Topic : JavaMail API (1)
Sending and Receiving Emails
Kaster Nurmukan
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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:
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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
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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
Session
Properties
Headers
Address[] To
Address[] From
String subject
Date sentDate
Message Content: String text
• This class speaks the protocol specific language to send
messages. (Usually SMTP)
• When receiving email
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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 object
Properties p = System.getProperties();
p.put("mail.smtp.host", "202.125.140.71");
// Get session
Session 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();
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0: Syed Basit <basit@ucp.edu.pk>
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>
test 1
de subject
• Send email using Gmail SMTP server
• Set Mail content type (text/plain)
• Determine the Mail Server for Any Domain:
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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
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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).
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This prevents spammers from hijacking the mail server to send
unauthorized email
JavaMail supports this username/password authorization and authentication
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To implement this, you get a transport object from the mail session and call
the connect() method with the mail host, username, and password
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See next slide for code example
HTML Email Example
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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
Session
Headers
Message Content: Multipart
MimeBodyPart
MimeBodyPart
DataHandler
String text
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
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To append an email attachment, you need to send a "multipart" message
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Create your MimeMessage object as usual, setting the from address, to
address, subject, etc...
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Create a MimeBodyPart object for your main message and set its text (or
content) to be your message
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Create a MimeBodyPart object for your attachment and call its setContent()
method to attach your file
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Create a Multipart object and add both body parts to it.
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Call your MimeMessage's setContent() method, passing in your Multipart
object
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Call Transport.send() to send the message
Whew!!!
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");
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