通过JavaMail下载邮件附件
通过JavaMail下载邮件附件
- 需求
- JavaMail
- 工具类
- 附件类
- 使用
- 遇到的一些意外
需求
因为某些特定的业务需要，要从邮件中获取附件。花了一些时间，最终业务需求实现了，但是也遇到一些坑，所以记录一下。
JavaMail
使用JavaMail来实现邮件的一系列操作（发送、接收），我使用的版本是1.6.2（maven仓库里有），不多说，上代码
工具类
package com.xxx.xxx;
import com.sun.mail.imap.IMAPFolder;
import com.sun.mail.imap.IMAPStore;
import com.sun.mail.pop3.POP3Folder;
import com.sun.mail.pop3.POP3Store;
import org.castor.util.Base64Decoder;
import javax.activation.DataHandler;
import javax.activation.FileDataSource;
import javax.mail.*;
import javax.mail.internet.*;
import javax.mail.search.*;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.security.Security;
import java.util.Date;
import java.util.List;
import java.util.Properties;
/**
* @author jiangyw
* @date 2019/1/7 19:29
*
* 处理邮件工具类
* 接收/发送服务器根据不同邮箱有不同的地址
* 在邮箱设置里都可找到
*/
public class MailUtil {
// 发送服务器
private static final String SEND_SMTP_HOST = "smtp.exmail.qq.com";
private static final int SEND_SMTP_PORT = 465;
// 接收服务器
private static final String RECEIVE_IMAP_HOST = "imap.exmail.qq.com";
private static final int RECEIVE_IMAP_PORT = 993;
private static final String RECEIVE_POP_HOST = "pop.exmail.qq.com";
private static final int RECEIVE_POP_PORT = 110;
// 账号
private String user;
// 密码
private String password;
private IMAPFolder imapFolder = null;
private IMAPStore imapStore = null;
private POP3Store pop3Store = null;
private POP3Folder pop3Folder = null;
public MailUtil() {
this("your email address", "your email password");
}
private MailUtil(String user, String password) {
this.user = user;
this.password = password;
}
/**
* 发送邮件
*
* @param toEmail 收件人邮箱地址
* @param subject 邮件标题
* @param content 邮件内容 可以是html内容
*/
public void send(String toEmail, String subject, String content) {
Session session = loadSendSession();
// session.setDebug(true);
// 创建邮件消息
MimeMessage message = new MimeMessage(session);
try {
// 设置发件人
message.setFrom(new InternetAddress(user));
Address[] a = new Address[1];
a[0] = new InternetAddress(user);
message.setReplyTo(a);
// 设置收件人
InternetAddress to = new InternetAddress(toEmail);
message.setRecipient(MimeMessage.RecipientType.TO, to);
// 设置邮件标题
message.setSubject(subject);
// 设置邮件的内容体
message.setContent(content, "text/html;charset=UTF-8");
// 发送邮件
Transport.send(message);
} catch (MessagingException e) {
e.printStackTrace();
String err = e.getMessage();
// 在这里处理message内容， 格式是固定的
System.out.println(err);
}
}
/**
* 发送邮件 带附件
*
* @param toEmail 收件人邮箱地址
* @param subject 邮件标题
* @param content 邮件内容 可以是html内容
* @param attachPath 附件路径
*/
public void send(String toEmail, String subject, String content, String attachPath) {
Session session = loadSendSession();
MimeMessage mm = new MimeMessage(session);
try {
//发件人
mm.setFrom(new InternetAddress(user));
//收件人
mm.setRecipient(Message.RecipientType.TO, new InternetAddress(toEmail)); // 设置收件人
// mm.setRecipient(Message.RecipientType.CC, new
// InternetAddress("[email protected]")); //设置抄送人
//标题
mm.setSubject(subject);
//内容
Multipart multipart = new MimeMultipart();
//body部分
BodyPart contentPart = new MimeBodyPart();
contentPart.setContent(content, "text/html;charset=utf-8");
multipart.addBodyPart(contentPart);
//附件部分
BodyPart attachPart = new MimeBodyPart();
FileDataSource fileDataSource = new FileDataSource(attachPath);
attachPart.setDataHandler(new DataHandler(fileDataSource));
attachPart.setFileName(MimeUtility.encodeText(fileDataSource.getName()));
multipart.addBodyPart(attachPart);
mm.setContent(multipart);
Transport.send(mm);
} catch (Exception e) {
e.printStackTrace();
String err = e.getMessage();
// 在这里处理message内容， 格式是固定的
System.out.println(err);
}
}
private Session loadSendSession() {
try {
// 配置发送邮件的环境属性
final Properties props = new Properties();
// 表示SMTP发送邮件，需要进行身份验证
props.put("mail.smtp.auth", "true");
props.put("mail.smtp.host", SEND_SMTP_HOST);
// props.put("mail.smtp.port", SEND_SMTP_PORT);
// 如果使用ssl，则去掉使用25端口的配置，进行如下配置,
props.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
props.put("mail.smtp.socketFactory.port", SEND_SMTP_PORT);
props.put("mail.smtp.port", SEND_SMTP_PORT);
// 发件人的账号
props.put("mail.user", user);
// 访问SMTP服务时需要提供的密码
props.put("mail.password", password);
// 构建授权信息，用于进行SMTP进行身份验证
Authenticator authenticator = new Authenticator() {
@Override
protected PasswordAuthentication getPasswordAuthentication() {
// 用户名、密码
String userName = props.getProperty("mail.user");
String password = props.getProperty("mail.password");
return new PasswordAuthentication(userName, password);
}
};
// 使用环境属性和授权信息，创建邮件会话
return Session.getInstance(props, authenticator);
} catch (Exception e) {
e.printStackTrace();
System.out.println("mail session is null");
}
return null;
}
public void saveFile(List list) throws IOException {
for (MailAttachment mailAttachment : list) {
InputStream inputStream = mailAttachment.getInputStream();
FileOutputStream outputStream = new FileOutputStream(new File("C:\\Users\\jiangyw\\Desktop\\test.pdf"));
int len;
byte[] bytes = new byte[1024];
while ((len = inputStream.read(bytes)) != -1) {
outputStream.write(bytes, 0, len);
outputStream.flush();
}
inputStream.close();
outputStream.close();
}
}
/**
* 获取附件
* 只获取附件里的
* 邮件内容里的附件（图片等）忽略
* @param part 邮件中多个组合体中的其中一个组合体
* @param list 附件容器
* @throws UnsupportedEncodingException
* @throws MessagingException
* @throws FileNotFoundException
* @throws IOException
*/
public void getAttachment(Part part, List list) 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 disposition = bodyPart.getDisposition();
if (disposition != null && (disposition.equalsIgnoreCase(Part.ATTACHMENT) || disposition.equalsIgnoreCase(Part.INLINE))) {
InputStream is = bodyPart.getInputStream();
// 附件名通过MimeUtility解码，否则是乱码
String name = MimeUtility.decodeText(bodyPart.getFileName());
list.add(new MailAttachment(name, is));
} else if (bodyPart.isMimeType("multipart/*")) {
getAttachment(bodyPart, list);
} else {
String contentType = bodyPart.getContentType();
if (contentType.contains("name") || contentType.contains("application")) {
}
}
}
} else if (part.isMimeType("message/rfc822")) {
getAttachment((Part) part.getContent(), list);
}
}
/**
* 判断邮件中是否包含附件
*
* @return 邮件中是否存在附件
* @throws MessagingException
* @throws IOException
*/
public boolean hasAttachment(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 = hasAttachment(bodyPart);
} else {
String contentType = bodyPart.getContentType();
if (contentType.contains("application")) {
flag = true;
}
if (contentType.contains("name")) {
flag = true;
}
}
if (flag) break;
}
} else if (part.isMimeType("message/rfc822")) {
flag = hasAttachment((Part) part.getContent());
}
return flag;
}
/**
* 获得邮件文本内容
*
* @param part 邮件体
* @param textContent 存储邮件文本内容的字符串
* @param htmlContent 存储邮件html内容的字符串
* @throws MessagingException
* @throws IOException
*/
public void getMailTextContent(Part part, StringBuffer textContent, StringBuffer htmlContent) 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) {
String contentType = part.getContentType();
if (contentType.startsWith("TEXT/PLAIN") || contentType.startsWith("text/plain")) {
textContent.append(part.getContent().toString());
}
if (contentType.startsWith("TEXT/HTML") || contentType.startsWith("text/html")) {
htmlContent.append(part.getContent().toString());
}
} else if (part.isMimeType("message/rfc822")) {
getMailTextContent((Part) part.getContent(), textContent, htmlContent);
} 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, textContent, htmlContent);
}
}
}
public String getSubject(Message message) throws MessagingException {
return message.getSubject();
}
/**
* 获取邮件信息
* IMAP协议
* 下载附件的时候巨慢
* 如果需要获取附件的时候不推荐使用
* 该协议下只能查询receivedDate
* sentDate都为null
*
* @throws MessagingException
*/
public Message[] getImapMessages() throws MessagingException {
String SSL_FACTORY = "javax.net.ssl.SSLSocketFactory";
Security.addProvider(new com.sun.net.ssl.internal.ssl.Provider());
System.setProperty("mail.mime.splitlongparameters", "false");
Properties props = System.getProperties();
props.setProperty("mail.imap.socketFactory.class", SSL_FACTORY);
props.setProperty("mail.imap.socketFactory.port", "993");
props.setProperty("mail.imapStore.protocol", "imap");
props.setProperty("mail.imap.host", RECEIVE_IMAP_HOST);
props.setProperty("mail.imap.port", "993");
props.setProperty("mail.imap.auth.login.disable", "true");
Session session = Session.getDefaultInstance(props, null);
session.setDebug(false);
imapStore = (IMAPStore) session.getStore("imap"); // 使用imap会话机制，连接服务器
imapStore.connect(RECEIVE_IMAP_HOST, RECEIVE_IMAP_PORT, user, password);
imapFolder = (IMAPFolder) imapStore.getFolder("INBOX"); //收件箱
imapFolder.open(Folder.READ_WRITE);
// 获取前一天的邮件信息
SearchTerm endTerm = new ReceivedDateTerm(ComparisonTerm.LE, new Date(System.currentTimeMillis() + 24 * 60 * 60 * 1000L));
SearchTerm startTerm = new ReceivedDateTerm(ComparisonTerm.GE, new Date(System.currentTimeMillis() - 24 * 60 * 60 * 1000L));
SearchTerm searchTerm = new AndTerm(startTerm, endTerm);
return imapFolder.search(searchTerm);
}
/**
* 通过pop3协议获取邮件信息
* pop3协议下只能通过sentDate来查询
* receivedDate都为null
*
* @return Message[]
* @throws MessagingException
*/
public Message[] getPopMessages() throws MessagingException {
Properties props = new Properties();
props.setProperty("mail.imapStore.protocol", "pop3"); // 使用pop3协议
props.setProperty("mail.pop3.port", "110"); // 端口
props.setProperty("mail.pop3.host", RECEIVE_POP_HOST); // pop3服务器
Session session = Session.getInstance(props);
pop3Store = (POP3Store) session.getStore("pop3");
pop3Store.connect(RECEIVE_POP_HOST, RECEIVE_POP_PORT, user, password);
// 获得收件箱
pop3Folder = (POP3Folder) pop3Store.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）
*/
pop3Folder.open(Folder.READ_ONLY); //打开收件箱
// 获取前一天的邮件信息
SearchTerm endTerm = new SentDateTerm(ComparisonTerm.LE, new Date(System.currentTimeMillis() + 24 * 60 * 60 * 1000L));
SearchTerm startTerm = new SentDateTerm(ComparisonTerm.GE, new Date(System.currentTimeMillis() - 24 * 60 * 60 * 1000L));
SearchTerm searchTerm = new AndTerm(startTerm, endTerm);
// 得到收件箱中的所有邮件,并解析
return pop3Folder.search(searchTerm);
}
/**
* 关闭folder和store资源
*
* @throws MessagingException
*/
public void close() throws MessagingException {
if (imapFolder != null) {
imapFolder.close(false);
}
if (imapStore != null) {
imapStore.close();
}
if (pop3Folder != null) {
pop3Folder.close(false);
}
if (pop3Store != null) {
pop3Store.close();
}
}
}
附件类
很简单的容器类：
package com.xxx.xxx;
import java.io.InputStream;
/**
* @author jiangyw
* @date 2019/1/10 21:14
*
* 邮件附件类
*/
public class MailAttachment {
private String name;
private InputStream inputStream;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public InputStream getInputStream() {
return inputStream;
}
public void setInputStream(InputStream inputStream) {
this.inputStream = inputStream;
}
public MailAttachment(String name, InputStream inputStream) {
this.name = name;
this.inputStream = inputStream;
}
}
使用
public void readMail() throws MessagingException {
long startTime = System.currentTimeMillis();
MailUtil mailUtil = new MailUtil();
Message[] messages = mailUtil.getPopMessages();
for (Message message : messages) {
String subject = mailUtil.getSubject(message);
try {
List mailAttachments = new ArrayList<>();
mailUtil.getAttachment(message, mailAttachments);
saveAttachment(mailAttachments);
}
} catch (Exception ignore) {
}
}
mailUtil.close();
System.out.println("解析邮件共耗时：" + (System.currentTimeMillis() - startTime) + "毫秒");
}
private void saveAttachment(List list) throws IOException {
for (MailAttachment mailAttachment : list) {
InputStream inputStream = mailAttachment.getInputStream();
FileOutputStream outputStream = new FileOutputStream(new File( "your path");
int len;
byte[] bytes = new byte[1024 * 1024];
while ((len = inputStream.read(bytes)) != -1) {
outputStream.write(bytes, 0, len);
outputStream.flush();
}
inputStream.close();
outputStream.close();
}
}
遇到的一些意外
- 下载附件速度慢到令人发指！！！（看图）
两个一共不到4M的附件，下载总共用了1000多秒！！！
解决方法：不要用IMAP协议接收邮件信息，用POP3协议，换了协议之后的速度（看图）
速度差了两个数量级！！！ - 在代码里也注释了，用IMAP协议时没有SentDate，用POP3协议时没有ReceivedDate；这两个协议具体的区别百度一下你就知道，我是因为要获取前一天的邮件，所以是根据日期来搜索。
- 附件名乱码，这个其实很简单，用JavaMail自带的MimeUtility解码一下就好。