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

import jakarta.mail.*;
import jakarta.mail.internet.*;
import java.util.Properties;

public class MailExample {
    public static void sendTextMail() {
        String host = "smtp.gmail.com";  // SMTP 服務(wù)器地址
        String from = "your_email@gmail.com";
        String password = "your_password";// 開啟SMTP 申請的密鑰
        String to = "recipient_email@gmail.com";

        // 配置屬性
        Properties props = new Properties();
        props.put("mail.smtp.host", host);
        props.put("mail.smtp.port", "587");
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.starttls.enable", "true");

        // 獲取會話對象
        Session session = Session.getInstance(props, new Authenticator() {
            @Override
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(from, password);
            }
        });

        try {
            // 創(chuàng)建郵件
            Message message = new MimeMessage(session);
            message.setFrom(new InternetAddress(from));
            message.setRecipients(Message.RecipientType.TO, InternetAddress.parse(to));
            message.setSubject("Java Mail 測試");
            message.setText("這是一封通過 Java Mail 發(fā)送的簡單文本郵件！");

            // 發(fā)送郵件
            Transport.send(message);
            System.out.println("郵件發(fā)送成功！");
        } catch (MessagingException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        sendTextMail();
    }
}

public static void sendHtmlMail() {
    String host = "smtp.gmail.com";
    String from = "your_email@gmail.com";
    String password = "your_password";// 開啟SMTP 申請的密鑰
    String to = "recipient_email@gmail.com";

    Properties props = new Properties();
    props.put("mail.smtp.host", host);
    props.put("mail.smtp.port", "587");
    props.put("mail.smtp.auth", "true");
    props.put("mail.smtp.starttls.enable", "true");

    Session session = Session.getInstance(props, new Authenticator() {
        @Override
        protected PasswordAuthentication getPasswordAuthentication() {
            return new PasswordAuthentication(from, password);
        }
    });

    try {
        Message message = new MimeMessage(session);
        message.setFrom(new InternetAddress(from));
        message.setRecipients(Message.RecipientType.TO, InternetAddress.parse(to));
        message.setSubject("HTML 郵件測試");

        // 設(shè)置 HTML 內(nèi)容
        String htmlContent = "<h1>歡迎使用 Java Mail</h1><p>這是一個 <b>HTML</b> 格式的郵件！</p>";
        message.setContent(htmlContent, "text/html;charset=UTF-8");

        Transport.send(message);
        System.out.println("HTML 郵件發(fā)送成功！");
    } catch (MessagingException e) {
        e.printStackTrace();
    }
}

public static void sendMailWithAttachment() {
    String host = "smtp.gmail.com";
    String from = "your_email@gmail.com";
    String password = "your_password";
    String to = "recipient_email@gmail.com";

    Properties props = new Properties();
    props.put("mail.smtp.host", host);
    props.put("mail.smtp.port", "587");
    props.put("mail.smtp.auth", "true");
    props.put("mail.smtp.starttls.enable", "true");

    Session session = Session.getInstance(props, new Authenticator() {
        @Override
        protected PasswordAuthentication getPasswordAuthentication() {
            return new PasswordAuthentication(from, password);
        }
    });

    try {
        Message message = new MimeMessage(session);
        message.setFrom(new InternetAddress(from));
        message.setRecipients(Message.RecipientType.TO, InternetAddress.parse(to));
        message.setSubject("帶附件的郵件測試");

        // 創(chuàng)建郵件正文
        MimeBodyPart textPart = new MimeBodyPart();
        textPart.setText("請查看附件！");

        // 創(chuàng)建附件部分
        MimeBodyPart attachmentPart = new MimeBodyPart();
        attachmentPart.attachFile("path/to/file.txt"); // 附件路徑

        // 合并正文和附件
        Multipart multipart = new MimeMultipart();
        multipart.addBodyPart(textPart);
        multipart.addBodyPart(attachmentPart);

        message.setContent(multipart);

        Transport.send(message);
        System.out.println("帶附件的郵件發(fā)送成功！");
    } catch (Exception e) {
        e.printStackTrace();
    }
}

props.put("mail.smtp.socketFactory.port", "465");
props.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
props.put("mail.smtp.port", "465");
props.put("mail.smtp.ssl.protocols", "TLSv1.2");