Java Mail API

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Java Mail API

• Sending and Receiving Emails

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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

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SMTP

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

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SMTP
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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

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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.

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MIME

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

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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

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Mail API

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

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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

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Where to get?

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

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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

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Java Mail classes

• You must know following classes before you start
• Session
• Message
• Address
• Transport
• Store
• Folder

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javax.mail.Session

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

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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

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javax.mail.Address

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

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Message Representation
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Transport

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

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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

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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)

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Sending an Email (cont)

• Message m new MimeMessage(s)
• InternetAddress to new InternetAddress("basit_at_uc
  p.edu.pk")
• InternetAddress from new InternetAddress("bill_g
  ates_at_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)

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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)

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Checking Mails(cont)

• Message message folder.getMessages()
• for (int i0, nmessage.length iltn i)
• System.out.println(i " "
  messagei.getFrom()0 "\t\t"
  messagei.getSubject())
• folder.close(false)
• store.close()

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Output

• 0 Syed Basit ltbasit_at_ucp.edu.pkgt test 1
• 1 basit_at_cnn.com de subject
• 2 basit_at_microsoft.com de subject
• 3 basit_at_dell.com de subject
• 4 basit_at_hell.com de subject
• 5 Bill Gates ltbill_gates_at_microsoft.comgt de
  subject

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Lets Try it out!!!

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

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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.

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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!

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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

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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_at_msn.com"))
• msg.addRecipient(Message.RecipientType.TO, new
• InternetAddress(tom_at_msn.com"))
• msg.setSubject(subject)
• String html "lthtmlgtltbodygtltbgtMY SPAMlt/bgtltbrgtltimg
• src'http//www.wrfportal.org/images/NOAA_logo.
  jpg'gt
• lt/bodygtlt/htmlgt"
• msg.setContent(html, "text/html")
• Transport transport mailSession.getTransport("sm
  tp")
• transport.connect("localhost","user", "passwd")
• msg.saveChanges()
• transport.sendMessage(msg, msg.getAllRecipients())
  
• transport.close()

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MultiPart Representation
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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)

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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)

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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()

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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

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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

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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!!!

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Email attachment Example-1
MimeMessage msg new MimeMessage(getMailSession()
) msg.setFrom(new InternetAddress("bill.gates_at_msn
.com")) msg.addRecipient(Message.RecipientType.TO
, new InternetAddress("larry.ellison_at_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")
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Email attachment Example-2
//Create attachment body part MimeBodyPart
attachBodyPart new MimeBodyPart() DataSource
source new FileDataSource("1.jpg") attachBodyPa
rt.setDataHandler(new DataHandler(source)) attach
BodyPart.setFileName("1.jpg") //Now create the
multipart and add the parts Multipart multipart
new MimeMultipart() multipart.addBodyPart(mainBod
yPart) multipart.addBodyPart(attachBodyPart) /
/add the multipart to the original Mime
message msg.setContent(multipart) Transport.send
(msg)