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职友集>Java面试题 > JavaMail使用POP3协议接收并解析电子邮件

JavaMail使用POP3协议接收并解析电子邮件

2015-04-07 06:30:01 阅读( 419 )

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《JavaMail使用POP3协议接收并解析电子邮件》

[java]
package cn.outofmemory.javamail;

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
* <p>Message.RecipientType.TO 收件人</p>
* <p>Message.RecipientType.CC 抄送</p>
* <p>Message.RecipientType.BCC 密送</p>
* @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 www.2cto.com
* @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);
}
}
}

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