箱，可以看到一共有200多封，不知道还需要设置什么。输出邮件内容之后，发现好像只有2013年的，。

1.1.2输出邮件信息

package org.ygy.demo;import java.io.BufferedInputStream;import java.io.BufferedOutputStream;import java.io.File;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.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.MimeMultipart;import javax.mail.internet.MimeUtility;public class ReceiveMail {public static final String HOST = "pop.126.com";//服务器地址public static final String PROTOCOL = "pop3";//协议public static final String PORT = "110";//pop默认端口为110public static final String USER = "[e-mail]";//账户public static final String PASSWORD = "xxx";//密码public static final String DEFAULT_PATTERN = "yyyy年MM月dd日 E HH:mm";public static Session session = null;/** * 输出收件箱的基本信息 */public void displayFolderInfo() {Session session = getSession();Store store = null;Folder folder = null;try {store = session.getStore();store.connect(HOST , USER , PASSWORD);/* * POP3 supports only a single folder named "INBOX". * POP协议的话，这里只能是INBOX */folder = store.getFolder("INBOX");folder.open(Folder.READ_ONLY);//以只读方式打开收件箱System.out.println("邮件总数：" + folder.getMessageCount());//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0System.out.println("删除邮件数：" + folder.getDeletedMessageCount());System.out.println("新邮件数：" + folder.getNewMessageCount());} catch (NoSuchProviderException e) {e.printStackTrace();} catch (MessagingException e) {e.printStackTrace();} finally {try {folder.close(false);store.close();} catch (MessagingException e) {e.printStackTrace();}}}/** * 获取Session * @return */public static Session getSession() {if(session == null) {Properties props = new Properties();props.put("mail.pop3.host", ReceiveMail.HOST);//设置服务器地址props.put("mail.store.protocol" , ReceiveMail.PROTOCOL);//设置协议props.put("mail.pop3.port", "110");//设置端口session = Session.getDefaultInstance(props);}return session;}/** * 输出邮件的信息 */public void displayMessageInfo() {Session session = getSession();Store store = null;Folder folder = null;try {store = session.getStore();store.connect(HOST , USER , PASSWORD);folder = store.getFolder("INBOX");//POP协议的话，这里只能是INBOXfolder.open(Folder.READ_ONLY);//以只读方式打开收件箱parseMessages(folder.getMessages());} catch (NoSuchProviderException e) {e.printStackTrace();} catch (MessagingException e) {e.printStackTrace();} catch (UnsupportedEncodingException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} finally {try {folder.close(false);store.close();} catch (MessagingException e) {e.printStackTrace();}}}/** * 解析邮件 * @param messages * @throws MessagingException  * @throws IOException  */public void parseMessages(Message[] messages) throws MessagingException, IOException {if(messages.length < 1 || messages == null) {System.out.println("没有邮件");} else {for(int i = 0; i < messages.length; i++) {MimeMessage each = (MimeMessage) messages[i];System.out.println("------------------解析第" + each.getMessageNumber() + "封邮件-------------------- ");             System.out.println("主题: " + getSubject(each));             System.out.println("发件人: " + getFrom(each));             System.out.println("收件人：" + getReceiveAddress(each, null));             System.out.println("发送时间：" + getSentDate(each, ReceiveMail.DEFAULT_PATTERN));             System.out.println("是否已读：" + isSeen(each));             System.out.println("邮件优先级：" + getPriority(each));             System.out.println("是否需要回执：" + isReplySign(each));             System.out.println("邮件大小：" + each.getSize() + "b");             boolean isContainerAttachment = isContainAttachment(each);             System.out.println("是否包含附件：" + isContainerAttachment);             if (isContainerAttachment) {                 saveAttachment(each, "F:\\mailtmp\\"+each.getSubject() + "_"); //保存附件             }              StringBuffer content = new StringBuffer(30);             getMailTextContent(each, content);             System.out.println("邮件正文：" + (content.length() > 100 ? content.substring(0,100) + "..." : content));             System.out.println("------------------第" + each.getMessageNumber() + "封邮件解析结束-------------------- ");             System.out.println(); }}}/** * 获取邮件文本内容 * @param part 邮件体 * @param content 存储邮件文本内容的字符串 * @throws MessagingException * @throws IOException */private 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 IOException */private void saveAttachment(Part part, String destDir) throws UnsupportedEncodingException, MessagingException, 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 destDir 文件名 * @param fileName 文件存储目录 * @throws IOException */private void saveFile(InputStream is, String destDir, String fileName) throws 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 */private String decodeText(String encodeText) throws UnsupportedEncodingException {if (encodeText == null || "".equals(encodeText)) {             return "";         } else {             return MimeUtility.decodeText(encodeText);         } }/** * 判断邮件中是否包含附件 * @param part邮件 * @return邮件中存在附件返回true，不存在返回false * @throws MessagingException * @throws IOException */private 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;}/** * 判断邮件是否需要回执 * @param msg邮件 * @return 需要回执返回true,否则返回false * @throws MessagingException */private 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 * @return1(High):紧急  3:普通(Normal)  5:低(Low) * @throws MessagingException */private 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; }/** * 判断邮件是否已读（使用POP3的话，这里应该都是未读） * @param msg邮件 * @return已读-true；未读-false * @throws MessagingException */private boolean isSeen(MimeMessage msg) throws MessagingException {return msg.getFlags().contains(Flags.Flag.SEEN);}/** * 获取邮件发送时间 * @param msg邮件 * @param pattern日期格式 * @return * @throws MessagingException */private String getSentDate(MimeMessage msg, String pattern)throws MessagingException {String sentDate = "";Date receivedDate = msg.getSentDate();if(receivedDate != null) {sentDate = new SimpleDateFormat(pattern).format(receivedDate);} else {sentDate = "没有邮件发送时间!";}return sentDate;}/** * 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 * @param msg邮件 * @param type 收件人类型 * Message.RecipientType.TO  收件人 * Message.RecipientType.CC  抄送 * Message.RecipientType.BCC 密送 * @return * @throws MessagingException */private 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) {receiveAddress.append("没有收件人");} else {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(); }/** * 获取发件人 * @param msg 邮件 * @return 姓名 <邮箱地址> * @throws MessagingException * @throws UnsupportedEncodingException */private String getFrom(MimeMessage msg) throws MessagingException, UnsupportedEncodingException {Address[] froms = msg.getFrom();StringBuilder  from = new StringBuilder("");if (froms.length < 1) {from.append("没有收件人");} else {InternetAddress address = (InternetAddress) froms[0];from.append((address.getPersonal() == null)? "" : MimeUtility.decodeText(address.getPersonal()));from.append(" <").append(address.getAddress()).append(">");}return from.toString();}/** * 获得邮件主题 * @param msg 邮件 * @return解码后的邮件主题 * @throws UnsupportedEncodingException * @throws MessagingException */private String getSubject(MimeMessage msg) throws UnsupportedEncodingException, MessagingException {return  MimeUtility.decodeText(msg.getSubject());}public static void main(String[] args) {ReceiveMail receive = new ReceiveMail();receive.displayFolderInfo();receive.displayMessageInfo();}}

邮件的附件部分没有仔细研究，代码是从下面的参考文章学习的。

2.参考文章

JavaMail学习笔记（一）、理解邮件传输协议（SMTP、POP3、IMAP、MIME）

JavaMail学习笔记（二）、JavaMail API简介和配置开发环境

JavaMail学习笔记（三）、使用SMTP协议发送电子邮件（全）

JavaMail学习笔记（四）、使用POP3协议接收并解析电子邮件（全）

JavaMail学习笔记（五）、使用IMAP协议接收并解析电子邮件

JavaMail学习笔记（六）、搜索邮件