1. pom.xml

发送模板邮件需要用到spring-boot-starter-thymeleaf，其他其他邮件内容不需要该依赖

<!-- mail -->
<dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-mail</artifactId>
</dependency>
<!-- thymeleaf -->
<dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>

2. application.properties

spring.mail.host=邮箱服务器
spring.mail.username=邮箱用户名
spring.mail.password=邮箱授权码
spring.mail.properties.mail.smtp.auth=true
spring.mail.properties.mail.smtp.starttls.enable=true
spring.mail.properties.mail.smtp.starttls.required=true

3.MailUtil

@Component
public class MailUtil {

    private final Logger logger = LoggerFactory.getLogger(getClass());

    @Resource
    private JavaMailSender javaMailSender;

    @Resource
    private TemplateEngine templateEngine;

    /**
     * 发送简单邮件
     * @param sender 发送人
     * @param receiver 接收人
     * @param carbonCopy 抄送人
     * @param subject 主题
     * @param text 内容
     */
    public void sendSimpleEmail(String sender, String[] receiver, String[] carbonCopy, String subject, String text){
        long startTimestamp = System.currentTimeMillis();
        logger.info("{} Start send mail ... ", startTimestamp);

        try {
            SimpleMailMessage message = new SimpleMailMessage();
            message.setFrom(sender);
            message.setTo(receiver);
            message.setCc(carbonCopy);
            message.setSubject(subject);
            message.setText(text);

            javaMailSender.send(message);

            logger.info("{} Send mail success", System.currentTimeMillis());
        } catch (Exception e) {
            e.printStackTrace();
            logger.error("Send mail failed, error message is : {} \n", e.getMessage());
        }
    }

    /**
     * 发送html邮件
     * @param sender
     * @param receiver
     * @param carbonCopy
     * @param subject
     * @param text
     * @param isHtml
     */
    public void sendHtmlEmail(String sender, String[] receiver, String[] carbonCopy, String subject, String text, boolean isHtml){
        long startTimestamp = System.currentTimeMillis();
        logger.info("{} Start send mail ... ", startTimestamp);

        try {
            MimeMessage message = javaMailSender.createMimeMessage();
            MimeMessageHelper mimeMessageHelper = new MimeMessageHelper(message);

            mimeMessageHelper.setFrom(sender);
            mimeMessageHelper.setTo(receiver);
            mimeMessageHelper.setCc(carbonCopy);
            mimeMessageHelper.setSubject(subject);
            mimeMessageHelper.setText(text, isHtml);

            javaMailSender.send(message);

            logger.info("{} Send mail success", System.currentTimeMillis());
        } catch (Exception e) {
            e.printStackTrace();
            logger.error("Send mail failed, error message is : {} \n", e.getMessage());
        }
    }

    /**
     * 发送带附件的邮件
     * @param sender
     * @param receiver
     * @param carbonCopy
     * @param subject
     * @param text
     * @param isHtml
     * @param fileName
     * @param file
     */
    public void sendAttachmentFileEmail(String sender, String[] receiver, String[] carbonCopy, String subject, String text, boolean isHtml, String fileName, File file){
        long startTimestamp = System.currentTimeMillis();
        logger.info("{} Start send mail ... ", startTimestamp);

        try {
            MimeMessage message = javaMailSender.createMimeMessage();
            MimeMessageHelper mimeMessageHelper = new MimeMessageHelper(message);

            mimeMessageHelper.setFrom(sender);
            mimeMessageHelper.setTo(receiver);
            mimeMessageHelper.setCc(carbonCopy);
            mimeMessageHelper.setSubject(subject);
            mimeMessageHelper.setText(text, isHtml);
            mimeMessageHelper.addAttachment(fileName, file);

            javaMailSender.send(message);

            logger.info("{} Send mail success", System.currentTimeMillis());
        } catch (Exception e) {
            e.printStackTrace();
            logger.error("Send mail failed, error message is : {} \n", e.getMessage());
        }
    }

    /**
     * 发送模板邮件
     * @param sender
     * @param receiver
     * @param carbonCopy
     * @param subject
     * @param template
     * @param context
     */
    public void sendTemplateEmail(String sender, String[] receiver, String[] carbonCopy, String subject, String template, Context context){
        long startTimestamp = System.currentTimeMillis();
        logger.info("{} Start send mail ... ", startTimestamp);

        try {
            MimeMessage message = javaMailSender.createMimeMessage();
            MimeMessageHelper mimeMessageHelper = new MimeMessageHelper(message);

            String text = templateEngine.process(template, context);

            mimeMessageHelper.setFrom(sender);
            mimeMessageHelper.setTo(receiver);
            mimeMessageHelper.setCc(carbonCopy);
            mimeMessageHelper.setSubject(subject);
            mimeMessageHelper.setText(text, true);

            javaMailSender.send(message);

            logger.info("{} Send mail success", System.currentTimeMillis());
        } catch (Exception e){
            e.printStackTrace();
            logger.error("Send mail failed, error message is : {} \n", e.getMessage());
        }
    }

}

转载
Spring Boot入门教程(二十七): Mail