环境：jdk8,maven

需要的pom，高版本发送会验证spf，这个不会

javax.mail

javax.mail-api

1.5.6

纯文本邮件内容发送

public class MailUtil {

private final static String FROM = "**@**.com";

public static void main(String[] args) {

String mail ="***@**.com";

String smtp = getSmtpByEmail(mail);

Properties props = new Properties();

props.put("mail.transport.protocol", "smtp");

props.put("mail.smtp.host", smtp);

props.put("mai.smtp.auth", "false");

Session session = Session.getInstance(props, null);

MimeMessage msg= new MimeMessage(session);

try {

msg.setFrom(FROM);

msg.setSubject("紧急通知","gb2312");

Multipart multipart = new MimeMultipart();

MimeBodyPart bodyPart = new MimeBodyPart();

bodyPart.setText("你的余额已不足", "gb2312");

multipart.addBodyPart(bodyPart);

msg.setContent(multipart);

msg.addHeader("X-Mailer", "Microsoft Outlook Express 6.00.2900.2869");

msg.setRecipient(MimeMessage.RecipientType.TO,new InternetAddress(mail));

Transport.send(msg);

System.out.println("send success");

} catch (MessagingException e) {

e.printStackTrace();

}

}

private static String getSmtpByEmail(String mail){

Hashtable hashtable = new Hashtable<>();

hashtable.put(Context.PROVIDER_URL, "dns://");

hashtable.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.dns.DnsContextFactory");

String domain = mail.substring(mail.lastIndexOf('@') + 1);

Attributes attrs = null;

String smtp=null;

try {

InitialDirContext dirContext = new InitialDirContext(hashtable);

attrs = dirContext.getAttributes(domain, new String[]{"MX"});

NamingEnumeration extends Attribute> attrsAll = attrs.getAll();

while(attrsAll.hasMore()) {

Attribute next = attrsAll.next();

for(int i=0;i

String s = (String) next.get(i);

smtp = (s).substring(s.lastIndexOf(' ')+1);

break;

}

}

} catch (NamingException e) {

e.printStackTrace();

}

return smtp;

}

}