JavaMail reading recent unread mails using IMAP

问题

I have a requirement to retrieve unread mails from Gmail. I am using Java Mail API. By default, this API retrieves mails from the oldest to newest. But I need to retrieve recent mails first. Is it possible? Thanks in advance.

回答1:

Here is example. Do not forget to add javax.mail in your classpath.

import javax.mail.*;
import javax.mail.search.FlagTerm;
import java.util.*;

public class GmailFetch {

  public static void main( String[] args ) throws Exception {

    Session session = Session.getDefaultInstance(new Properties( ));
    Store store = session.getStore("imaps");
    store.connect("imap.googlemail.com", 993, "username@gmail.com", "password");
    Folder inbox = store.getFolder( "INBOX" );
    inbox.open( Folder.READ_ONLY );

    // Fetch unseen messages from inbox folder
    Message[] messages = inbox.search(
        new FlagTerm(new Flags(Flags.Flag.SEEN), false));

    // Sort messages from recent to oldest
    Arrays.sort( messages, ( m1, m2 ) -> {
      try {
        return m2.getSentDate().compareTo( m1.getSentDate() );
      } catch ( MessagingException e ) {
        throw new RuntimeException( e );
      }
    } );

    for ( Message message : messages ) {
      System.out.println( 
          "sendDate: " + message.getSentDate()
          + " subject:" + message.getSubject() );
    }
  }
}

回答2:

Make sure to use the IMAP protocol, as it supports for flagging.

Do following changes to your code:

replace inbox.open( Folder.READ_ONLY ); by inbox.open( Folder.READ_WRITE );
Then after reading the message, set the flag like so:
```
message.setFlag(Flags.Flag.SEEN, true);
```

Full example:

    import javax.mail.*;
    import javax.mail.search.FlagTerm;
    import java.util.*;

    public class GmailFetch {

      public static void main( String[] args ) throws Exception {

        Session session = Session.getDefaultInstance(new Properties( ));
        Store store = session.getStore("imaps");
        store.connect("imap.googlemail.com", 993, "username@gmail.com", "password");
        Folder inbox = store.getFolder( "INBOX" );
        inbox.open( Folder.READ_WRITE );

        // Fetch unseen messages from inbox folder
        Message[] messages = inbox.search(
            new FlagTerm(new Flags(Flags.Flag.SEEN), false));

        // Sort messages from recent to oldest
        Arrays.sort( messages, ( m1, m2 ) -> {
          try {
            return m2.getSentDate().compareTo( m1.getSentDate() );
          } catch ( MessagingException e ) {
            throw new RuntimeException( e );
          }
        } );

        for ( Message message : messages ) {
          System.out.println( 
              "sendDate: " + message.getSentDate()
              + " subject:" + message.getSubject() );
              message.setFlag(Flags.Flag.SEEN, true);
        }
      }
    }

回答3:

JavaMail gives you an array of Message objects. The messages are in the order received. If you want to look at the most recently received messages first, go through the array in the reverse order. If you want to look at the most recently sent messages first, you'll need to sort the array, as described in the other answer.

回答4:

I think this might help to access read/unread/recent mails change your variables according to your needs.

// search for all "unseen" messages

Flags seen = new Flags(Flags.Flag.SEEN);// try changing this SEEN to RECENT 

// set it true or false for seen & unseen mail

FlagTerm unseenFlagTerm = new FlagTerm(seen, false)
Message messages[] = inbox.search(unseenFlagTerm);

来源：https://stackoverflow.com/questions/28689099/javamail-reading-recent-unread-mails-using-imap

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java

javamail

imap