用Java代码凭借邮箱及账号获取邮箱内容，这个需要不是很常见，笔者是突然有一需求要把邮件内容展示在网页端上，然后不断的百度，遇到了很多坑或者一些资料不全的文档，最终终终于找到了一个质量非常高的代码，这篇文章也是想把这个demo进行收录，防止源文档被删掉。

代码展示

原文作者：一曲破东风@CSDN
代码的注释相对来说是完善的，我就暂时不做完善啦😁，如果有需要欢迎在评论区评论。🤔

  1. import java.io.*;    
  2. import java.text.*;    
  3. import java.util.*;    
  4. import javax.mail.*;    
  5. import javax.mail.internet.*;    
  7. /**   
  8.  * 有一封邮件就需要建立一个ReciveMail对象   
  9.  */   
  10. public class ReciveOneMail {    
  11.     private MimeMessage mimeMessage = null;    
  12.     private String saveAttachPath = ""; //附件下载后的存放目录    
  13.     private StringBuffer bodytext = new StringBuffer();//存放邮件内容    
  14.     private String dateformat = "yy-MM-dd HH:mm"; //默认的日前显示格式    
  16.     public ReciveOneMail(MimeMessage mimeMessage) {    
  17.         this.mimeMessage = mimeMessage;    
  18.     }    
  20.     public void setMimeMessage(MimeMessage mimeMessage) {    
  21.         this.mimeMessage = mimeMessage;    
  22.     }    
  24.     /**   
  25.      * 获得发件人的地址和姓名   
  26.      */   
  27.     public String getFrom() throws Exception {    
  28.         InternetAddress address[] = (InternetAddress[]) mimeMessage.getFrom();    
  29.         String from = address[0].getAddress();    
  30.         if (from == null)    
  31.             from = "";    
  32.         String personal = address[0].getPersonal();    
  33.         if (personal == null)    
  34.             personal = "";    
  35.         String fromaddr = personal + "<" + from + ">";    
  36.         return fromaddr;    
  37.     }    
  39.     /**   
  40.      * 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   
  41.      */   
  42.     public String getMailAddress(String type) throws Exception {    
  43.         String mailaddr = "";    
  44.         String addtype = type.toUpperCase();    
  45.         InternetAddress[] address = null;    
  46.         if (addtype.equals("TO") || addtype.equals("CC")|| addtype.equals("BCC")) {    
  47.             if (addtype.equals("TO")) {    
  48.                 address = (InternetAddress[]) mimeMessage.getRecipients(Message.RecipientType.TO);    
  49.             } else if (addtype.equals("CC")) {    
  50.                 address = (InternetAddress[]) mimeMessage.getRecipients(Message.RecipientType.CC);    
  51.             } else {    
  52.                 address = (InternetAddress[]) mimeMessage.getRecipients(Message.RecipientType.BCC);    
  53.             }    
  54.             if (address != null) {    
  55.                 for (int i = 0; i < address.length; i++) {    
  56.                     String email = address[i].getAddress();    
  57.                     if (email == null)    
  58.                         email = "";    
  59.                     else {    
  60.                         email = MimeUtility.decodeText(email);    
  61.                     }    
  62.                     String personal = address[i].getPersonal();    
  63.                     if (personal == null)    
  64.                         personal = "";    
  65.                     else {    
  66.                         personal = MimeUtility.decodeText(personal);    
  67.                     }    
  68.                     String compositeto = personal + "<" + email + ">";    
  69.                     mailaddr += "," + compositeto;    
  70.                 }    
  71.                 mailaddr = mailaddr.substring(1);    
  72.             }    
  73.         } else {    
  74.             throw new Exception("Error emailaddr type!");    
  75.         }    
  76.         return mailaddr;    
  77.     }    
  79.     /**   
  80.      * 获得邮件主题   
  81.      */   
  82.     public String getSubject() throws MessagingException {    
  83.         String subject = "";    
  84.         try {    
  85.             subject = MimeUtility.decodeText(mimeMessage.getSubject());    
  86.             if (subject == null)    
  87.                 subject = "";    
  88.         } catch (Exception exce) {}    
  89.         return subject;    
  90.     }    
  92.     /**   
  93.      * 获得邮件发送日期   
  94.      */   
  95.     public String getSentDate() throws Exception {    
  96.         Date sentdate = mimeMessage.getSentDate();    
  97.         SimpleDateFormat format = new SimpleDateFormat(dateformat);    
  98.         return format.format(sentdate);    
  99.     }    
  101.     /**   
  102.      * 获得邮件正文内容   
  103.      */   
  104.     public String getBodyText() {    
  105.         return bodytext.toString();    
  106.     }    
  108.     /**   
  109.      * 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   
  110.      */   
  111.     public void getMailContent(Part part) throws Exception {    
  112.         String contenttype = part.getContentType();    
  113.         int nameindex = contenttype.indexOf("name");    
  114.         boolean conname = false;    
  115.         if (nameindex != -1)    
  116.             conname = true;    
  117.         System.out.println("CONTENTTYPE: " + contenttype);    
  118.         if (part.isMimeType("text/plain") && !conname) {    
  119.             bodytext.append((String) part.getContent());    
  120.         } else if (part.isMimeType("text/html") && !conname) {    
  121.             bodytext.append((String) part.getContent());    
  122.         } else if (part.isMimeType("multipart/*")) {    
  123.             Multipart multipart = (Multipart) part.getContent();    
  124.             int counts = multipart.getCount();    
  125.             for (int i = 0; i < counts; i++) {    
  126.                 getMailContent(multipart.getBodyPart(i));    
  127.             }    
  128.         } else if (part.isMimeType("message/rfc822")) {    
  129.             getMailContent((Part) part.getContent());    
  130.         } else {}    
  131.     }    
  133.     /**    
  134.      * 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"   
  135.      */    
  136.     public boolean getReplySign() throws MessagingException {    
  137.         boolean replysign = false;    
  138.         String needreply[] = mimeMessage    
  139.                 .getHeader("Disposition-Notification-To");    
  140.         if (needreply != null) {    
  141.             replysign = true;    
  142.         }    
  143.         return replysign;    
  144.     }    
  146.     /**   
  147.      * 获得此邮件的Message-ID   
  148.      */   
  149.     public String getMessageId() throws MessagingException {    
  150.         return mimeMessage.getMessageID();    
  151.     }    
  153.     /**   
  154.      * 【判断此邮件是否已读，如果未读返回返回false,反之返回true】   
  155.      */   
  156.     public boolean isNew() throws MessagingException {    
  157.         boolean isnew = false;    
  158.         Flags flags = ((Message) mimeMessage).getFlags();    
  159.         Flags.Flag[] flag = flags.getSystemFlags();    
  160.         System.out.println("flags's length: " + flag.length);    
  161.         for (int i = 0; i < flag.length; i++) {    
  162.             if (flag[i] == Flags.Flag.SEEN) {    
  163.                 isnew = true;    
  164.                 System.out.println("seen Message.......");    
  165.                 break;    
  166.             }    
  167.         }    
  168.         return isnew;    
  169.     }    
  171.     /**   
  172.      * 判断此邮件是否包含附件   
  173.      */   
  174.     public boolean isContainAttach(Part part) throws Exception {    
  175.         boolean attachflag = false;    
  176.         String contentType = part.getContentType();    
  177.         if (part.isMimeType("multipart/*")) {    
  178.             Multipart mp = (Multipart) part.getContent();    
  179.             for (int i = 0; i < mp.getCount(); i++) {    
  180.                 BodyPart mpart = mp.getBodyPart(i);    
  181.                 String disposition = mpart.getDisposition();    
  182.                 if ((disposition != null)    
  183.                         && ((disposition.equals(Part.ATTACHMENT)) || (disposition    
  184.                                 .equals(Part.INLINE))))    
  185.                     attachflag = true;    
  186.                 else if (mpart.isMimeType("multipart/*")) {    
  187.                     attachflag = isContainAttach((Part) mpart);    
  188.                 } else {    
  189.                     String contype = mpart.getContentType();    
  190.                     if (contype.toLowerCase().indexOf("application") != -1)    
  191.                         attachflag = true;    
  192.                     if (contype.toLowerCase().indexOf("name") != -1)    
  193.                         attachflag = true;    
  194.                 }    
  195.             }    
  196.         } else if (part.isMimeType("message/rfc822")) {    
  197.             attachflag = isContainAttach((Part) part.getContent());    
  198.         }    
  199.         return attachflag;    
  200.     }    
  202.     /**    
  203.      * 【保存附件】    
  204.      */    
  205.     public void saveAttachMent(Part part) throws Exception {    
  206.         String fileName = "";    
  207.         if (part.isMimeType("multipart/*")) {    
  208.             Multipart mp = (Multipart) part.getContent();    
  209.             for (int i = 0; i < mp.getCount(); i++) {    
  210.                 BodyPart mpart = mp.getBodyPart(i);    
  211.                 String disposition = mpart.getDisposition();    
  212.                 if ((disposition != null)    
  213.                         && ((disposition.equals(Part.ATTACHMENT)) || (disposition    
  214.                                 .equals(Part.INLINE)))) {    
  215.                     fileName = mpart.getFileName();    
  216.                     if (fileName.toLowerCase().indexOf("gb2312") != -1) {    
  217.                         fileName = MimeUtility.decodeText(fileName);    
  218.                     }    
  219.                     saveFile(fileName, mpart.getInputStream());    
  220.                 } else if (mpart.isMimeType("multipart/*")) {    
  221.                     saveAttachMent(mpart);    
  222.                 } else {    
  223.                     fileName = mpart.getFileName();    
  224.                     if ((fileName != null)    
  225.                             && (fileName.toLowerCase().indexOf("GB2312") != -1)) {    
  226.                         fileName = MimeUtility.decodeText(fileName);    
  227.                         saveFile(fileName, mpart.getInputStream());    
  228.                     }    
  229.                 }    
  230.             }    
  231.         } else if (part.isMimeType("message/rfc822")) {    
  232.             saveAttachMent((Part) part.getContent());    
  233.         }    
  234.     }    
  236.     /**    
  237.      * 【设置附件存放路径】    
  238.      */    
  240.     public void setAttachPath(String attachpath) {    
  241.         this.saveAttachPath = attachpath;    
  242.     }    
  244.     /**   
  245.      * 【设置日期显示格式】   
  246.      */   
  247.     public void setDateFormat(String format) throws Exception {    
  248.         this.dateformat = format;    
  249.     }    
  251.     /**   
  252.      * 【获得附件存放路径】   
  253.      */   
  254.     public String getAttachPath() {    
  255.         return saveAttachPath;    
  256.     }    
  258.     /**   
  259.      * 【真正的保存附件到指定目录里】   
  260.      */   
  261.     private void saveFile(String fileName, InputStream in) throws Exception {    
  262.         String osName = System.getProperty("os.name");    
  263.         String storedir = getAttachPath();    
  264.         String separator = "";    
  265.         if (osName == null)    
  266.             osName = "";    
  267.         if (osName.toLowerCase().indexOf("win") != -1) {    
  268.             separator = "\\";   
  269.             if (storedir == null || storedir.equals(""))   
  270.                 storedir = "c:\\tmp";   
  271.         } else {   
  272.             separator = "/";   
  273.             storedir = "/tmp";   
  274.         }   
  275.         File storefile = new File(storedir + separator + fileName);   
  276.         System.out.println("storefile's path: " + storefile.toString());   
  277.         // for(int i=0;storefile.exists();i++){   
  278.         // storefile = new File(storedir+separator+fileName+i);   
  279.         // }   
  280.         BufferedOutputStream bos = null;   
  281.         BufferedInputStream bis = null;   
  282.         try {   
  283.             bos = new BufferedOutputStream(new FileOutputStream(storefile));   
  284.             bis = new BufferedInputStream(in);   
  285.             int c;   
  286.             while ((c = bis.read()) != -1) {   
  287.                 bos.write(c);   
  288.                 bos.flush();   
  289.             }   
  290.         } catch (Exception exception) {   
  291.             exception.printStackTrace();   
  292.             throw new Exception("文件保存失败!");   
  293.         } finally {   
  294.             bos.close();   
  295.             bis.close();   
  296.         }   
  297.     }   
  299.     /**   
  300.      * PraseMimeMessage类测试   
  301.      */   
  302.     public static void main(String args[]) throws Exception {   
  303.         Properties props = System.getProperties();   
  304.         props.put("mail.smtp.host", "smtp.163.com");   
  305.         props.put("mail.smtp.auth", "true");   
  306.         Session session = Session.getDefaultInstance(props, null);   
  307.         URLName urln = new URLName("pop3", "pop3.163.com", 110, null,   
  308.                 "xiangzhengyan", "pass");   
  309.         Store store = session.getStore(urln);   
  310.         store.connect();   
  311.         Folder folder = store.getFolder("INBOX");   
  312.         folder.open(Folder.READ_ONLY);   
  313.         Message message[] = folder.getMessages();   
  314.         System.out.println("Messages's length: " + message.length);   
  315.         ReciveOneMail pmm = null;   
  316.         for (int i = 0; i < message.length; i++) {   
  317.             System.out.println("======================");   
  318.             pmm = new ReciveOneMail((MimeMessage) message[i]);   
  319.             System.out.println("Message " + i + " subject: " + pmm.getSubject());   
  320.             System.out.println("Message " + i + " sentdate: "+ pmm.getSentDate());   
  321.             System.out.println("Message " + i + " replysign: "+ pmm.getReplySign());   
  322.             System.out.println("Message " + i + " hasRead: " + pmm.isNew());   
  323.             System.out.println("Message " + i + "  containAttachment: "+ pmm.isContainAttach((Part) message[i]));   
  324.             System.out.println("Message " + i + " form: " + pmm.getFrom());   
  325.             System.out.println("Message " + i + " to: "+ pmm.getMailAddress("to"));   
  326.             System.out.println("Message " + i + " cc: "+ pmm.getMailAddress("cc"));   
  327.             System.out.println("Message " + i + " bcc: "+ pmm.getMailAddress("bcc"));   
  328.             pmm.setDateFormat("yy年MM月dd日 HH:mm");   
  329.             System.out.println("Message " + i + " sentdate: "+ pmm.getSentDate());   
  330.             System.out.println("Message " + i + " Message-ID: "+ pmm.getMessageId());   
  331.             // 获得邮件内容===============   
  332.             pmm.getMailContent((Part) message[i]);   
  333.             System.out.println("Message " + i + " bodycontent: \r\n"   
  334.                     + pmm.getBodyText());   
  335.             pmm.setAttachPath("c:\\");    
  336.             pmm.saveAttachMent((Part) message[i]);    
  337.         }    
  338.     }    
  339. }