java开发邮件发送匿名

环境：jdk8,maven
需要的pom，高版本发送会验证spf，这个不会

        <dependency>            <groupId>javax.mail</groupId>            <artifactId>javax.mail-api</artifactId>            <version>1.5.6</version>        </dependency>

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<String, String> 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<next.size();i++) {                    String s = (String) next.get(i);                    smtp = (s).substring(s.lastIndexOf(' ')+1);                    break;                }            }        } catch (NamingException e) {            e.printStackTrace();        }        return smtp;    }}