Reading email in Java using IMAP

We already discussed the fundamentals of Java Mail API. We discussed the way by which Java Mail API is using SMTP  to send emails with attachments and without any attachments. In the just previous post  we discussed how POP is using to read emails from Gmail inbox.In this chapter we are discussing how IMAP is using to read emails from Gmail account.

POP vs IMAP

POP is the Post Office Protocol.IMAP is the Internet Message Access Protocol.Both are protocols using to retrieve emails from email servers.If we  use POP for accessing mails from mail servers, then two way synchronization cannot be achieved.IMAP gives two way synchronization, that means  , if we read mail using IMAP then the mail  is mapped as read mail in mail server.If we  open the mail from anywhere , then the mail will be shown as read.

Reading email in Java using IMAP

Now we are looking into an example.Here we are looking how Java Mail API is using to read unread mails from mail server.Here IMAP is using as protocol.We are  accessing  recent unread mails from Gmail.So IMAP should be enabled for the corresponding email account.The procedure to enable/disable IMAP/POP is explained in  Google page.Put the following class in a dynamic web project.If we need to access mails from J2SE application , then we can download Java Mail API  from  here.Extract the zip file and include the jar files  in the project path.

import java.io.IOException;
import java.io.InputStream;
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.NoSuchProviderException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Store;
import javax.mail.Flags.Flag;
import javax.mail.search.FlagTerm;

public void readMails() {
properties = new Properties();
properties.setProperty("mail.host", "imap.gmail.com");
properties.setProperty("mail.port", "995");
properties.setProperty("mail.transport.protocol", "imaps");
session = Session.getInstance(properties,
new javax.mail.Authenticator() {
protected PasswordAuthentication getPasswordAuthentication() {
return new PasswordAuthentication(userName, password);
}
});
try {
store = session.getStore("imaps");
store.connect();
inbox = store.getFolder("INBOX");
inbox.open(Folder.READ_ONLY);
Message messages[] = inbox.search(new FlagTerm(
new Flags(Flag.SEEN), false));
;
System.out.println("Number of mails = " + messages.length);
for (int i = 0; i < messages.length; i++) { Message message = messages[i]; Address[] from = message.getFrom(); System.out.println("-------------------------------"); System.out.println("Date : " + message.getSentDate()); System.out.println("From : " + from[0]); System.out.println("Subject: " + message.getSubject()); System.out.println("Content :"); processMessageBody(message); System.out.println("--------------------------------"); } inbox.close(true); store.close(); } catch (NoSuchProviderException e) { e.printStackTrace(); } catch (MessagingException e) { e.printStackTrace(); } } public void processMessageBody(Message message) { try { Object content = message.getContent(); // check for string // then check for multipart if (content instanceof String) { System.out.println(content); } else if (content instanceof Multipart) { Multipart multiPart = (Multipart) content; procesMultiPart(multiPart); } else if (content instanceof InputStream) { InputStream inStream = (InputStream) content; int ch; while ((ch = inStream.read()) != -1) { System.out.write(ch); } } } catch (IOException e) { e.printStackTrace(); } catch (MessagingException e) { e.printStackTrace(); } } public void procesMultiPart(Multipart content) { try { int multiPartCount = content.getCount(); for (int i = 0; i < multiPartCount; i++) { BodyPart bodyPart = content.getBodyPart(i); Object o; o = bodyPart.getContent(); if (o instanceof String) { System.out.println(o); } else if (o instanceof Multipart) { procesMultiPart((Multipart) o); } } } catch (IOException e) { e.printStackTrace(); } catch (MessagingException e) { e.printStackTrace(); } } public static void main(String[] args) { ReadMailSample sample = new ReadMailSample(); sample.readMails(); } }

The search is for the unread mails from the inbox. The content of each mail will be displayed.

Output

Before  compiling and running  the class , username and password should be provided.Then compile and run the code . The unread mails will be displayed.

See Related Posts

Java  Mail API tutorial

Deleting email example

SMTP

Sending mails from Gmail account using SMTP

Sending mails with attachment from Gmail account using SMTP

POP

Reading mails from Gmail using POP