<!-- https://mvnrepository.com/artifact/javax.mail/mail -->
 <dependency>
  <groupId>javax.mail</groupId>
  <artifactId>mail</artifactId>
  <version>1.4.7</version>
</dependency>

import java.io.File;
import java.io.UnsupportedEncodingException;
import java.util.Properties;
 
import javax.activation.DataHandler;
import javax.activation.FileDataSource;
import javax.mail.Authenticator;
import javax.mail.BodyPart;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.NoSuchProviderException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;
import javax.mail.internet.MimeUtility;
 
/**
 * 郵件發送工具類 <br/>
 * Author:楊杰超<br/>
 * Date:2020年1月9日 下午12:02:51 <br/>
 * Copyright (c) 2020, yangjiechao@dingtalk.com All Rights Reserved.<br/>
 *
 */
public class SendMail {
 
 /**
  * 想QQ郵箱發送郵件
  * 
  * @param formMail
  *   發送人郵箱地址
  * @param descMail
  *   接收人郵箱地址
  * @param subject
  *   郵箱主題
  * @param content
  *   郵箱內容
  * @param files
  *   附件列表
  * @param contentType
  *   內容格式
  * @param password
  *   SMTP密碼
  * @throws MessagingException
  * @throws UnsupportedEncodingException
  */
 public static void sendQQMail(String formMail, String descMail, String subject, String content, File[] files,
   String contentType, String password) throws MessagingException, UnsupportedEncodingException {
  Properties properties = new Properties();
  properties.setProperty("mail.smtp.host", "smtp.qq.com");
  properties.setProperty("mail.smtp.port", "465");
  properties.setProperty("mail.smtp.auth", "true");
  properties.setProperty("mail.debug", "true");
  properties.setProperty("mail.transport.protocol", "smtp");
  properties.setProperty("mail.smtp.ssl.enable", "true");
  Session session = Session.getInstance(properties, new Authenticator() {
   @Override
   protected PasswordAuthentication getPasswordAuthentication() {
    return new PasswordAuthentication(formMail, password);
   }
  });
  Message message = new MimeMessage(session);
  try {
   message.setFrom(new InternetAddress(formMail));
   message.setRecipient(Message.RecipientType.TO, new InternetAddress(descMail));
   message.setSubject(subject);
 
   // 是否存在附件
   if (null != files && files.length > 0) {
    MimeMultipart multipart = new MimeMultipart();
 
    BodyPart contentPart = new MimeBodyPart();
    contentPart.setContent(content, contentType);
    multipart.addBodyPart(contentPart);
 
    for (File file : files) {
     MimeBodyPart attachment = new MimeBodyPart();
     DataHandler dh3 = new DataHandler(new FileDataSource(file));
     attachment.setDataHandler(dh3);
     attachment.setFileName(MimeUtility.encodeText(dh3.getName()));
     multipart.addBodyPart(attachment);
    }
    multipart.setSubType("mixed");
 
    message.setContent(multipart);
    message.saveChanges();
   }
   // 普通
   else {
    message.setContent(content, contentType);
   }
 
   Transport transport = session.getTransport();
   transport.connect(formMail, password);
   Transport.send(message);
  } catch (UnsupportedEncodingException e) {
   throw e;
  } catch (NoSuchProviderException e) {
   throw e;
  } catch (MessagingException e) {
   throw e;
  }
 
 }
 
 public static void main(String[] args) throws MessagingException, UnsupportedEncodingException {
  // 由哪個郵箱發送
  String formMail = "********@qq.com";
  // QQ郵箱>設置>賬戶 開啟POP3/SMTP服務 查看smtp密碼
  String smtpPassword = "****************";
 
  // 發送人郵箱地址
  String descMail = "470947852@qq.com";
  String contentType = "text/html;charset=UTF-8";
 
  String subject = "測試郵件發送，含附件";
  String content = "test send mail, 這里是中文";
  File[] files = new File[2];
  files[0] = new File("C:/test_1.xls");
  files[1] = new File("C:/test_2.xls");
 
  SendMail.sendQQMail(formMail, descMail, subject, content, files, contentType, smtpPassword);
 }
}