java读取邮件

package com.zz.mail;  

import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.util.Properties;
import javax.mail.Address;
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.MimeUtility;  

/**
* 邮件接受测试
*
*/
public class POP3MailReceiverTest {
    public POP3MailReceiverTest() {
        try {
            // 1. 设置连接信息, 生成一个 Session
            String protocol = "pop3";
            boolean isSSL = true;
            String host = "pop.163.com";
            int port = 995;
            String username = "[email protected]";
            String password = "****";

            Properties props = new Properties();
            props.put("mail.pop3.ssl.enable", isSSL);
            props.put("mail.pop3.host", host);
            props.put("mail.pop3.port", port);

            Session session = Session.getDefaultInstance(props);
            // 2. 获取 Store 并连接到服务器
            Store store = session.getStore(protocol);
            store.connect(username, password);
            Folder folder = store.getDefaultFolder();// 默认父目录
            if (folder == null) {
                System.out.println("服务器不可用");
                return;
            }
          /*
           System.out.println("默认信箱名:" + folder.getName()); 

           Folder[] folders = folder.list();// 默认目录列表
           for(int i = 0; i < folders.length; i++) {
               System.out.println(folders[0].getName());
           }
            System.out.println("默认目录下的子目录数: " + folders.length);
            */
            Folder popFolder = folder.getFolder("INBOX");// 获取收件箱
            popFolder.open(Folder.READ_WRITE);// 可读邮件,可以删邮件的模式打开目录
            // 4. 列出来收件箱 下所有邮件
            Message[] messages = popFolder.getMessages();
            // 取出来邮件数
            int msgCount = popFolder.getMessageCount();
            System.out.println("共有邮件: " + msgCount + "封");
            // FetchProfile fProfile = new FetchProfile();// 选择邮件的下载模式,
            // 根据网速选择不同的模式
            // fProfile.add(FetchProfile.Item.ENVELOPE);
            // folder.fetch(messages, fProfile);// 选择性的下载邮件
            // 5. 循环处理每个邮件并实现邮件转为新闻的功能
            for (int i = 0; i < msgCount; i++) {
                // 单个邮件
                System.out.println("第" + i +"邮件开始");
                mailReceiver(messages[i]);
                System.out.println("第" + i +"邮件结束");
               //邮件读取用来校验
                 messages[i].writeTo(new FileOutputStream("D:/pop3MailReceiver"+ i +".eml"));
            }
            // 7. 关闭 Folder 会真正删除邮件, false 不删除
            popFolder.close(true);
            // 8. 关闭 store, 断开网络连接
            store.close();
        } catch (NoSuchProviderException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }  

    /**
     * 解析邮件
     *
     * @param messages 邮件对象
     * @param i
     * @return
     * @throws IOException
     * @throws MessagingException
     * @throws FileNotFoundException
     * @throws UnsupportedEncodingException
     */
    private void mailReceiver(Message msg)throws Exception{
        // 发件人信息
        Address[] froms = msg.getFrom();
        if(froms != null) {
            //System.out.println("发件人信息:" + froms[0]);
            InternetAddress addr = (InternetAddress)froms[0];
            System.out.println("发件人地址:" + addr.getAddress());
            System.out.println("发件人显示名:" + addr.getPersonal());
        }
        System.out.println("邮件主题:" + msg.getSubject());
        // getContent() 是获取包裹内容, Part相当于外包装
        Object o = msg.getContent();
        if(o instanceof Multipart) {
            Multipart multipart = (Multipart) o ;
            reMultipart(multipart);
        } else if (o instanceof Part){
            Part part = (Part) o;
            rePart(part);
        } else {
            System.out.println("类型" + msg.getContentType());
            System.out.println("内容" + msg.getContent());
        }
    }  

    /**
     * @param part 解析内容
     * @throws Exception
     */
    private void rePart(Part part) throws MessagingException,
            UnsupportedEncodingException, IOException, FileNotFoundException {
        if (part.getDisposition() != null) {  

            String strFileNmae = MimeUtility.decodeText(part.getFileName()); //MimeUtility.decodeText解决附件名乱码问题
            System.out.println("发现附件: " +  MimeUtility.decodeText(part.getFileName()));
            System.out.println("内容类型: " + MimeUtility.decodeText(part.getContentType()));
            System.out.println("附件内容:" + part.getContent());
            InputStream in = part.getInputStream();// 打开附件的输入流
            // 读取附件字节并存储到文件中
            java.io.FileOutputStream out = new FileOutputStream(strFileNmae);
            int data;
            while((data = in.read()) != -1) {
                out.write(data);
            }
            in.close();
            out.close();
        } else {
            if(part.getContentType().startsWith("text/plain")) {
                System.out.println("文本内容：" + part.getContent());
            } else {
                //System.out.println("HTML内容：" + part.getContent());
            }
        }
    }  

    /**
     * @param multipart // 接卸包裹（含所有邮件内容(包裹+正文+附件)）
     * @throws Exception
     */
    private void reMultipart(Multipart multipart) throws Exception {
        //System.out.println("邮件共有" + multipart.getCount() + "部分组成");
        // 依次处理各个部分
        for (int j = 0, n = multipart.getCount(); j < n; j++) {
            //System.out.println("处理第" + j + "部分");
            Part part = multipart.getBodyPart(j);//解包, 取出 MultiPart的各个部分, 每部分可能是邮件内容,
            // 也可能是另一个小包裹(MultipPart)
            // 判断此包裹内容是不是一个小包裹, 一般这一部分是 正文 Content-Type: multipart/alternative
            if (part.getContent() instanceof Multipart) {
                Multipart p = (Multipart) part.getContent();// 转成小包裹
                //递归迭代
                reMultipart(p);
            } else {
                rePart(part);
            }
         }
    }  

    /**
     * @param args
     */
    public static void main(String[] args) {
        new POP3MailReceiverTest();
    }
}