javax.email是否支持在正文中添加电子邮件签名？

import javax.mail.*;
import javax.mail.internet.*;

public class EmailExample {
    public static void main(String[] args) {
        String host = "smtp.example.com";
        String username = "yourusername";
        String password = "yourpassword";
        String fromAddress = "from@example.com";
        String toAddress = "to@example.com";

        Properties properties = System.getProperties();
        properties.setProperty("mail.smtp.host", host);
        properties.setProperty("mail.smtp.auth", "true");

        Session session = Session.getDefaultInstance(properties, new Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(username, password);
            }
        });

        try {
            MimeMessage message = new MimeMessage(session);
            message.setFrom(new InternetAddress(fromAddress));
            message.addRecipient(Message.RecipientType.TO, new InternetAddress(toAddress));
            message.setSubject("Example Email");

            // 创建邮件正文内容
            MimeBodyPart textPart = new MimeBodyPart();
            textPart.setText("This is the email body.");

            // 创建电子邮件签名内容
            MimeBodyPart signaturePart = new MimeBodyPart();
            signaturePart.setText("Best regards,\nJohn Doe");

            // 创建复合MIME类型容器
            MimeMultipart multipart = new MimeMultipart();
            multipart.addBodyPart(textPart);
            multipart.addBodyPart(signaturePart);

            // 将复合MIME类型容器设置为邮件内容
            message.setContent(multipart);

            // 发送邮件
            Transport.send(message);
            System.out.println("Email sent successfully.");
        } catch (MessagingException e) {
            e.printStackTrace();
        }
    }
}