因此，我尝试使用JavaMailSender、MimeMessage和MimeMessageHelper发送一封电子邮件，并在邮件末尾添加一个取消订阅的可单击链接。

package com.emailScheduler.emailScheduler.Service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.mail.SimpleMailMessage;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.mail.javamail.MimeMessageHelper;
import org.springframework.stereotype.Service;
import org.thymeleaf.spring5.SpringTemplateEngine;

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

@Service
public class MailService {

    @Autowired
    private JavaMailSender javaMailSender;

    @Autowired
    private SpringTemplateEngine springTemplateEngine;

    //Simple mail sender method
    public void sendMail(String to, String sub, String msg){
        SimpleMailMessage mailMessage = new SimpleMailMessage();

        mailMessage.setFrom("Sender Name");
        mailMessage.setTo(to);
        mailMessage.setSubject(sub);
        mailMessage.setText(msg);

        javaMailSender.send(mailMessage);
    }

    //HTML mail sender method
    public void sendMail2 (String to, String sub, String msg) throws MessagingException, UnsupportedEncodingException {

        MimeMessage mailMessage = javaMailSender.createMimeMessage();
        MimeMessageHelper messageHelper = new MimeMessageHelper(mailMessage);

        /*Context context = new Context();
        context.setVariables(mailModel);*/

        String html =  "<p>" + msg + "</p>" + "<a href= \"localhost:8080/unsubscribe\">unsubscribe1</a>";
        String html2 = "<p>" + msg + "</p>" + "<a href= 'localhost:8080/unsubscribe'>unsubscribe2</a>";
        String html3 = html + html2;

        messageHelper.setFrom("senderemail@gmail.com", "Sender Name");
        messageHelper.setTo(to);
        messageHelper.setSubject(sub);
        messageHelper.setText(html3, true);

        System.out.println(html);
        System.out.println(html2);

        javaMailSender.send(mailMessage);
    }
}

我可以成功发送电子邮件，但在我的邮件正文中，由于某种原因，unsubscribe没有显示为超链接，而是纯文本，在chrome浏览器的inspect元素中检查时，它显示如下<a>unsubscribe1</a>