Java class for sending email using Apache Commons.

Main.java

package br.com.murah.mail;

import java.io.File;
import java.io.FilenameFilter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import org.apache.commons.mail.DefaultAuthenticator;
import org.apache.commons.mail.EmailAttachment;
import org.apache.commons.mail.MultiPartEmail;

/**
 * Sends an email.
 * <p>
 * Default properties for gmail are used when none are provided.
 * 
 * @since Sep 6, 2016
 * @author Ulisses Lima
 */
public class Main {
	/**
	 * Extensions forbidden by gmail.
	 */
	public static String forbidden = ".*\\.sh|.*\\.exe|.*\\.bat|.*\\.jar|.*\\~";
	public static final FilenameFilter filter = new FilenameFilter() {
		public boolean accept(File dir, String name) {
			return !name.matches(forbidden);
		}
	};

	public static void main(String[] args) throws Exception {
		boolean html = getBool("html", false);
		String server = get("server", "smtp.gmail.com");
		int port = getInt("port", 465);
		String user = get("user");
		String password = get("password");
		boolean ssl = getBool("ssl", true);
		boolean tls = getBool("tls", false);
		String from = get("from", "me");
		String[] to = getArray("to");
		String[] cc = getArray("cc");
		String[] bcc = getArray("bcc");
		String subject = get("subject");
		String message = get("message");
		File[] attachments = getAttachments();

		MultiPartEmail email = new MultiPartEmail();
		email.setHostName(server);
		email.setSmtpPort(port);
		email.setAuthenticator(new DefaultAuthenticator(user, password));
		email.setSSLOnConnect(ssl);
		if (tls) {
			email.setStartTLSEnabled(tls);
			email.setStartTLSRequired(tls);
		}
		email.setFrom(from);
		email.setSubject(subject);
		if (html)
			email.setContent(message, "text/html; charset=utf-8");
		else
			email.setMsg(message);
		email.addTo(to);
		email.addReplyTo(to[0]);
		if (cc != null)
			email.addCc(cc);
		if (bcc != null)
			email.addBcc(bcc);

		for (File file : attachments) {
			EmailAttachment attachment = new EmailAttachment();
			attachment.setDisposition(EmailAttachment.ATTACHMENT);
			attachment.setPath(file.getAbsolutePath());
			attachment.setDescription(file.getPath());
			attachment.setName(file.getName());
			email.attach(attachment);
		}

		email.send();
	}

	public static String get(String prop, String defaultValue) {
		return System.getProperty(prop, defaultValue);
	}

	public static String get(String prop) {
		return get(prop, "unspecified");
	}

	public static String[] getArray(String prop) {
		String string = get(prop, null);
		if (string == null)
			return null;

		if (string.contains(";")) {
			return string.split(";");
		}
		return string.split(",");
	}

	public static int getInt(String prop, int defaultValue) {
		return Integer.parseInt(get(prop, String.valueOf(defaultValue)));
	}

	public static boolean getBool(String prop, boolean defaultValue) {
		return Boolean.valueOf(get(prop, String.valueOf(defaultValue)))
				.booleanValue();
	}

	/**
	 * @return found files.
	 * @since Sep 6, 2016
	 * @author Ulisses Lima
	 */
	private static File[] getAttachments() {
		String attachParam = get("attach");
		if (attachParam == null || attachParam.length() < 1)
			return new File[0];

		String[] filenames = attachParam.split(";");
		List<File> files = new ArrayList<File>(filenames.length);

		for (int i = 0; i < filenames.length; i++) {
			File file = new File(filenames[i]);
			if (!file.exists())
				continue;

			if (file.getName().matches(forbidden))
				continue;

			if (file.isDirectory()) {
				files.addAll(Arrays.asList(file.listFiles(filter)));
			} else {
				files.add(file);
			}
		}
		return files.toArray(new File[] {});
	}
}