// DNS服务器，看看本机的DNS配置
        String dns = "dns://192.168.0.1";
        String email = "xxx@msn.com";
        if(args.length>0)
         email = args[0];
        String domain = email.substring(email.indexOf('@')+1);
        Hashtable env = new Hashtable();
        env.put(Context.INITIAL_CONTEXT_FACTORY,
          "com.sun.jndi.dns.DnsContextFactory");
        env.put(Context.PROVIDER_URL, dns);
        DirContext ctx = new InitialDirContext(env);
        Attributes attr = ctx.getAttributes(domain, new String[]{"MX" });
        NamingEnumeration servers = attr.getAll();
        // 列出所有邮件服务器：
        while(servers.hasMore()) {
         Attribute hosts = (Attribute)servers.next();
         for(int i=0;i<hosts.size();i++){
          String host = (String)hosts.get(i);
          host = host.substring(host.indexOf(' ')+1);
          System.out.print("Send mail to " + host + " ...");
          sendMail(host, email);
          System.out.println("OK");
         }
        }