1.开通POP和IMAP

2.引入pom

<dependency><groupId>javax.mail</groupId><artifactId>mail</artifactId><version>1.4.7</version>
</dependency>

3.逻辑

String host = "smtp.qiye.aliyun.com";
String port = "465";
String username = "xxxxxx@dingtalk.com"; // 钉钉发送者邮箱
String password = "xxxxxx"; // 发送者邮箱账号
String toEmail = "xxxxx@dingtalk.com"; // 钉钉接收者邮箱
String subject = "邮件标题"try {Properties props = new Properties();props.setProperty("mail.smtp.host", host);props.setProperty("mail.smtp.port", port);props.setProperty("mail.smtp.socketFactory.class","javax.net.ssl.SSLSocketFactory");props.setProperty("mail.smtp.socketFactory.fallback", "false");// 启用调试//props.setProperty("mail.debug", "true");props.setProperty("mail.smtp.socketFactory.port", port);props.setProperty("mail.smtp.auth", "true");// 建立邮件会话Session session = Session.getDefaultInstance(props, new Authenticator() {@Overrideprotected PasswordAuthentication getPasswordAuthentication() {return new PasswordAuthentication(username, password);}});// 建立邮件对象MimeMessage message = new MimeMessage(session);message.setFrom(new InternetAddress(username));message.setRecipients(Message.RecipientType.TO, toEmail);message.setSubject(subject);MimeMultipart multipart = new MimeMultipart();BodyPart contentPart = new MimeBodyPart();// 邮件正文contentPart.setContent(content, "text/html;charset=utf-8");multipart.addBodyPart(contentPart);// 附件MimeBodyPart attachmentBodyPart = new MimeBodyPart();// 读取本地文件，如果是前端传过来的MultipartFile文件，需要将MultipartFile转为file，再通过下面的方式：// File file = MultipartFileToFile(multipartFile);// DataSource source = new FileDataSource(file);// attachmentBodyPart.setDataHandler(new DataHandler(source));DataHandler dataHandler = new DataHandler(new FileDataSource("E:\\soft\\test.doc");attachmentBodyPart.setDataHandler(dataHandler);attachmentBodyPart.setFileName("test.doc");multipart.addBodyPart(attachmentBodyPart);// 设置邮件整体内容message.setContent(multipart);Transport.send(message);
} catch (Exception e) {e.printStackTrace();
}

4.直接添加前端传过来的MultipartFile

.....
MimeMultipart multipart = new MimeMultipart();
BodyPart contentPart = new MimeBodyPart();
// 邮件正文
contentPart.setContent(content, "text/html;charset=utf-8");
multipart.addBodyPart(contentPart);
// 附件--这里改下
MimeBodyPart attachmentBodyPart = new MimeBodyPart();
File file = MultipartFileToFile(multipartFile);
DataSource source = new FileDataSource(file);
attachmentBodyPart.setDataHandler(new DataHandler(source));
attachmentBodyPart.setFileName(file.getName());
multipart.addBodyPart(attachmentBodyPart);
// 设置邮件整体内容
message.setContent(multipart);
Transport.send(message);
.....

5.添加多个附件

MimeMultipart multipart = new MimeMultipart();
BodyPart contentPart = new MimeBodyPart();
// 邮件正文
contentPart.setContent(content, "text/html;charset=utf-8");
multipart.addBodyPart(contentPart);
// 附件--这里改下
for (MultipartFile multipartFile : files){MimeBodyPart attachmentBodyPart = new MimeBodyPart();File file = MultipartFileToFile(multipartFile);DataSource source = new FileDataSource(file);//添加附件的内容attachmentBodyPart.setDataHandler(new DataHandler(source));//添加附件的标题attachmentBodyPart.setFileName(file.getName());multipart.addBodyPart(filePart);
}
// 设置邮件整体内容
message.setContent(multipart);
Transport.send(message);

6.给多个邮箱发邮件

String tos = "a1@dingtalk.com,a2@dingtalk.com,a3@dingtalk.com";
String[] toList = to.split(",");
Address[] addresses = new Address[toList.length];
for (int i = 0; i < toList.length; i++) {addresses[i] = new InternetAddress(toList[i]);
}
message.setRecipients(Message.RecipientType.TO, addresses);