1. 导入相关依赖

<dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-mail</artifactId>
      <version>2.6.3</version>
</dependency>

2. 打开邮箱设置

3. 编写配置文件

spring.mail.host=smtp.qq.com
spring.mail.username=用户名
spring.mail.password=这里填邮箱的授权码，不是密码！
spring.mail.protocol=smtps
spring.mail.properties.mail.smtp.auth=true
spring.mail.properties.mail.smtp.starttls.enable=true
spring.mail.properties.mail.smtp.starttls.required=true

4. 完成发送邮件功能

@Component
public class MailClient {

    //java提供的发送邮件的接口
    @Autowired
    private JavaMailSender mailSender;

    //将配置文件中邮件发送方的邮箱地址配置到类中
    @Value("${spring.mail.username}")
    private String from;

    /**
     *
     * @param to 接收方
     * @param subject 标题
     * @param content 内容
     */
    public void sendMail(String to, String subject, String content) {
        MimeMessage message = mailSender.createMimeMessage();
        MimeMessageHelper helper = new MimeMessageHelper(message);
		
        try {
            helper.setFrom(from);
            helper.setTo(to);
            helper.setSubject(subject);
            helper.setText(content, true);//设置为true： 开启发送html页面功能
            mailSender.send(helper.getMimeMessage());
        } catch (MessagingException e) {
            e.printStackTrace();
        }
    }

}

5. 测试

public class MailUtilTest {

    @Autowired
    private MailUtil mailUtil;

    //模板引擎，用来解析thymeleafs下的html文件
    @Autowired
    private TemplateEngine templateEngine;


    /*
    简单的测试，只是发送一些文本内容：“发送成功”
    */
    @Test
    public void test1() {
        mailUtil.sendMail("xxxxxx@163.com", "TEST", "发送成功！");
    }


    /*
    常用：发送html页面
    */
    @Test
    public void test2() {
        Context context = new Context();
        //设置html中参数
        context.setVariable("username", "吴京");
        //将html和context封装成一个字符串
        String content = templateEngine.process("/mail/demo", context);
        //发送邮件
        mailUtil.sendMail("xxxxxxx@163.com", "TEST", content);

    }


}