要用到commons-net-3.3.jar、dnsjava-2.1.7.jar包

大部分的國內常見郵箱都能準確驗證。

驗證頻率和數量多的話容易被封掉ip

package com.tieniu;
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.MXRecord;
import org.xbill.DNS.Record;
import org.xbill.DNS.Type;

public class CheckEmail {
	
	public static final String SENDER_EMAIL = "
 
[email protected]";//"[email protected]";
	public static final String SENDER_EMAIL_SERVER = SENDER_EMAIL.split("@")[1];//"domain.com";
	
	
	/**
	 * 
	 * @param email  The recipient's email address, it need to be validate if it is real exists or doesn't exists.
	 * @return True if email is real exists, false if not.
	 */
	public boolean checkEmailMethod(String email) {
		if (!email.matches("[\\w\\.\\-]
 
[email protected]([\\w\\-]+\\.)+[\\w\\-]+")) {
			System.err.println("Format error");
			return false;
		}

		String log = "";
		String host = "";
		String hostName = email.split("@")[1];
		Record[] result = null;
		SMTPClient client = new SMTPClient();
		client.setConnectTimeout(8000);  //設定連線超時時間,有些伺服器比較慢

		try {
			// 查詢MX記錄
			Lookup lookup = new Lookup(hostName, Type.MX);
			lookup.run();
			if (lookup.getResult() != Lookup.SUCCESSFUL) {
				log += "找不到MX記錄\n";
				return false;
			} else {
				result = lookup.getAnswers();
			}
/*
			 if(result.length > 1) { // 優先順序排序
	                List<Record> arrRecords = new ArrayList<Record>();
	                Collections.addAll(arrRecords, result);
	                Collections.sort(arrRecords, new Comparator<Record>() {
	                    
	                    public int compare(Record o1, Record o2) {
	                        return new CompareToBuilder().append(((MXRecord)o1).getPriority(), ((MXRecord)o2).getPriority()).toComparison();
	                    }
	                    
	                });
	                host = ((MXRecord)arrRecords.get(0)).getTarget().toString();
	            }
 * 
 */
			// 連線到郵箱伺服器
			
			for (int i = 0; i < result.length; i++) {
				System.out.println(result[i].getAdditionalName().toString());
				System.out.println(((MXRecord)result[i]).getPriority());
			}
			int count=0;  
//			String tempLog ="";
			for (int i = 0; i < result.length; i++) {
				log="";
				host = result[i].getAdditionalName().toString();
				try{
					client.connect(host);	//連線到接收郵箱地址的郵箱伺服器
				}catch(Exception e){		//捕捉連線超時的丟擲的異常
					count++;
					if(count>=result.length){	//如果由MX得到的result伺服器都連線不上，則認定email無效
						log +="Connect mail server timeout...\n";
						return false;
					}
				}
				
				if (!SMTPReply.isPositiveCompletion(client.getReplyCode())) {	//伺服器通訊不成功
					client.disconnect();
					continue;
				} else {
					log += "MX record about " + hostName + " exists.\n";
					log += "Connection succeeded to " + host + "\n";
					log += client.getReplyString();
					
					// HELO <$SENDER_EMAIL_SERVER>   //domain.com
					try{
						client.login(SENDER_EMAIL_SERVER);   //這一步可能會出現空指標異常
					}catch(Exception e){
						return false;
					}
					log += ">HELO "+SENDER_EMAIL_SERVER+"\n";
					log += "=" + client.getReplyString();
					
					client.setSender(SENDER_EMAIL);
					if(client.getReplyCode()!=250){		//為解決hotmail有的MX可能出現=550 OU-001 (SNT004-MC1F43) Unfortunately, messages from 116.246.2.245 weren't sent.
						client.disconnect();
						continue;							//把client.login 和client.setSender放在迴圈體內，這樣所有的如果某mx不行就換其他mx，但這樣會對無效的郵箱進行所有mx遍歷，耗時
					}
					log += ">MAIL FROM: <"+SENDER_EMAIL+">\n";
					log += "=" + client.getReplyString();
					// RCPT TO: <$email>
					try{
						client.addRecipient(email);
					}catch(Exception e){
						return false;
					}
					log += ">RCPT TO: <" + email + ">\n";
					log += "=" + client.getReplyString();
					
					//最後從收件郵箱伺服器返回true，說明伺服器中能夠找到此收件地址，郵箱有效
					if (250 == client.getReplyCode()) {
						return true;
					}
					client.disconnect();
					
				}
			}
//			log+=tempLog;
//			log += ">MAIL FROM: <"+SENDER_EMAIL+">\n";
//			log += "=" + client.getReplyString();
//			
//			// RCPT TO: <$email>
//			try{
//				client.addRecipient(email);
//			}catch(Exception e){
//				return false;
//			}
//			log += ">RCPT TO: <" + email + ">\n";
//			log += "=" + client.getReplyString();
//			
//			//最後從收件郵箱伺服器返回true，說明伺服器中能夠找到此收件地址，郵箱有效
//			if (250 == client.getReplyCode()) {
//				return true;
//			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			try {
				client.disconnect();
			} catch (IOException e) {
			}
			// print log
			System.out.println(log);
		}
		return false;
	}
	
	/**
	 * This method is more accurate than checkEmailMethod(String email);
	 * 
	 * @param email  The recipient's email address, it need to be validate if it is real exists or doesn't exists.
	 * @return True if email is real exists, false if not.
	 */
	public boolean checkEmail(String email){
		if(email.split("@")[1].equals("qq.com")){
			if( checkEmailMethod(email) && checkEmailMethod(email) && checkEmailMethod(email)){
				return true;
			}else{
				return false;
			}
		}
		return checkEmailMethod(email);
	}
	public static void main(String[] args) {
		CheckEmail ce = new CheckEmail();
		if(ce.checkEmail("
 
[email protected]")){
			System.out.println("true");
		}else{
			System.out.println("false");
		}
	}

}

其中還寫了一點開發過程中的相關文件，生成了該功能相應的jar包。也生成了dll，寫了供C#呼叫的使用方法。很簡單。

這裡附上附件的連結：http://pan.baidu.com/s/1jHpdDjC 密碼：wio6