Using JavaMail in Website forms

BANGALORE, INDIA: While building Web sites, Java developers have to sometimes provide functionality of allowing user to submit feedback by an email account; or a functionality wherein logged-in users can send messages as emails to customers or clients from a common account. For providing such functionality there's a Java API called JavaMail API. It provides a mail and messaging framework that can be used to send messages from the host mail server.

For cases where the website hosting provider does not provide a mail server, developers are forced to save the users' feedback to a database and retrieve information from there later. In such a situation Google Mail comes to the rescue. In this article we will see through a demo app how to incorporate a user's feedback form submission through the JavaMail API and the feedback data being sent to a Gmail account.

About JavaMail API

JavaMail API provides a complete set of abstract classes defining objects that would comprise a complete mail system. With this API, Java has given developers a platform from which they can create their own mailing system app that can not only send but also receive messages. The JavaMail API has support for different messaging system implementations like Message class for messaging details such as subject line, etc, store class for different message privileges like read, write, etc, and Transport class for message sending over a particular protocol.

JavaMail subclasses also expose additional messaging system features, for instance, the MimeMessage sub class that exposes and implements characteristics of an Internet mail message that are as per RFC822 and MIME standards. Developers can now subclass the JavaMail classes to provide them with implementations for particular messaging systems, such as IMAP, POP3, and SMTP. By using these abstract classes the base can be configured for defining the client application for a messaging system.

Setup and Configuration

For the demo app we will build a component of the website that will have a feedback form designed in JSP, which we'll call the 'Java Servlet.' This will use JavaMail to send the form-data as an email. The web server for the demo will be Tomcat. For this purpose let's first do some basic configuration of the APIs. With this month's PCQ_PRFESSIONAL CD we have provided JavaMail API version 1.4 along with Java Activation Framework (JAF) version 1.1.1 zip files. Extract the zip files to some base folder and then append the paths to the Classpath entry for system environment variables pointing to mail.jar under JAVA_MAIL/bin folder and activation.jar under JAF/bin folder.

Now from within Eclipse IDE start a new project from File > New > Project and then select Tomcat project (considering that the Tomcat-Eclipse plug-in is installed). Name the project as 'JavaMail.' As we intend to deploy our app on a hosting service provider's server, we will have to pack the JavaMail APIs into the WAR file so that during deployment the programs could get reference to the JavaMail libraries. For this reason copy the mail.jar and activation.jar files into the WEB-INF/lib folder. Also add these two jar files into the project's classpath. Once this initial configuration of the project 'JavaMail' has been completed we can now start building our Web app.

Designing the form and its Servlet

The feedback form for the demo app is simple with two input fields for taking sender's e-mail address and his name, while the text area will be used for taking the user's feedback/comment. Name the fields appropriately so that their values can be retrieved by the Servlet while sending the mail. On the form's action attribute set the mapped path that will call for the Servlet. Now let's start coding for the Servlet that will retrieve the values from the feedback form and will send them across to an email account

For the demo app we are using Google Mail as the mail server to send mails. To send mails via Gmail, the SMTP mail protocol is used and the port for that on Gmail server is 465 and the host is smtp.gmail.com. The email account we refer here as 'demoaccount' is just for reference. Also Google only allows messages to be sent over SSL, so we will have to enable it. Also we have to login into the Gmail account and after authentication only the mail could be sent, so for this we will use Authentication also and set the property for that as true. Once the message is sent the transporter waits for a QUIT command, we can close the connection immediately by setting the quitwait property as false. Now with initial properties configured, we can proceed by sending the message. Let's look at the demo Servlet first then we will discuss some of the parameters used in that.

public class SendMailServlet extends HttpServlet

{ ...

public void service(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException{ senderName=request.getParameter("name");

comment=request.getParameter("comment");

String to="demoaccount@gmail.com";

String from="demoacc@gmail.com";

String host = "smtp.gmail.com";

Properties p = new Properties();

p.put("mail.smtp.host", host);

p.put("mail.smtp.port", "465");

p.put("mail.smtp.starttls.enable","true");

p.put("mail.smtp.auth", "true");

p.put("mail.smtp.debug", "true");

p.put("mail.smtp.socketFactory.port", "465");

p.put("mail.smtp.socketFactory.class","javax.net.ssl.SSLSocketFactory");

p.put("mail.smtp.socketFactory.fallback", "false");

p.put("mail.debug", "true");

p.setProperty("mail.smtp.quitwait", "false");

SecurityManager security = System.getSecurityManager();

try {Authenticator auth = new SMTPAuthenticator(); Session session = Session. getInstance(p, auth);

MimeMessage msg = new MimeMessage(session);

msg.setFrom(new InternetAddress(from));

InternetAddress<> address = {new InternetAddress(to)};

msg.setRecipints(Message.RecipientType.TO, address);

msg.setSubject("Test Mail");

msg.setSentDate( new Date() );

message.setContent(comment,“mptext/plain");

msg.saveChanges();

Transport.send(msg);

System.out.println("Mail Send Successfully....");

}

catch (MessagingException mex) { mex.printStackTrace();

System.out.println("Mail not sent");}

} //service ends here}

For the above code mention the init() and destroy() method also. Then in the Properties we have set all the parameters for forwarding the mail. The MimeMessage initiates the session that will use the Properties parameters and set the values from the feedback form and configure the message body. The Transport will send the message over the set protocol, in our case SMTP. As we use Authenticator class named as SMTPAuthenticator for password verification, let's define the same.

class SMTPAuthenticator extends javax.mail.Authenticator {

public PasswordAuthentication getPasswordAuthentication() {

return new PasswordAuthentication( "demoaccount", "password");

}

This way we can use JavaMail to send the feedback of a user as e-mail message to a Gmail account. Even when the web hosting provider does not facilitate you with a mail server you have JavaMail and Gmail to implement the mailing system for Web app.

In Conclusion

JavaMail API provides facility with which a developer can configure a complete mail system for sending/receiving mails over standard mail protocols. It's a great way to enhance your Web applications.