Mail.java

package me.xhh.mail;

import java.util.Map;
import java.util.Properties;

import javax.mail.Address;
import javax.mail.AuthenticationFailedException;
import javax.mail.Authenticator;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

import me.xhh.mail.TemplateHandler.MailTemplate;
import me.xhh.utils.Util;

import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class Mail {

	private static final String SMTP_HOST_NAME = "TODO";
	private static final String SMTP_AUTH_USER = "TODO";
	private static final String SMTP_AUTH_PWD = "TODO";
	private static final String SMTP_SEND_FROM = "TODO";

	private static final Logger log = LoggerFactory.getLogger(Mail.class);

	private static void postMail(String[] recipients, String[] replyTo, String subject, String message, String fromEmail,
			boolean htmlMail) throws MessagingException, AuthenticationFailedException {

		boolean debug = false;

		Properties props = new Properties();
		// use this to prevent the [MessagingException: 501 Syntax: HELO hostname]
		props.put("mail.smtp.localhost", SMTP_HOST_NAME);
		props.put("mail.smtp.host", SMTP_HOST_NAME);
		props.put("mail.smtp.auth", "true");

		Authenticator auth = new SMTPAuthenticator(SMTP_AUTH_USER, SMTP_AUTH_PWD);
		// use Session.getInstance instead of Session.getDefaultInstance to 
		// get rid of [SecurityException: Access to default session denied]
		Session session = Session.getInstance(props, auth);
		session.setDebug(debug);

		// create a message
		Message msg = new MimeMessage(session);

		// check and set the from
		if (fromEmail == null)
			fromEmail = SMTP_SEND_FROM;
		InternetAddress addressFrom = new InternetAddress(fromEmail);
		msg.setFrom(addressFrom);

		// set recipients
		InternetAddress[] addressTo = new InternetAddress[recipients.length];
		for (int i = 0; i < recipients.length; i++)
			addressTo[i] = new InternetAddress(recipients[i]);
		msg.setRecipients(Message.RecipientType.TO, addressTo);

		// check and set reply-to
		if (replyTo != null && replyTo.length > 0) {
			Address[] replyToAddresses = new Address[replyTo.length];
			for (int i = 0; i < replyTo.length; i++)
				replyToAddresses[i] = new InternetAddress(replyTo[i]);
			msg.setReplyTo(replyToAddresses);
		}

		// Setting the Subject and Content Type
		msg.setSubject(subject);
		msg.setContent(message, htmlMail ? "text/html;charset=utf-8" : "text/plain;charset=utf-8");

		// send mail
		Transport.send(msg);
	}

	public static void sendInThread(String recipient, MailTemplate template, Map<String, Object> mailData) {
		sendInThread(new String[]{recipient}, template, mailData);
	}

	public static void sendInThread(final String[] recipients, final MailTemplate template, final Map<String, Object> mailData) {
		new Thread() {
			public void run() {
				send(recipients, template, mailData);
			}
		}.start();
	}

	public static boolean send(String recipient, MailTemplate template, Map<String, Object> mailData) {
		return send(new String[]{recipient}, template, mailData);
	}

	public static boolean send(String[] recipients, MailTemplate template, Map<String, Object> mailData) {
		log.info("sending email with template: {}", template);
		String data;
		try {
			data = TemplateHandler.processTemplate(template, mailData);
		} catch (Exception e) {
			log.error("Failed to process the email template: " + template, e);
			return false;
		}

		int pos = data.indexOf("\n");
		String subject = data.substring(0, pos).trim();
		String message = data.substring(pos + 1).trim();
		return send(recipients, subject, message);
	}

	public static boolean send(String[] recipients, String subject, String message) {
		boolean sent;

		if (Util.DEBUG) {
			sent = true;
			log.debug("[Mail.send] Development env found, email is not sent actually.");
		} else {
			try {
				postMail(recipients, null, subject, message, null, false);
				sent = true;
			} catch (Exception e) {
				log.error("Failed to postMail! Subject: " + subject, e);
				sent = false;
			}
		}

		// log the email details
		Object[] logArgs = {sent ? "Email sent to:" : "Failed to send email to:", StringUtils.join(recipients, ','), subject, message};
		if (sent) {
			log.info("{} {}\nSubject: {}\n'''\n{}\n'''", logArgs);
		} else {
			log.error("{} {}\nSubject: {}\n'''\n{}\n'''", logArgs);
		}

		return true;
	}

}

/**
 * SimpleAuthenticator is used to do simple authentication when the SMTP server requires it.
 */
class SMTPAuthenticator extends javax.mail.Authenticator {
	private String username;
	private String password;

	public SMTPAuthenticator(String smtpAuthUser, String smtpAuthPwd) {
		this.username = smtpAuthUser;
		this.password = smtpAuthPwd;
	}

	@Override
	public PasswordAuthentication getPasswordAuthentication() {
		return new PasswordAuthentication(username, password);
	}
}