Topic : JavaMail API (1)Sending and Receiving Emails

Kaster Nurmukan

• Overview of JavaMail API• SMTP • POP• MIME• javaMail API• HTML Email• Email With attachment

• Java Mail API is an easy and standard way of sending and receiving emails

• Java Mail API supports following Protocols:– SMTP– POP– IMAP– MIME

• Simple Mail Transfer Protocol– Usually used for sending emails from clients

– Also used for relaying emails from one server to another

• 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

• 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.

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

• You should have following two APIs– Java Mail API

– JavaBeans Activation Framework(JAF)

– JAF is included in JDK6

• As the name says, is used for sending and receiving emails.

• Mail API requires JavaBeans Activation Framework

• 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

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

APIs

• 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

• You must know following classes before you start– Session

– Message

– Address

– Transport

– Store

– Folder

• Defines a basic mail session• Everything in mail api works due to this session

• 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

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

Address

MimeMessage

Headers

Session

Address[] To Address[] From

String subject Date sentDate

Message Content: String text

Properties

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

• 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

//Create properties objectProperties p = System.getProperties();p.put("mail.smtp.host", "202.125.140.71");

// Get sessionSession s = Session.getDefaultInstance(p,null);

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);

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);

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();

0: Syed Basit <basit@ucp.edu.pk> test 11: basit@cnn.com de subject 2: basit@microsoft.com de subject3: basit@dell.com de subject 4: basit@hell.com de subject 5: Bill Gates <bill_gates@microsoft.com> de subject

• Send email using Gmail SMTP server• Set Mail content type (text/plain)

• Determine the Mail Server for Any Domain:– Click Start.– CMD– Type nslookup– Type set type = mx – type the name of the domain. Example: google.com

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.

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!

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

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();

MimeMessage Headers Session

Message Content: Multipart MimeBodyPart MimeBodyPart

String text

DataHandler

FileDataSource

File

String fileName

• 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)

• 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)

• 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()

• 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

• 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

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!!!

Email attachment Example-1MimeMessage 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");

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);

• http://www.oracle.com