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How to send an HTML email in Java (Using Google SMTP Server)

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In most of the business services sometimes there comes requirements to send notifications to users or administrators via email.

For example :
  • Confirming a user registration
  • Password reset via emails
Following code segments can be used to send these emails using Google SMTP server. Here I am sharing two ways to do it. 
  1. Using javax.mail.jar directly
  2. Using Apache commons email jar which wraps javax.mail 

Using javax.mail

try {
            Properties props = new Properties();
            props.put("mail.smtp.host", "smtp.gmail.com");
            props.put("mail.smtp.auth", "true");
            props.put("mail.debug", "false");
            props.put("mail.smtp.ssl.enable", "true");

            Session session = Session.getInstance(props, new EmailAuth());
            Message msg = new MimeMessage(session);

            InternetAddress from = new InternetAddress("sendersEmailAddress", "Sender's name");
            msg.setFrom(from);

            InternetAddress toAddress = new InternetAddress("Receiver's email");

            msg.setRecipient(Message.RecipientType.TO, toAddress);

            msg.setSubject("Test");
            msg.setContent(msg.setContent("<html>\n" +
                    "<body>\n" +
                    "\n" +
                    "<a href=\"http://pushpalankajaya.blogspot.com\">\n" +
                    "This is a link</a>\n" +
                    "\n" +
                    "</body>\n" +
                    "</html>", "text/html");, "text/html");
            Transport.send(msg);
        } catch (UnsupportedEncodingException ex) {
            ex.printStackTrace();

        } catch (MessagingException ex) {
            ex.printStackTrace();
        }
    }

    static class EmailAuth extends Authenticator {

        @Override
        protected PasswordAuthentication getPasswordAuthentication() {

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

        }
    }

Using Apache commons e-mail

        HtmlEmail email = new HtmlEmail();
        email.setHostName("smtp.gmail.com");
        email.setSmtpPort(465);
        email.setAuthenticator(new DefaultAuthenticator("sendersEmailAddress", "password"));
        email.setSSLOnConnect(true);
        email.setFrom("Senders' email");
        email.setSubject("TestMail- Alternative message");
        email.setHtmlMsg("<html>\n" +
                "<body>\n" +
                "\n" +
                "<a href=\"http://pushpalankajaya.blogspot.com\">\n" +
                "This is a link</a>\n" +
                "\n" +
                "</body>\n" +
                "</html>");
        // set the alternative message
        email.setTextMsg("This is a link: http://pushpalankajaya.blogspot.com");
        email.addTo("lanka@wso2.com");
        email.send();

Here with setTextMsg method we can set a plain text message to be shown at receiver's end if receiver is not supporting HTML content in emails.

If the gmail account used to send the email is 2-Step verification enabled and you used your usual password to send the email in code, you will get a similar error to the following.

javax.mail.AuthenticationFailedException: 534-5.7.9 Application-specific password required. Learn more at 534 5.7.9 http://support.google.com/accounts/bin/answer.py?answer=185833

The solution is to go to Account>Security>App passwords>Settings and generate a password for the app we are to run. 
Reference
[1] - http://www.oracle.com/webfolder/technetwork/tutorials/obe/java/javamail/javamail.html
[2] - http://commons.apache.org/proper/commons-email/userguide.html





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Published at DZone with permission of Pushpalanka Jayawardhana, DZone MVB. See the original article here.

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