校验邮箱是否存在

jar包
maven仓库地址

package com.majorel.framework.schedule.worker.utils;


import org.apache.commons.lang.ArrayUtils;
import org.apache.commons.lang.StringUtils;
import org.apache.commons.lang.builder.CompareToBuilder;
import org.xbill.DNS.Lookup;
import org.xbill.DNS.MXRecord;
import org.xbill.DNS.Record;
import org.xbill.DNS.Type;

import java.io.*;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;


public class MailValid {

    public static void main(String[] args) {
        System.out.println(valid("asfdfsafsaf@163.com", "jootmir.org"));
    }

    
    public static boolean valid(String toMail, String domain) {
        if (StringUtils.isBlank(toMail) || StringUtils.isBlank(domain)) return false;
        if (!StringUtils.contains(toMail, '@')) return false;
        String host = toMail.substring(toMail.indexOf('@') + 1);
        if (host.equals(domain)) return false;
        Socket socket = new Socket();
        try {
            // 查找mx记录
            Record[] mxRecords = new Lookup(host, Type.MX).run();
            if (ArrayUtils.isEmpty(mxRecords)) return false;
            // 邮件服务器地址
            String mxHost = ((MXRecord) mxRecords[0]).getTarget().toString();
            if (mxRecords.length > 1) { // 优先级排序
                List arrRecords = new ArrayList();
                Collections.addAll(arrRecords, mxRecords);
                Collections.sort(arrRecords, new Comparator() {

                    public int compare(Record o1, Record o2) {
                        return new CompareToBuilder().append(((MXRecord) o1).getPriority(), ((MXRecord) o2).getPriority()).toComparison();
                    }

                });
                mxHost = ((MXRecord) arrRecords.get(0)).getTarget().toString();
            }
            // 开始smtp
            socket.connect(new InetSocketAddress(mxHost, 25));
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(new BufferedInputStream(socket.getInputStream())));
            BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
            // 超时时间(毫秒)
            long timeout = 6000;
            // 睡眠时间片段(50毫秒)
            int sleepSect = 50;

            // 连接(服务器是否就绪)
            if (getResponseCode(timeout, sleepSect, bufferedReader) != 220) {
                return false;
            }

            // 握手
            bufferedWriter.write("HELO " + domain + "rn");
            bufferedWriter.flush();
            if (getResponseCode(timeout, sleepSect, bufferedReader) != 250) {
                return false;
            }
            // 身份
            bufferedWriter.write("MAIL FROM: rn");
            bufferedWriter.flush();
            if (getResponseCode(timeout, sleepSect, bufferedReader) != 250) {
                return false;
            }
            // 验证
            bufferedWriter.write("RCPT TO: <" + toMail + ">rn");
            bufferedWriter.flush();
            if (getResponseCode(timeout, sleepSect, bufferedReader) != 250) {
                return false;
            }
            // 断开
            bufferedWriter.write("QUITrn");
            bufferedWriter.flush();
            return true;
        } catch (NumberFormatException | IOException | InterruptedException e) {
            e.printStackTrace();
        } finally {
            try {
                socket.close();
            } catch (IOException ioe) {
                ioe.printStackTrace();
            }
        }
        return false;
    }


    private static int getResponseCode(long timeout, int sleepSect, BufferedReader bufferedReader) throws InterruptedException, NumberFormatException, IOException {
        int code = 0;
        for (long i = sleepSect; i < timeout; i += sleepSect) {
            Thread.sleep(sleepSect);
            if (bufferedReader.ready()) {
                String outline = bufferedReader.readLine();
                // FIXME 读完……
                while (bufferedReader.ready())
                    bufferedReader.readLine();
                code = Integer.parseInt(outline.substring(0, 3));
                break;
            }
        }
        return code;
    }
}