thpeetz-notes/Posteingang/Java mail IMAP list example - List all the email a.md

title, updated, created, source

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Java mail IMAP list example - List all the email addresses in an IMAP mailbox | alvinalexander.com	2024-06-03 19:13:23Z	2024-06-03 19:13:23Z	https://alvinalexander.com/blog/post/java/i-need-get-all-of-my-email-addresses-out-of-imap-mailbox/

By Alvin Alexander. Last updated: March 12, 2018

Java Mail (JavaMail) IMAP FAQ: Can you show me how to get a list of all the email addresses in an IMAP mailbox using the Java Mail API (JavaMail API)?

Sure. Here's the source code for a Java mail (JavaMail) program that extracts all of the "from" fields out of a specified mailbox. This works for both POP3 and IMAP mailboxes.

Before going to the code, note the cool use of a TreeSet (java.util.TreeSet) in this example. Based on our offline discussion, you mentioned that you really want is this:

1. Only the unique email addresses, and
2. The addresses sorted alphabetically.

Therefore, a TreeSet is a great data type for this purpose.

My JavaMail IMAP email address list program

With no further ado, here is the source code for my JavaMail email address list/extractor:

import javax.mail.*; import javax.mail.internet.*; import java.util.*; import java.io.*;

/** * My JavaMail email address extractor. * A JavaMail API example. * @author alvin alexander, alvinalexander.com. */ public class AddressExtractor {

public static void main(String[] args) { Properties props = new Properties();

String host      = args\[0\];
String username  = args\[1\];
String password  = args\[2\];
//String provider  = "pop3";
String provider  = "imap";

try
{
  //Connect to the server
  Session session = Session.getDefaultInstance(props, null);
  Store store     = session.getStore(provider);
  store.connect(host, username, password);

  //open the inbox folder
  Folder inbox = store.getFolder("INBOX");
  inbox.open(Folder.READ_ONLY);

  // get a list of javamail messages as an array of messages
  Message\[\] messages = inbox.getMessages();

  TreeSet treeSet = new TreeSet();

  for(int i = 0; i < messages.length; i++)
  {
    String from = getFrom(messages\[i\]);
    if ( from!=null)
    {
      from = removeQuotes(from);
      treeSet.add(from);
    }
  }

  Iterator it = treeSet.iterator();
  while ( it.hasNext() )
  {
    System.out.println("from: " + it.next());
  }

  //close the inbox folder but do not
  //remove the messages from the server
  inbox.close(false);
  store.close();
}
catch (NoSuchProviderException nspe)
{
  System.err.println("invalid provider name");
}
catch (MessagingException me)
{
  System.err.println("messaging exception");
  me.printStackTrace();
}

}

private static String getFrom(Message javaMailMessage) throws MessagingException { String from = ""; Address a[] = javaMailMessage.getFrom(); if ( a==null ) return null; for ( int i=0; i<a.length; i++ ) { Address address = a[i]; from = from + address.toString(); }

return from;

}

private static String removeQuotes(String stringToModify) { int indexOfFind = stringToModify.indexOf(stringToModify); if ( indexOfFind < 0 ) return stringToModify;

StringBuffer oldStringBuffer = new StringBuffer(stringToModify);
StringBuffer newStringBuffer = new StringBuffer();
for ( int i=0, length=oldStringBuffer.length(); i<length; i++ )
{
  char c = oldStringBuffer.charAt(i);
  if ( c == '"' || c == '\\'' )
  {
    // do nothing
  }
  else
  {
    newStringBuffer.append(c);
  }

}
return new String(newStringBuffer);

}

}

JavaMail IMAP list example - Discussion

Besides the TreeSet and JavaMail stuff going on, the removeQuotes() method may also be of interest to you. This method removes single- and double-quotes from the email address. During testing, I ran into situations where one email address was *almost* the same as another address, except for cases where one email address had a name embedded in single-quotes, and the other address had no quotes or double-quotes. Because both addresses are technically the same for what I needed, I added this method to strip out all quotes.

Note that you will also need the following JavaMail API jar files for this Java email extractor class to work:

1. mail.jar
2. activation.jar

These jar files can be downloaded from Sun's web site. Just look for the JavaMail API on their site for instructions on obtaining these Jar files.