JAVA验证邮箱是否有效

JAVA验证邮箱是否有效，没有使用外部jar包，用的都是jdk的包

public static boolean checkEmail1(String email) {
		if (!email.matches("[\w\.\-]+@([\w\-]+\.)+[\w\-]+")) {
			return false;
		}
		String log = "";
		String host = "";
		String hostName = email.split("@")[1];// 去掉@后面的
		//输出邮箱域名
		System.out.println("hostName:" + hostName);
		Record[] result = null;
		SMTPClient client = new SMTPClient();
		//设置超时时间
		client.setConnectTimeout(8000);
		try {
			// 查找DN的SMX记录
			org.xbill.DNS.Lookup lookup = new org.xbill.DNS.Lookup(hostName, Type.MX);
			lookup.run();
			if (lookup.getResult() != org.xbill.DNS.Lookup.SUCCESSFUL) {
				System.out.println("找不到MX记录");
				return false;
			} else {
				result = lookup.getAnswers();
				//循环打印DNS服务器
				for (int i = 0; i < result.length; i++) {
					System.out.println(result[i].getAdditionalName().toString());
				}
			}
			// 循环连接到邮箱DNS服务器
			for (int i = 0; i < result.length; i++) {
				host = result[i].getAdditionalName().toString();
				//IP地址
				//System.out.println("ip:"+InetAddress.getByName(host).getHostAddress());
				int count=0;
				try {
					client.connect(host);//捕获超时异常
				} catch (Exception e) {
					count++;
					//
					if(count>=result.length){
						return false;
					}
				}
				if (!SMTPReply.isPositiveCompletion(client.getReplyCode())) {
					client.disconnect();
					continue;
				} else {
					log += "邮箱mx记录" + hostName + "存在";
					log += "成功连接到" + host;
					break;
				}
			}
			client.login("163.com");
			client.setSender("www.linuxidc.com@linuxidc.com");// 发件人
			log += "=" + client.getReplyString();
			client.addRecipient(email);//发送邮件测试邮箱地址是否存在
			log += "n";
			log += "=" + client.getReplyString();
			System.out.println(log+"  code"+client.getReplyCode());
			if (250 == client.getReplyCode()) {
				return true;
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			try {
				client.disconnect();
			} catch (IOException e) {
			} 

		}
		return false;

	}