message
mainMultipart (content for message, subType="mixed")
->htmlAndTextBodyPart (bodyPart1 for mainMultipart)
->htmlAndTextMultipart (content for htmlAndTextBodyPart, subType="alternative")
->textBodyPart (bodyPart2 for the htmlAndTextMultipart)
->text (content for textBodyPart)
->htmlBodyPart (bodyPart1 for htmlAndTextMultipart)
->html (content for htmlBodyPart)
->fileBodyPart1 (bodyPart2 for the mainMultipart)
->FileDataHandler (content for fileBodyPart1 )
以及构建这样一个信息的代码:
// the parent or main part if you will
Multipart mainMultipart = new MimeMultipart("mixed");
// this will hold text and html and tells the client there are 2 versions of the message (html and text). presumably text
// being the alternative to html
Multipart htmlAndTextMultipart = new MimeMultipart("alternative");
// set text
MimeBodyPart textBodyPart = new MimeBodyPart();
textBodyPart.setText(text);
htmlAndTextMultipart.addBodyPart(textBodyPart);
// set html (set this last per rfc1341 which states last = best)
MimeBodyPart htmlBodyPart = new MimeBodyPart();
htmlBodyPart.setContent(html, "text/html; charset=utf-8");
htmlAndTextMultipart.addBodyPart(htmlBodyPart);
// stuff the multipart into a bodypart and add the bodyPart to the mainMultipart
MimeBodyPart htmlAndTextBodyPart = new MimeBodyPart();
htmlAndTextBodyPart.setContent(htmlAndTextMultipart);
mainMultipart.addBodyPart(htmlAndTextBodyPart);
// attach file body parts directly to the mainMultipart
MimeBodyPart filePart = new MimeBodyPart();
FileDataSource fds = new FileDataSource("/path/to/some/file.txt");
filePart.setDataHandler(new DataHandler(fds));
filePart.setFileName(fds.getName());
mainMultipart.addBodyPart(filePart);
// set message content
message.setContent(mainMultipart);
import javax.activation.DataHandler;
import javax.activation.DataSource;
import javax.activation.URLDataSource;
import javax.mail.BodyPart;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMultipart;
import java.net.URL;
import java.util.HashMap;
import java.util.List;
import java.util.UUID;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* Created by StrongMan on 25/05/14.
*/
public class MailContentBuilder {
private static final Pattern COMPILED_PATTERN_SRC_URL_SINGLE = Pattern.compile("src='([^']*)'", Pattern.CASE_INSENSITIVE);
private static final Pattern COMPILED_PATTERN_SRC_URL_DOUBLE = Pattern.compile("src=\"([^\"]*)\"", Pattern.CASE_INSENSITIVE);
/**
* Build an email message.
*
* The HTML may reference the embedded image (messageHtmlInline) using the filename. Any path portion is ignored to make my life easier
* e.g. If you pass in the image C:\Temp\dog.jpg you can use <img src="dog.jpg"/> or <img src="C:\Temp\dog.jpg"/> and both will work
*
* @param messageText
* @param messageHtml
* @param messageHtmlInline
* @param attachments
* @return
* @throws MessagingException
*/
public Multipart build(String messageText, String messageHtml, List<URL> messageHtmlInline, List<URL> attachments) throws MessagingException {
final Multipart mpMixed = new MimeMultipart("mixed");
{
// alternative
final Multipart mpMixedAlternative = newChild(mpMixed, "alternative");
{
// Note: MUST RENDER HTML LAST otherwise iPad mail client only renders the last image and no email
addTextVersion(mpMixedAlternative,messageText);
addHtmlVersion(mpMixedAlternative,messageHtml, messageHtmlInline);
}
// attachments
addAttachments(mpMixed,attachments);
}
//msg.setText(message, "utf-8");
//msg.setContent(message,"text/html; charset=utf-8");
return mpMixed;
}
private Multipart newChild(Multipart parent, String alternative) throws MessagingException {
MimeMultipart child = new MimeMultipart(alternative);
final MimeBodyPart mbp = new MimeBodyPart();
parent.addBodyPart(mbp);
mbp.setContent(child);
return child;
}
private void addTextVersion(Multipart mpRelatedAlternative, String messageText) throws MessagingException {
final MimeBodyPart textPart = new MimeBodyPart();
textPart.setContent(messageText, "text/plain");
mpRelatedAlternative.addBodyPart(textPart);
}
private void addHtmlVersion(Multipart parent, String messageHtml, List<URL> embeded) throws MessagingException {
// HTML version
final Multipart mpRelated = newChild(parent,"related");
// Html
final MimeBodyPart htmlPart = new MimeBodyPart();
HashMap<String,String> cids = new HashMap<String, String>();
htmlPart.setContent(replaceUrlWithCids(messageHtml,cids), "text/html");
mpRelated.addBodyPart(htmlPart);
// Inline images
addImagesInline(mpRelated, embeded, cids);
}
private void addImagesInline(Multipart parent, List<URL> embeded, HashMap<String,String> cids) throws MessagingException {
if (embeded != null)
{
for (URL img : embeded)
{
final MimeBodyPart htmlPartImg = new MimeBodyPart();
DataSource htmlPartImgDs = new URLDataSource(img);
htmlPartImg.setDataHandler(new DataHandler(htmlPartImgDs));
String fileName = img.getFile();
fileName = getFileName(fileName);
String newFileName = cids.get(fileName);
boolean imageNotReferencedInHtml = newFileName == null;
if (imageNotReferencedInHtml) continue;
// Gmail requires the cid have <> around it
htmlPartImg.setHeader("Content-ID", "<"+newFileName+">");
htmlPartImg.setDisposition(BodyPart.INLINE);
parent.addBodyPart(htmlPartImg);
}
}
}
private void addAttachments(Multipart parent, List<URL> attachments) throws MessagingException {
if (attachments != null)
{
for (URL attachment : attachments)
{
final MimeBodyPart mbpAttachment = new MimeBodyPart();
DataSource htmlPartImgDs = new URLDataSource(attachment);
mbpAttachment.setDataHandler(new DataHandler(htmlPartImgDs));
String fileName = attachment.getFile();
fileName = getFileName(fileName);
mbpAttachment.setDisposition(BodyPart.ATTACHMENT);
mbpAttachment.setFileName(fileName);
parent.addBodyPart(mbpAttachment);
}
}
}
public String replaceUrlWithCids(String html, HashMap<String,String> cids)
{
html = replaceUrlWithCids(html, COMPILED_PATTERN_SRC_URL_SINGLE, "src='cid:@cid'", cids);
html = replaceUrlWithCids(html, COMPILED_PATTERN_SRC_URL_DOUBLE, "src=\"cid:@cid\"", cids);
return html;
}
private String replaceUrlWithCids(String html, Pattern pattern, String replacement, HashMap<String,String> cids) {
Matcher matcherCssUrl = pattern.matcher(html);
StringBuffer sb = new StringBuffer();
while (matcherCssUrl.find())
{
String fileName = matcherCssUrl.group(1);
// Disregarding file path, so don't clash your filenames!
fileName = getFileName(fileName);
// A cid must start with @ and be globally unique
String cid = "@" + UUID.randomUUID().toString() + "_" + fileName;
if (cids.containsKey(fileName))
cid = cids.get(fileName);
else
cids.put(fileName,cid);
matcherCssUrl.appendReplacement(sb,replacement.replace("@cid",cid));
}
matcherCssUrl.appendTail(sb);
html = sb.toString();
return html;
}
private String getFileName(String fileName) {
if (fileName.contains("/"))
fileName = fileName.substring(fileName.lastIndexOf("/")+1);
return fileName;
}
}
以及在 Gmail 中使用它的一个例子
/**
* Created by StrongMan on 25/05/14.
*/
import com.sun.mail.smtp.SMTPTransport;
import java.net.URL;
import java.security.Security;
import java.util.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.activation.DataHandler;
import javax.activation.DataSource;
import javax.activation.URLDataSource;
import javax.mail.*;
import javax.mail.internet.*;
/**
*
* http://stackoverflow.com/questions/14744197/best-practices-sending-javamail-mime-multipart-emails-and-gmail
* http://stackoverflow.com/questions/3902455/smtp-multipart-alternative-vs-multipart-mixed
*
*
*
* @author doraemon
*/
public class GoogleMail {
private GoogleMail() {
}
/**
* Send email using GMail SMTP server.
*
* @param username GMail username
* @param password GMail password
* @param recipientEmail TO recipient
* @param title title of the message
* @param messageText message to be sent
* @throws AddressException if the email address parse failed
* @throws MessagingException if the connection is dead or not in the connected state or if the message is not a MimeMessage
*/
public static void Send(final String username, final String password, String recipientEmail, String title, String messageText, String messageHtml, List<URL> messageHtmlInline, List<URL> attachments) throws AddressException, MessagingException {
GoogleMail.Send(username, password, recipientEmail, "", title, messageText, messageHtml, messageHtmlInline,attachments);
}
/**
* Send email using GMail SMTP server.
*
* @param username GMail username
* @param password GMail password
* @param recipientEmail TO recipient
* @param ccEmail CC recipient. Can be empty if there is no CC recipient
* @param title title of the message
* @param messageText message to be sent
* @throws AddressException if the email address parse failed
* @throws MessagingException if the connection is dead or not in the connected state or if the message is not a MimeMessage
*/
public static void Send(final String username, final String password, String recipientEmail, String ccEmail, String title, String messageText, String messageHtml, List<URL> messageHtmlInline, List<URL> attachments) throws AddressException, MessagingException {
Security.addProvider(new com.sun.net.ssl.internal.ssl.Provider());
final String SSL_FACTORY = "javax.net.ssl.SSLSocketFactory";
// Get a Properties object
Properties props = System.getProperties();
props.setProperty("mail.smtps.host", "smtp.gmail.com");
props.setProperty("mail.smtp.socketFactory.class", SSL_FACTORY);
props.setProperty("mail.smtp.socketFactory.fallback", "false");
props.setProperty("mail.smtp.port", "465");
props.setProperty("mail.smtp.socketFactory.port", "465");
props.setProperty("mail.smtps.auth", "true");
/*
If set to false, the QUIT command is sent and the connection is immediately closed. If set
to true (the default), causes the transport to wait for the response to the QUIT command.
ref : http://java.sun.com/products/javamail/javadocs/com/sun/mail/smtp/package-summary.html
http://forum.java.sun.com/thread.jspa?threadID=5205249
smtpsend.java - demo program from javamail
*/
props.put("mail.smtps.quitwait", "false");
Session session = Session.getInstance(props, null);
// -- Create a new message --
final MimeMessage msg = new MimeMessage(session);
// -- Set the FROM and TO fields --
msg.setFrom(new InternetAddress(username + "@gmail.com"));
msg.setRecipients(Message.RecipientType.TO, InternetAddress.parse(recipientEmail, false));
if (ccEmail.length() > 0) {
msg.setRecipients(Message.RecipientType.CC, InternetAddress.parse(ccEmail, false));
}
msg.setSubject(title);
// mixed
MailContentBuilder mailContentBuilder = new MailContentBuilder();
final Multipart mpMixed = mailContentBuilder.build(messageText, messageHtml, messageHtmlInline, attachments);
msg.setContent(mpMixed);
msg.setSentDate(new Date());
SMTPTransport t = (SMTPTransport)session.getTransport("smtps");
t.connect("smtp.gmail.com", username, password);
t.sendMessage(msg, msg.getAllRecipients());
t.close();
}
}
public Multipart build(String messageText, String messageHtml, List<URL> messageHtmlInline) throws MessagingException {
final Multipart mpAlternative = new MimeMultipart("alternative");
{
// Note: MUST RENDER HTML LAST otherwise iPad mail client only renders
// the last image and no email
addTextVersion(mpAlternative,messageText);
addHtmlVersion(mpAlternative,messageHtml, messageHtmlInline);
}
return mpAlternative;
}
In addTextVersion method I added charset when adding content this probably could/should be passed in, but I just added it statically.
textPart.setContent(messageText, "text/plain");
to
textPart.setContent(messageText, "text/plain; charset=UTF-8");
The last item was adding to the addImagesInline method. I added setting the image filename to the header by the following code. If you don't do this then at least on Android default mail client it will have inline images that have a name of Unknown and will not automatically download them and present in email.
for (URL img : embeded) {
final MimeBodyPart htmlPartImg = new MimeBodyPart();
DataSource htmlPartImgDs = new URLDataSource(img);
htmlPartImg.setDataHandler(new DataHandler(htmlPartImgDs));
String fileName = img.getFile();
fileName = getFileName(fileName);
String newFileName = cids.get(fileName);
boolean imageNotReferencedInHtml = newFileName == null;
if (imageNotReferencedInHtml) continue;
htmlPartImg.setHeader("Content-ID", "<"+newFileName+">");
htmlPartImg.setDisposition(BodyPart.INLINE);
**htmlPartImg.setFileName(newFileName);**
parent.addBodyPart(htmlPartImg);
}
So finally, this is the list of clients I tested on.
Outlook 2010,
Outlook Web App,
Internet Explorer 11,
Firefox,
Chrome,
Outlook using Apple’s native app,
Email going through Gmail -
Browser mail client,
Internet Explorer 11,
Firefox,
Chrome,
Android default mail client,
osx IPhone default mail client,
Gmail mail client on Android,
Gmail mail client on IPhone,
Email going through Yahoo -
Browser mail client,
Internet Explorer 11,
Firefox,
Chrome,
Android default mail client,
osx IPhone default mail client.
