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最新推荐文章于 2025-08-24 21:50:58 发布

pandajj

最新推荐文章于 2025-08-24 21:50:58 发布

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CC 4.0 BY-SA版权

文章标签： Apache .net

本文链接：https://blog.youkuaiyun.com/pandajj/article/details/83557312

本文介绍了一个Java程序，用于检查电子邮件地址的有效性。该程序通过正则表达式验证邮件格式，并利用DNS查找MX记录来确认邮件服务器的存在。此外，程序还使用SMTP协议与邮件服务器建立连接并发送测试命令。

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import java.io.IOException;

import org.apache.commons.net.smtp.SMTPClient;
import org.apache.commons.net.smtp.SMTPReply;
import org.xbill.DNS.Lookup;
import org.xbill.DNS.Record;
import org.xbill.DNS.Type;

public class CheckEmailObj {
	public static boolean checkEmail(String email) {
		if (!email.matches("[\\w\\.\\-]+@([\\w\\-]+\\.)+[\\w\\-]+")) {
			System.err.println("Format error");
			return false;
		}

		String log = "";
		String host = "";
		String hostName = email.split("@")[1];
		Record[] result = null;
		SMTPClient client = null;

		try {
			// find mx records
			Lookup lookup = new Lookup(hostName, Type.MX);
			lookup.run();
			if (lookup.getResult() != Lookup.SUCCESSFUL) {
				log += "Lookup error\n";
				return false;
			} else {
				result = lookup.getAnswers();
			}

			client = new SMTPClient();

			// telnet hostname 25
			for (int i = 0; i < result.length; i++) {
				host = result[i].getAdditionalName().toString();
				client.connect(host);
				if (!SMTPReply.isPositiveCompletion(client.getReplyCode())) {
					client.disconnect();
					continue;
				} else {
					log += "MX record about " + hostName + " exists.\n";
					log += "Connection succeeded to " + host + "\n";
					break;
				}
			}
			log += client.getReplyString();

			// HELO cyou-inc.com
			client.login("cyou-inc.com");
			log += ">HELO cyou-inc.com\n";
			log += "=" + client.getReplyString();

			// MAIL FROM: <zhaojinglun@cyou-inc.com>
			client.setSender("zhaojinglun@cyou-inc.com");
			log += ">MAIL FROM: <zhaojinglun@cyou-inc.com>\n";
			log += "=" + client.getReplyString();

			// RCPT TO: <$email>
			client.addRecipient(email);
			log += ">RCPT TO: <" + email + ">\n";
			log += "=" + client.getReplyString();

			// print log
			System.err.println(log);

			if (250 == client.getReplyCode()) {
				return true;
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			try {
				client.disconnect();
			} catch (IOException e) {
			}
		}
		return false;
	}

	public static void main(String[] args) {
		System.err.println("Outcome: "
				+ CheckEmailObj.checkEmail("pandajj0723@163.com"));
	}
}