JavaxMail将PDF作为文件发送

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

public class SendEmail {
   public static void main(String [] args) {
      // 设置邮件服务器
      String host = "smtp.example.com";
      String username = "yourusername";
      String password = "yourpassword";
      
      // 设置发件人和收件人
      String from = "sender@example.com";
      String to = "recipient@example.com";
      
      // 创建邮件会话
      Properties props = System.getProperties();
      props.setProperty("mail.smtp.host", host);
      props.setProperty("mail.smtp.auth", "true");
      Session session = Session.getDefaultInstance(props, new Authenticator() {
          protected PasswordAuthentication getPasswordAuthentication() {
              return new PasswordAuthentication(username, password);
          }
      });
      
      try {
         // 创建邮件消息
         MimeMessage message = new MimeMessage(session);
         message.setFrom(new InternetAddress(from));
         message.addRecipient(Message.RecipientType.TO, new InternetAddress(to));
         message.setSubject("Sending a PDF file");
         
         // 创建一个Multipart对象
         Multipart multipart = new MimeMultipart();
         
         // 创建邮件正文
         MimeBodyPart textPart = new MimeBodyPart();
         textPart.setText("This is the body of the email.");
         multipart.addBodyPart(textPart);
         
         // 创建邮件附件
         MimeBodyPart attachmentPart = new MimeBodyPart();
         attachmentPart.attachFile("path/to/pdf/file.pdf");
         multipart.addBodyPart(attachmentPart);
         
         // 设置邮件内容
         message.setContent(multipart);
         
         // 发送邮件
         Transport.send(message);
         System.out.println("Email sent successfully!");
      } catch (Exception ex) {
         ex.printStackTrace();
      }
   }
}