Spring Boot发送邮件

1. pom

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

2.application.properties

#这里以qq邮箱为例
# qq邮箱服务器
spring.mail.host=smtp.qq.com
# 你的qq邮箱账户
spring.mail.username=yourAccount@qq.com
# 你的qq邮箱第三方授权码
spring.mail.password=yourPassword
# 编码类型
spring.mail.default-encoding=UTF-8

3. 开启邮箱第三方支持以及获取授权码（以QQ邮箱为例）

4. 代码编写

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.core.io.FileSystemResource;
import org.springframework.mail.SimpleMailMessage;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.mail.javamail.MimeMessageHelper;
import org.springframework.stereotype.Service;

import javax.mail.MessagingException;
import javax.mail.internet.MimeMessage;
import java.io.File;

/**
 * @author zhaokuii11@163.com
 * @create 2022-01-11 19:22
 * @Description
 */
@Service
public class MailUtils {
    // 日志
    private final Logger logger = LoggerFactory.getLogger(MailUtils.class);
    @Value("${spring.mail.username}") //注入 application.properties中指定的用户名
    private String from;

    @Autowired //用于发送文件
    private JavaMailSender mailSender;


    /**
     * 发送普通文本邮件
     *
     * @param to      收件人
     * @param subject 主体
     * @param content 内容
     */
    public void sendSimpleMail(
            String to, String subject, String content
    ) {

        SimpleMailMessage message = new SimpleMailMessage();
        message.setTo(to);//收信人
        message.setSubject(subject);//主题
        message.setText(content);//内容
        message.setFrom(from);//发信人

        mailSender.send(message);
    }

    /**
     * 发送html邮件
     *
     * @param to      收件人
     * @param subject 书体
     * @param content 内容(可以包含html等标签)
     */
    public void sendHtmlMail(
            String to, String subject, String content
    ) {
        //使用MimeMessage，MIME协议
        MimeMessage message = mailSender.createMimeMessage();
        MimeMessageHelper helper;
        //MimeMessageHelper帮助我们设置更丰富的内容
        try {
            helper = new MimeMessageHelper(message, true);
            helper.setFrom(from);
            helper.setTo(to);
            helper.setSubject(subject);
            helper.setText(content, true);//true代表支持html
            mailSender.send(message);
            logger.info("发送HTML邮件成功");
        } catch (MessagingException e) {
            e.printStackTrace();
            logger.error("发送HTML邮件失败：", e);
        }

    }


    /**
     * 发送带附件的邮件
     *
     * @param to       收件人
     * @param subject  主体
     * @param content  内容
     * @param filePath 附件路径
     */
    public void sendAttachmentMail(
            String to, String subject,
            String content, String filePath
    ) {
        // 日志
        logger.info("发送带附件邮件开始：{},{},{},{}", to, subject, content, filePath);
        MimeMessage message = mailSender.createMimeMessage();

        MimeMessageHelper helper;
        try {
            helper = new MimeMessageHelper(message, true);
            //true代表支持多组件，如附件，图片等
            helper.setFrom(from);
            helper.setTo(to);
            helper.setSubject(subject);
            helper.setText(content, true);
            FileSystemResource file = new FileSystemResource(new File(filePath));
            String fileName = file.getFilename();
            helper.addAttachment(fileName, file);//添加附件，可多次调用该方法添加多个附件
            mailSender.send(message);
            logger.info("发送带附件邮件成功");
        } catch (MessagingException e) {
            logger.error("发送带附件邮件失败", e);
        }

    }

    /**
     * 发送带图片的邮件
     *
     * @param to      收件人
     * @param subject 主体
     * @param content 内容
     * @param rscPath 图片路径
     * @param rscId   rscId 图片ID,用于在<img\>标签中使用，从而显示图片
     */
    public void sendInlineResourceMail(
            String to, String subject, String content,
            String rscPath, String rscId) {
        // 日志
        logger.info("发送带图片邮件开始：{},{},{},{},{}", to, subject, content, rscPath, rscId);
        MimeMessage message = mailSender.createMimeMessage();

        MimeMessageHelper helper;
        try {
            helper = new MimeMessageHelper(message, true);
            helper.setFrom(from);
            helper.setTo(to);
            helper.setSubject(subject);
            helper.setText(content, true);
            FileSystemResource res = new FileSystemResource(new File(rscPath));
            helper.addInline(rscId, res);//重复使用添加多个图片
            mailSender.send(message);
            logger.info("发送带图片邮件成功");
        } catch (MessagingException e) {
            logger.error("发送带图片邮件失败", e);
        }
    }
}

5. 测试

/**
 * @author zhaokuii11@163.com
 * @create 2022-01-11 19:49
 * @Description
 */
@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringBootApplicationTest {
    @Autowired
    MailUtils mailUtils;

    /**
     * 发送简单纯文本邮件
     */
    @Test
    public void sendSimpleMail() {
        mailUtils.sendSimpleMail("zhaokuii11@163.com", "发送邮件测试", "大家好，这是我用springboot进行发送邮件测试");
    }

    /**
     * 发送HTML邮件
     */
    @Test
    public void sendHtmlMail() {
        String content = "<html><body><h3><font color=\"red\">" + "大家好，这是springboot发送的HTML邮件" + "</font></h3></body></html>";
        mailUtils.sendHtmlMail("zhaokuii11@163.com", "发送邮件测试", content);
    }

    /**
     * 发送带附件的邮件
     */
    @Test
    public void sendAttachmentMail() {
        String content = "<html><body><h3><font color=\"red\">" + "大家好，这是springboot发送的HTML邮件，有附件哦" + "</font></h3></body></html>";
        String filePath = "your file path";
        mailUtils.sendAttachmentMail("zhaokuii11@163.com", "发送邮件测试", content, filePath);
    }

    /**
     * 发送带图片的邮件
     */
    @Test
    public void sendInlineResourceMail() {
        String rscPath = "your picture path";
        String rscId = "001";
        String content = "<html><body><h3><font color=\"red\">" + "大家好，这是springboot发送的HTML邮件，有图片哦" + "</font></h3>"
                + "<img src=\'cid:" + rscId + "\'></body></html>";
        mailUtils.sendInlineResourceMail("zhaokuii11@163.com", "发送邮件测试", content, rscPath, rscId);
    }
}

6. 发送模板邮件

• 以Thymeleaf模板引擎为例来讲解（具体语法自行了解）

6.0 导入 thymeleaf依赖

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

6.1 在templates文件夹下创建emailTemplate.html

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>邮件模板</title>
</head>
<body>
您好，感谢您的注册，这是一封验证邮件，请点击下面的链接完成注册，感谢您的支持！<br>
<a href="#" th:href="@{http://www.bestbpf.com/register/{id}(id=${id})}">激活账户</a>
</body>
</html>

6.2 测试

    @Autowired
    private TemplateEngine templateEngine;
    @Autowired
    MailUtils mailUtils;

    /**
     * 指定模板发送邮件
     */
    /**
     * 指定模板发送邮件
     */
    @Test
    public void testTemplateMail() {
        //向Thymeleaf模板传值，并解析成字符串
        Context context = new Context();
        context.setVariable("id", "001");
        String emailContent = templateEngine.process("emailTemplate", context);
        mailUtils.sendHtmlMail("zhaokuii11@163.com", "这是一个模板文件", emailContent);
    }

参考
https://www.jianshu.com/p/59d15b357201