工具类代码

@Component
public class MailClient {

    private static final Logger logger = LoggerFactory.getLogger(MailClient.class);

    @Autowired
    private JavaMailSender mailSender;

    @Value("${spring.mail.username}")
    private String from;

    public void sendMail(String to, String subject, String content) {
        try {
            MimeMessage message = mailSender.createMimeMessage();
            MimeMessageHelper helper = new MimeMessageHelper(message);
            helper.setFrom(from);
            helper.setTo(to);
            helper.setSubject(subject);
            helper.setText(content, true);
            mailSender.send(helper.getMimeMessage());
        } catch (MessagingException e) {
            logger.error("发送邮件失败:" + e.getMessage());
        }
    }

}

配置文件配置基本属性

spring.mail.host=smtp.zzz.com
spring.mail.port=465
#发送者邮箱，邮箱地址与host对应
spring.mail.username=xxx@zzz.com
spring.mail.password=******
spring.mail.protocol=smtps
spring.mail.properties.mail.smtp.ssl.enable=true

结合模板引擎发送html邮件

@Autowired
private MailClient mailClient;

@Autowired
private TemplateEngine templateEngine;

@Test
//发送普通邮件
public void testTextMail() {
    mailClient.sendMail("xxx@zzzz.com", "TEST", "Welcome.");
}

@Test
//发送html邮件
public void testHtmlMail() {
    Context context = new Context();
    context.setVariable("username", "zhangsan");
    // 模板地址
    String content = templateEngine.process("/mail/demo", context);
    System.out.println(content);

    mailClient.sendMail("xxx@zzzz.com", "HTML", content);
}