✔ Mail versenden via SMTP

[Fabio Hellmann]

Hallo Community,

ich tüftel bereits den ganzen Tag an meiner Mailsender Klasse. Ich versuche aus meinem Programm via SMTP eine Mail zu versenden.

Folgendes irritiert mich aber: Wenn ich meine Mailsender-Klasse als JUnit-Test laufen lasse, wird die Mail verschickt. TOP!

Wenn ich die Mailsender-Klasse aber in mein Hauptprogramm einbinde (exakt genau so wie im JUnit-Test), bekomm ich folgende Exception, wenn ich vorher nicht überprüfe, ob der Mailserver erreichbar ist.

<javax.mail.MessagingException: Could not connect to SMTP host: localhost, port: 25;
  nested exception is:
	java.net.ConnectException: Connection refused: connect>
javax.mail.MessagingException: Could not connect to SMTP host: localhost, port: 25;
  nested exception is:
	java.net.ConnectException: Connection refused: connect
	at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1282)
	at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:370)
	at javax.mail.Service.connect(Service.java:275)
	at javax.mail.Service.connect(Service.java:156)
	at javax.mail.Service.connect(Service.java:105)
	at javax.mail.Transport.send0(Transport.java:168)
	at javax.mail.Transport.send(Transport.java:98)
	at de.util.MailUtils.createAndSend(MailUtils.java:113)
Caused by: java.net.ConnectException: Connection refused: connect
	at java.net.PlainSocketImpl.socketConnect(Native Method)
	at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
	at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
	at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
	at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
	at java.net.Socket.connect(Socket.java:529)
	at java.net.Socket.connect(Socket.java:478)
	at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:232)
	at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:189)
	at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1250)
	... 12 more

Zeile 113 entspricht im Code Zeile 82.

Wenn ich nun überprüfe, ob der Mailserver verfügbar ist, bekomm ich folgende Exception:

<javax.mail.NoSuchProviderException: Invalid protocol: null>
javax.mail.NoSuchProviderException: Invalid protocol: null
	at javax.mail.Session.getProvider(Session.java:431)
	at javax.mail.Session.getStore(Session.java:530)
	at javax.mail.Session.getStore(Session.java:510)
	at javax.mail.Session.getStore(Session.java:496)
	at de.util.MailUtils.isReachable(MailUtils.java:140)

Zeile 140 entspricht im Code 109.

Hier ist noch mein Code den ich verwende:

	/**	 */
	public static final String SMTP = "smtp";
	/**	 */
	public static final String MAIL_SMTP_HOST = "mail.smtp.host";
	/**	 */
	public static final String MAIL_SMTP_PORT = "mail.smtp.port";
	/**	 */
	public static final String MAIL_TRANSPORT_PROTOCOL = "mail.transport.protocol";
	/**	 */
	public static final int DEFAULT_SMTP_PORT = 25;

	private MailUtils() {
	}

	/**
	 * @param mailProps 
	 * @param from
	 * @param recipient
	 * @param subject
	 * @param content
	 * @param attachment
	 * @throws MessagingException 
	 */
	public static void createAndSend(Properties mailProps, String from, String[] recipient,
			String subject, String content, File[] attachment) 
	throws MessagingException {
		Session session = Session.getDefaultInstance(mailProps);
		session.setDebug(true);
		session.setDebugOut(System.out);
		
		Message message = new MimeMessage(session);

		// ----------------------------------------------------------------------
		// Meta-Data
		// ----------------------------------------------------------------------

		// From
		message.setFrom(new InternetAddress(from));

		// Recipients
		InternetAddress[] recipients = new InternetAddress[recipient.length];
		for(int i = 0; i < recipient.length; i++) {
			recipients[i] = new InternetAddress(recipient[i]);
		}
		message.setRecipients(Message.RecipientType.TO, recipients);

		// Subjectline
		message.setSubject(subject);

		// ----------------------------------------------------------------------
		// Content
		// ----------------------------------------------------------------------
		MimeMultipart mimeMultipart = new MimeMultipart();

		MimeBodyPart contentBody = new MimeBodyPart();
		contentBody.setText(content);
		contentBody.setDisposition(MimeBodyPart.INLINE);
		mimeMultipart.addBodyPart(contentBody);

		// ----------------------------------------------------------------------
		// Attachments
		// ----------------------------------------------------------------------
		for(File file : attachment) {
			if(file != null && file.exists() && file.canRead()) {
				MimeBodyPart attachmentBody = new MimeBodyPart();
				attachmentBody.setDataHandler(new DataHandler(new FileDataSource(file)));
				attachmentBody.setFileName(file.getName());
				attachmentBody.setDisposition(MimeBodyPart.ATTACHMENT);
				
				mimeMultipart.addBodyPart(attachmentBody);	
			}
		}

		// ---
		// save
		message.setContent(mimeMultipart);
		message.saveChanges();

		// send
		Transport.send(message);
	}
	
	/**
	 * @param smtpHost
	 * @param port 
	 * @return the Properties with the Transportprotocol and SMTP-Host
	 */
	public static Properties createSmtpMailProperties(String smtpHost, int port) {
		Properties mailProps = new Properties();
		mailProps.put(MAIL_TRANSPORT_PROTOCOL, SMTP);
		mailProps.put(MAIL_SMTP_HOST, smtpHost);
		mailProps.put(MAIL_SMTP_PORT, String.valueOf(port));
		return mailProps;
	}
	
	/**
	 * @param host
	 * @param port
	 * @return true if the MailRelay is reachable.
	 */
	public static boolean isReachable(String host, int port) {
		Properties properties = createSmtpMailProperties(host, port);
		Session s = Session.getDefaultInstance(properties);
		try {
			Transport transport = s.getTransport();
			transport.connect();
			return true;
		} catch(MessagingException e) {
			e.printStackTrace();
		}
		return false;
	}

Die Debugausgabe hat folgendes ergeben:

DEBUG: setDebug: JavaMail version 1.4ea
DEBUG: getProvider() returning javax.mail.Provider[TRANSPORT,smtp,com.sun.mail.smtp.SMTPTransport,Sun Microsystems, Inc]
DEBUG SMTP: useEhlo true, useAuth false
DEBUG SMTP: trying to connect to host "localhost", port 25, isSSL false

Ich hoffe, dass mir bei dem Problem jemand auf die Sprünge helfen kann.

Gruß

Fabio

 

[Fabio Hellmann]

Problem gelöst!
Es lag an folgender Ursache: Da in dem Programm verschiedene SMTP-Verbindungen sind, darf man im Code nicht schreiben

Session.getDetaulfIntsance(properties, null)

sondern

Session.getInstance(properties, null)

Dann werden nicht die globalen SMTP-Einstellungen verwendet, sondern die Properties, die übergeben werden.

Gruß

Fabio