История изменений

Исправление Nagwal, 18.03.15 10:02 (текущая версия) :

Да, возможно, гуглить по слову javax.mail

Вот пример, правда не standalone а сконфигуренный спрингом бин, да еще и freemarker использующий для шаблонизации, но думаю разберешся

package ru.visang.services;

import freemarker.template.Configuration;
import freemarker.template.Template;
import freemarker.template.TemplateException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;
import ru.visang.commons.exceptions.ExpectedException;
import ru.visang.commons.utils.LambdaUtils;

import javax.annotation.PostConstruct;
import javax.mail.*;
import javax.mail.internet.AddressException;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import java.io.File;
import java.io.IOException;
import java.io.StringWriter;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Properties;

import static java.util.stream.Collectors.joining;
import static ru.visang.commons.utils.LambdaUtils.doUnsafe;

/**
 * Email sending service.
 *
 *
 * Created by Antony on 12.11.2014.
 */
@Service
public class NotificationService {

    @Value("${email.smtp.hostname}")
    private String hostname;

    @Value("${email.smtp.port}")
    private Integer port;

    @Value("${email.smtp.login}")
    private String  login;

    @Value("${email.smtp.password}")
    private String password;

    @Value("${email.smtp.use_tls}")
    private Boolean usetls;

    @Value("${email.smtp.use_auth}")
    private Boolean auth;

    @Value("${email.mail.from}")
    private String mailFrom;

    @Value("${email.enabled}")
    private boolean enabled;

    @Value("${email.template.path}")
    private String templateDir;

    private Session session;

    private Configuration fmConfig;

    private Logger log = LoggerFactory.getLogger(getClass());

    @PostConstruct
    protected void init() {
        if (enabled) {
            log.info("=====> Initializing Email notification service.");
            fmConfig = new Configuration();
            fmConfig.setDefaultEncoding("UTF-8");
            try {
                fmConfig.setDirectoryForTemplateLoading(new File(templateDir));
            } catch (IOException e) {
                log.error("======> Cannot set base directory for email notifications templates lookup.", e);
                throw new ExceptionInInitializerError();
            }

            Properties props = new Properties();

            props.put("mail.smtp.auth", auth.toString());
            props.put("mail.smtp.starttls.enable", usetls.toString());
            props.put("mail.smtp.host", hostname);
            props.put("mail.smtp.port", port.toString());

            if (auth) {
                session = Session.getInstance(props, new Authenticator() {
                    @Override
                    protected PasswordAuthentication getPasswordAuthentication() {
                        return new PasswordAuthentication(login, password);
                    }
                });
            } else {
                session = Session.getInstance(props);
            }
        } else {
            log.warn("=====> Email notifications are disabled.");
        }
    }

    /**
     * Enumeration of available notification types.
     */
    public static enum Type {
        FMS_SENT("fms_sent.ftl"), FMS_ACCEPTED("fms_accepted.ftl"), FMS_REJECTED("fms_rejected.ftl");

        private String template;

        Type(String template) {
            this.template = template;
        }

        public String template() {
            return template;
        }
    }

    /**
     * Send notifications to all acceptors
     *
     * @param type Type of notification
     * @param acceptors List of acceptors
     * @param properties Properties that should be substituted in template for this notification type
     */
    public void sendNotifications(Type type, List<String> acceptors, Map<String, Object> properties) {
        if (!enabled) return;

        Objects.requireNonNull(acceptors, "Acceptors list cannot be null.");
        Objects.requireNonNull(properties, "Properties cannot be null.");

        try {
            MimeMessage message = new MimeMessage(session);

            // Set From: header field of the header.
            message.setFrom(new InternetAddress(mailFrom));

            // Set To: header field of the header.
            acceptors.forEach(a -> doUnsafe(() -> message.addRecipient(Message.RecipientType.TO, new InternetAddress(a))));

            // Set Subject: header field
            message.setSubject("Visareg.ru notification!");

            Template template = fmConfig.getTemplate(type.template());

            StringWriter stringWriter = new StringWriter();
            template.process(properties, stringWriter);

            // Send the actual HTML message, as big as you like
            message.setContent(stringWriter.toString(), "text/html");

            // Send message
            Transport.send(message);
        } catch (MessagingException | IOException e) {
            log.error("=====> Error sending notification {} to users: {}. Error: {}", type.name(), acceptors.stream().collect(joining(", ")), e.getMessage());
        } catch (TemplateException e) {
            log.error("=====> Error sending notification {} to users: {}", type.name(), acceptors.stream().collect(joining(", ")), e);
            throw new ExpectedException("Template processing error.", e); //Let us fail if we have an error in template.
        }
    }

}

Исходная версия Nagwal, 18.03.15 10:00:

Да, возможно, гуглить по слову javax.mail

package ru.visang.services;

import freemarker.template.Configuration;
import freemarker.template.Template;
import freemarker.template.TemplateException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;
import ru.visang.commons.exceptions.ExpectedException;
import ru.visang.commons.utils.LambdaUtils;

import javax.annotation.PostConstruct;
import javax.mail.*;
import javax.mail.internet.AddressException;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import java.io.File;
import java.io.IOException;
import java.io.StringWriter;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Properties;

import static java.util.stream.Collectors.joining;
import static ru.visang.commons.utils.LambdaUtils.doUnsafe;

/**
 * Email sending service.
 *
 * This service can be used only form Controllers, not root Services because of dependency on FreemarkerViewResolver,
 * that needs to be initialized in WebContext to let it search for templates in a web folder and not only in classpath.
 *
 * Created by Antony on 12.11.2014.
 */
@Service
public class NotificationService {

    @Value("${email.smtp.hostname}")
    private String hostname;

    @Value("${email.smtp.port}")
    private Integer port;

    @Value("${email.smtp.login}")
    private String  login;

    @Value("${email.smtp.password}")
    private String password;

    @Value("${email.smtp.use_tls}")
    private Boolean usetls;

    @Value("${email.smtp.use_auth}")
    private Boolean auth;

    @Value("${email.mail.from}")
    private String mailFrom;

    @Value("${email.enabled}")
    private boolean enabled;

    @Value("${email.template.path}")
    private String templateDir;

    private Session session;

    private Configuration fmConfig;

    private Logger log = LoggerFactory.getLogger(getClass());

    @PostConstruct
    protected void init() {
        if (enabled) {
            log.info("=====> Initializing Email notification service.");
            fmConfig = new Configuration();
            fmConfig.setDefaultEncoding("UTF-8");
            try {
                fmConfig.setDirectoryForTemplateLoading(new File(templateDir));
            } catch (IOException e) {
                log.error("======> Cannot set base directory for email notifications templates lookup.", e);
                throw new ExceptionInInitializerError();
            }

            Properties props = new Properties();

            props.put("mail.smtp.auth", auth.toString());
            props.put("mail.smtp.starttls.enable", usetls.toString());
            props.put("mail.smtp.host", hostname);
            props.put("mail.smtp.port", port.toString());

            if (auth) {
                session = Session.getInstance(props, new Authenticator() {
                    @Override
                    protected PasswordAuthentication getPasswordAuthentication() {
                        return new PasswordAuthentication(login, password);
                    }
                });
            } else {
                session = Session.getInstance(props);
            }
        } else {
            log.warn("=====> Email notifications are disabled.");
        }
    }

    /**
     * Enumeration of available notification types.
     */
    public static enum Type {
        FMS_SENT("fms_sent.ftl"), FMS_ACCEPTED("fms_accepted.ftl"), FMS_REJECTED("fms_rejected.ftl");

        private String template;

        Type(String template) {
            this.template = template;
        }

        public String template() {
            return template;
        }
    }

    /**
     * Send notifications to all acceptors
     *
     * @param type Type of notification
     * @param acceptors List of acceptors
     * @param properties Properties that should be substituted in template for this notification type
     */
    public void sendNotifications(Type type, List<String> acceptors, Map<String, Object> properties) {
        if (!enabled) return;

        Objects.requireNonNull(acceptors, "Acceptors list cannot be null.");
        Objects.requireNonNull(properties, "Properties cannot be null.");

        try {
            MimeMessage message = new MimeMessage(session);

            // Set From: header field of the header.
            message.setFrom(new InternetAddress(mailFrom));

            // Set To: header field of the header.
            acceptors.forEach(a -> doUnsafe(() -> message.addRecipient(Message.RecipientType.TO, new InternetAddress(a))));

            // Set Subject: header field
            message.setSubject("Visareg.ru notification!");

            Template template = fmConfig.getTemplate(type.template());

            StringWriter stringWriter = new StringWriter();
            template.process(properties, stringWriter);

            // Send the actual HTML message, as big as you like
            message.setContent(stringWriter.toString(), "text/html");

            // Send message
            Transport.send(message);
        } catch (MessagingException | IOException e) {
            log.error("=====> Error sending notification {} to users: {}. Error: {}", type.name(), acceptors.stream().collect(joining(", ")), e.getMessage());
        } catch (TemplateException e) {
            log.error("=====> Error sending notification {} to users: {}", type.name(), acceptors.stream().collect(joining(", ")), e);
            throw new ExpectedException("Template processing error.", e); //Let us fail if we have an error in template.
        }
    }

}