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

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+---
+title: >-
+  Java mail IMAP list example - List all the email addresses in an IMAP mailbox
+  | alvinalexander.com
+updated: 2024-06-03 19:13:23Z
+created: 2024-06-03 19:13:23Z
+source: >-
+  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.
+
+## 
+
+![Ezoic](../_resources/ezoicbwa_3db014528c7e452480e81686ac4ece27.png "ezoic")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);
+  }
+
+}
+
+## 
+
+![Ezoic](../_resources/ezoicbwa_3db014528c7e452480e81686ac4ece27.png "ezoic")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.
+
+![Ezoic](../_resources/ezoicbwa_3db014528c7e452480e81686ac4ece27.png "ezoic")
+
+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.