Java mail (lập TRÌNH WEB SLIDE)

Server-side
Web Programming
Lecture 19:
Java Mail


How email works
Sending Client

Receiving Client

Mail Client
Software

Mail Client
Software

SMTP

POP/ IMAP

Receiving Server

Sending Server
Mail Server
Software

SMTP

Mail Server
Software

3 protocols
• SMTP: Simple Mail Transfer Protocol
– is used to send a message from the mail client
software to your mail server / or from one mail server
to another

• POP: Post Office Protocol
– transfers all messages from the mail server to the
mail client. POP in version 3: POP3

• IMAP: Internet Message Access Protocol
– Is used by web-based mail services such as Hotmail,
Yahoo, and Gmail.
– Allows a web browser to read messages that are
stored on the mail server. IMAP in version 4: IMAP4


Normal Email Process
•

Mail client software converts message to SMTP (or other) format
before sending to server
• Common form for usual components of message:
–
–
–
–
–

•

Sender
Recipient(s)
Subject
Text
Etc.

Mail server sends message in MIME protocol to receiving server
– Multipurpose Internet Message Extension

•

Mail client software on receiving client accesses using mail client
software (possibly different)
– POP
– IMAP


Java Mail
•

Java Mail API is a programming interface that makes it easy for
Java developers to write code that automatically sends an email.
• Key idea: Java Mail (or other mail software) must emulate what mail
client software does
– Create SMTP or other protocol message
– Insert required mail components
– Connect with sending server and transmit message

•

Requires mail classes
– Download from www.java.sun.com
– Insert mail.jar and activation.jar file into java libraries
• mail. jar: contains the Java classes for the Java Mail API
• activation. jar: contains the Java classes for the JavaBean Activation
Framework. These classes are necessary for the JavaMail API to run


How to install the Java Mail API and
JavaBeans Activation Framework API
• Locate the download page for the JavaMail
API/JavaBeans Activation Framework API on the
Java website: www.java.sun.com
• Click on the Download button and follow the
instructions
• Save the zip file: javamail-1_4.zip/jaf-1_1.zip to
your hard disk
• Extract the files from the zip file
• Copy the mail.jar/activation.jar file to the JDK’s
jre\lib\ext directory


Steps in Java Mail
•

Create a mail session
– Creates email message object

•

Set message components
– Properties of message object

•

Set addresses
– Can be list for group of recipients

•

Send message
– May need to identify self to server

•

Will need mail libraries

<%@ page import="javax.mail.*, javax.mail.internet.*, java.util.*"%>


Creating an Email Session
•

Create a Properties object to store information:
– Generic Java class to store attribute/value pairs
– Property props = new Properties();

•

Specify the sending server:
– props.put(“mail.smtp.host”, URL of mail server);

•

Create a new session object from those properties:
– Session s = Session.getDefaultInstance(props);

•

Create new MimeMessage object from session
– MimeMessage message = new MimeMessage(s);


Common properties
• mail.transport.protocol: specifies the protocol that’s used
for the session
• mail.smtp.host: specifies the host computer for SMTP
server
• mail.smtp.port: specifies the port that the SMTP server is
using
• mail.smtp.auth: specifies whether authentication is
required to log in to the SMTP server
• mail.smtp.quitwait: this property can be set to false to
prevent an SSLException from occurring when you
attempt to connect to a Gmail SMTP server

• To set the properties of Properties object, you
can use the put method to specify of a property
name and value
• The static getDefaultInstance method of the
Session class returns the default Session object
for the application
• The setDebug method of the Session object can
be used to print debugging information about the
session to a log file
• If you change the properties for a Session
object, you must restart Tomcat before the
changes take effect
• If the Java application is running on the same
computer as the SMTP server, you can use the
localhost keyword to specify the SMTP host.


Setting Message Components
•

Set the subject:
– message.setSubject(“subject”);

•

Set the message text:
– message.setText(“Thanks for your
order!”); //”text/plain”

•

Could also be html or other types
– Will need to specify MIME type

String response =
“<html><head><title>Reciept>Thank you for your order!”;
message.setContent(response, “text/html”);


Setting Addresses
• Use setRecipient method
– Specify internet address of recipient
• Must use InternetAddress class
• InternetAddress constructor requires email address, can also optionally
give name

– Specify TO, CC, or BCC
– Can add multiple recipients
Message.setRecipient(Message.RecipientType.TO,
new InternetAddress(“
”));
Message.setRecipient(Message.RecipientType.CC,
new InternetAddress(, “Barney
Rubble”));


Setting Addresses
•

Address can also be a list
– Good for mailing lists
– Array of type Address

•

Use setRecipients method

Address[] list = new Address[size of mailing list];
for (int i = 0; i < size of mailing list; i++) {
list[i] = get next address for file;
}
Message.setRecipients(Message.RecipientType.TO, list);

• Use addRecipient method
Message.addRecipient(Message.RecipientType.TO,
new InternetAddress(“”) )
Using addRecipient/addRecipients to add email addresses to any
existing addresses for a message


Sending Messages
•

Simple method:
Transport.send(message);

•

More complex method if server requires authentication:

– Create Transport object from sessions
Transport t = session.getTransport();
– Connect to server with name and password
t.connect(“your name”, “your password”);
– Send the message
t.sendMessage(message, message.getAllRecipients());