Java Mail API

1. Java Mail API Sending and Receiving Emails

2. Mail API • Java Mail API is an easy and standard way of sending and receiving emails • Java Mail API supports following Protocols: • SMTP • POP • IMAP • MIME

3. SMTP • Simple Mail Transfer Protocol • Usually used for sending emails from clients • Also used for relaying emails from one server to another

4. SMTP

5. POP • Post office protocol • Currently Version 3 in use (Pop3 RFC1939) • Used at client side to check the emails that are received in the mailbox for a user

6. IMAP • Stands for Internet Message Access Protocol • Currently IMAP4 (RFC2060) in use • More advanced protocol for email access that allows multiple folder management on server, periodic backups and several other advanced features.

7. MIME • Multi-purpose Internet Mail Extention • Defines the contents that are to be transferred in an email

8. What do you need to use Java Mail? • You should have following two APIs • Java Mail API • JavaBeans Activation Framework(JAF) • JAF is included in JDK6

9. Mail API • As the name says, is used for sending and receiving emails. • Mail API requires JavaBeans Activation Framework

10. JAF • JavaBeans Activation Framework • Helps programmers to Determine the type of an arbitrary piece of data • Encapsulates access to it • Discovers operations that can be performed on it

11. Where to get? • Both APIs can be downloaded from http://java.sun.com • Also placed on \\shares\teachers\basit\shared docs\aip\APIs

12. How to Install? • Un-zip the javamail.zip and jaf.zip into some folder • Put mail.jar from javamail folder to the classpath • Put activation.jar from jaf folder to classpath

13. Java Mail classes • You must know following classes before you start • Session • Message • Address • Transport • Store • Folder

14. javax.mail.Session • Defines a basic mail session • Everything in mail api works due to this session

15. javax.mail.Message • Represents an email message that is either created to be sent to the recipient or is received from someone. • Message is an Abstract class • MimeMessage is the sub-class of message that understands most MIME types and is most commonly used for email handling

16. javax.mail.Address • Represents an email addres • Address is an abstract class • javax.mail.Internet.InternetAddress is the sub-class of Address

17. Message Representation

18. Transport • This class speaks the protocol specific language to send messages. (Usually SMTP)

19. Store and Folder • When receiving email • We create a session • Connect to a store with our username and password • Get specific folders (usually inbox) • And start receiving Message objects

20. Sending an Email //Create properties object Properties p = System.getProperties(); p.put("mail.smtp.host", "202.125.140.71"); // Get session Session s = Session.getDefaultInstance(p,null);

21. Sending an Email (cont) Message m = new MimeMessage(s); InternetAddress to = new InternetAddress("basit@ucp.edu.pk"); InternetAddress from = new InternetAddress("bill_gates@microsoft.com", "Bill Gates"); m.setContent("yeah this is the body", "text/plain"); m.setFrom(from); m.setRecipient(Message.RecipientType.TO, to); m.setSubject("de subject"); Transport.send(m);

22. Checking Mails Properties props = new Properties(); Session session = Session.getDefaultInstance(props, null); Store store = session.getStore("pop3"); store.connect(host, username, password); Folder folder = store.getFolder("INBOX"); folder.open(Folder.READ_ONLY);

23. Checking Mails(cont) Message message[] = folder.getMessages(); for (int i=0, n=message.length; i<n; i++) { System.out.println(i + ": " + message[i].getFrom()[0] + "\t\t" + message[i].getSubject()); } folder.close(false); store.close();

24. Output 0: Syed Basit <basit@ucp.edu.pk> test 1 1: basit@cnn.com de subject 2: basit@microsoft.com de subject 3: basit@dell.com de subject 4: basit@hell.com de subject 5: Bill Gates <bill_gates@microsoft.com> de subject

25. Let’s Try it out!!! • Send email using Gmail SMTP server • Set Mail content type (text/plain)

26. HTML Email • You can also send HTML email with JavaMail. HTML email can be used to • Use different size fonts • imbed images into your email • Use different colored text, bold, italic, etc.

27. HTML Email • With HTML email, • you set the mime message content type to "text/html" • call the setContent() method to set your html content • It helps to know a little HTML!

28. Mail Security • Virtually all mail servers require a username and password to receive email • Some mail servers require a username and password to send an email (by default, James does not). • This prevents spammers from hijacking the mail server to send unauthorized email • JavaMail supports this username/password authorization and authentication • To implement this, you get a transport object from the mail session and call the connect() method with the mail host, username, and password • See next slide for code example

29. HTML Email Example • Example of sending html message with an imbedded image using username/password authorization MimeMessage msg = new MimeMessage(mailSession); msg.setFrom(new InternetAddress("bill@msn.com")); msg.addRecipient(Message.RecipientType.TO, new InternetAddress(“tom@msn.com")); msg.setSubject(subject); String html = "<html><body><b>MY SPAM</b><br><img src='http://www.wrfportal.org/images/NOAA_logo.jpg'> </body></html>"; msg.setContent(html, "text/html"); Transport transport = mailSession.getTransport("smtp"); transport.connect("localhost","user", "passwd"); msg.saveChanges(); transport.sendMessage(msg, msg.getAllRecipients()); transport.close();

30. MultiPart Representation

31. javax.Activation.DataSource • Interface that allows access to file type and to streams that can manipulate the file • public String getContentType() returns the name of the MIME file type • Implemented by javax.Activation.FileDataSource • Used by JavaMail to create and retrieve e-mail attachments • Constructors • FileDataSource(File file) • FileDataSource(String filename)

32. javax.Activation.DataHandler • Wrapper for DataSource objects so that the user does not need to manipulate the bytes for each file • Constructors • DataHandler(DataSource ds) • DataHandler(Object obj, String mimeType) • Public Object getContent() Returns the data as the object that represents its content type (ie runing this method on a text message returns a String)

33. javax.mail.Part Revisited • Allows manipulation of DataHandlers • public void setDataHandler(DataHandler dh) • public DataHandler getDataHandler() • Other methods abstract user away from need to directly manipulate DataHandler • public void setContent(Object object, String contentType) • public Object getContent()

34. javax.mail.MimeBodyPart • Implements the Part interface (indirectly through a few abstract classes) • Contains the content for a single part of an e-mail message • Uses several methods to manipulate content directly or through DataHandler or streams • Key Methods • public void setText(String text): for text/plain content, makes a String into the message content • public void setDataHandler(DataHandler dh) sets the content using a DataHandler (which may be text or any other permitted content) • public void setFileName(String filename) sets the filename associated with the content, if the content represents a file

35. Javax.mail.Multipart • Container that holds multiple parts • Each part is indexed, starting with 0 • A Multipart object may be a part within another Multipart object • Key Methods • public void addBodyPart(BodyPart part) • public void addBodyPart(BodyPart part, int index) • public int getCount() returns the number of BodyPart objects

36. Email attachments -1 • To append an email attachment, you need to send a "multipart" message • Create your MimeMessage object as usual, setting the from address, to address, subject, etc... • Create a MimeBodyPart object for your main message and set its text (or content) to be your message • Create a MimeBodyPart object for your attachment and call its setContent() method to attach your file • Create a Multipart object and add both body parts to it. • Call your MimeMessage's setContent() method, passing in your Multipart object • Call Transport.send() to send the message • Whew!!!

37. Email attachment Example-1 MimeMessage msg = new MimeMessage(getMailSession()); msg.setFrom(new InternetAddress("bill.gates@msn.com")); msg.addRecipient(Message.RecipientType.TO, new InternetAddress("larry.ellison@oracle.com")); msg.setSubject("RE: Oracle vs SQL Server"); //Create the main message (body) part for text MimeBodyPart mainBodyPart = new MimeBodyPart(); mainBodyPart.setText("Here is my message");

38. Email attachment Example-2 //Create attachment body part MimeBodyPart attachBodyPart = new MimeBodyPart(); DataSource source = new FileDataSource("1.jpg"); attachBodyPart.setDataHandler(new DataHandler(source)); attachBodyPart.setFileName("1.jpg"); //Now create the multipart and add the parts Multipart multipart = new MimeMultipart(); multipart.addBodyPart(mainBodyPart); multipart.addBodyPart(attachBodyPart); //add the multipart to the original Mime message msg.setContent(multipart); Transport.send(msg);