Javamail: Mailbox always downloads the same email

Question

I’m downloading the emails from Gmail, and storing in the database those that are important to my client’s system.

Only the problem is when I use the code below, it always returns me the same emails, staying in duplicity.

Someone’s been through it?

Code:

try {
    System.out.println("asdasdasd");
    // create properties field
    Properties properties = new Properties();

    properties.put("mail.pop3.host", host);
    properties.put("mail.pop3.port", "995");
    properties.put("mail.pop3.starttls.enable", "true");
    Session emailSession = Session.getDefaultInstance(properties);

    // create the POP3 store object and connect with the pop server
    Store store = emailSession.getStore("pop3s");

    store.connect(host, user, password);

    // create the folder object and open it
    Folder emailFolder = store.getFolder("INBOX");
    emailFolder.open(Folder.READ_ONLY);

    Message[] messages = emailFolder.getMessages();
    System.out.println("messages.length---" + messages.length);

    for (int i = 0, n = messages.length; i < n; i++) {
        Message message = messages[i];
        System.out.println("---------------------------------");
        System.out.println("Email Number " + (i + 1));
        System.out.println("Subject: " + message.getSubject());
        System.out.println("From: " + message.getFrom()[0]);
        System.out.println("Text: " + message.getContent().toString());
        System.out.println(message.getLineCount());

    }

    // close the store and folder objects
    emailFolder.close(false);
    store.close();

} catch (NoSuchProviderException e) {
    e.printStackTrace();
} catch (MessagingException e) {
    e.printStackTrace();
} catch (Exception e) {
    e.printStackTrace();
}

Answer 1

When you perform Message[] messages = emailFolder.getMessages(); it returns ALL Folder messages, which in your case is INBOX, which is why it always brings the same messages.

You can solve the problem by applying a filter (Not read for example) in the message rescue, deleting the messages from the printer or moving to another folder, for example:

Applying a filter to redeem messages:
Alter Message[] messages = emailFolder.getMessages(); for:

// O filtro aqui são as mensagens não visualizadas ainda
FlagTerm ft = new FlagTerm(new Flags(Flags.Flag.SEEN), false);
Message messages[] = inbox.search(ft);

Deleting messages from Folder

Folder emailFolder = store.getFolder("INBOX");
emailFolder.open(Folder.READ_WRITE);

Message[] messages = emailFolder.getMessages();
System.out.println("messages.length---" + messages.length);

for (int i = 0, n = messages.length; i < n; i++) {
    Message message = messages[i];
    System.out.println("---------------------------------");
    System.out.println("Email Number " + (i + 1));
    System.out.println("Subject: " + message.getSubject());
    System.out.println("From: " + message.getFrom()[0]);
    System.out.println("Text: " + message.getContent().toString());
    System.out.println(message.getLineCount());
}

// close the store and folder objects
emailFolder.setFlags(messages, new Flags(Flags.Flag.DELETED), true);
emailFolder.close(true);
store.close();

Moving to another folder:

Folder emailFolder = store.getFolder("INBOX");
Folder folderDestino = store.getFolder("PASTA DE DESTINO");
emailFolder.open(Folder.READ_WRITE);
folderDestino.open(Folder.READ_WRITE);

Message[] messages = emailFolder.getMessages();
System.out.println("messages.length---" + messages.length);

for (int i = 0, n = messages.length; i < n; i++) {
    Message message = messages[i];
    System.out.println("---------------------------------");
    System.out.println("Email Number " + (i + 1));
    System.out.println("Subject: " + message.getSubject());
    System.out.println("From: " + message.getFrom()[0]);
    System.out.println("Text: " + message.getContent().toString());
    System.out.println(message.getLineCount());
}

// close the store and folder objects
emailFolder.copyMessages(messages, folderDestino);
emailFolder.setFlags(messages, new Flags(Flags.Flag.DELETED), true);

emailFolder.close(true);
folderDestino.close(true);
store.close();

There is still the possibility to determine the beginning and end of the messages that will be captured in the method getMessages but I believe this solution is very bad.