(Java) Read IMAP Email Headers

Call FetchHeaders to download only the email headers.

Note: This example requires Chilkat v11.0.0 or greater.

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import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    boolean success = false;

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    CkImap imap = new CkImap();

    // Connect to an IMAP server.
    // Use TLS
    imap.put_Ssl(true);
    imap.put_Port(993);
    success = imap.Connect("imap.example.com");
    if (success == false) {
        System.out.println(imap.lastErrorText());
        return;
        }

    // Login
    success = imap.Login("****","****");
    if (success == false) {
        System.out.println(imap.lastErrorText());
        return;
        }

    // Select an IMAP mailbox
    success = imap.SelectMailbox("Inbox");
    if (success == false) {
        System.out.println(imap.lastErrorText());
        return;
        }

    // Get the message IDs of all the emails in the mailbox
    // We can choose to fetch UIDs or sequence numbers.
    boolean fetchUids = true;
    CkMessageSet messageSet = new CkMessageSet();
    success = imap.QueryMbx("ALL",fetchUids,messageSet);
    if (success == false) {
        System.out.println(imap.lastErrorText());
        return;
        }

    // When downloading headers, each email object contains
    // (obviously) the headers, but the body will be missing.
    // Also, attachments will not be included.  However, it is
    // possible to get information about the attachments
    // as well as the complete size of the email.
    CkEmailBundle bundle = new CkEmailBundle();
    boolean headersOnly = true;
    success = imap.FetchMsgSet(headersOnly,messageSet,bundle);
    if (success == false) {
        System.out.println(imap.lastErrorText());
        return;
        }

    // Loop over the email objects and display information
    // about each:
    CkEmail email = new CkEmail();
    String name;
    String addr;
    int i = 0;
    int j = 0;
    while (i < bundle.get_MessageCount()) {
        bundle.EmailAt(i,email);

        // Display the From and Subject
        System.out.println(email.ck_from());
        System.out.println(email.subject());

        // Display the recipients:
        j = 0;
        while (j < email.get_NumTo()) {
            System.out.println("TO: " + email.getToName(j) + ", " + email.getToAddr(j));
            j = j+1;
            }

        j = 0;
        while (j < email.get_NumCC()) {
            System.out.println("CC: " + email.getCcName(j) + ", " + email.getCcAddr(j));
            j = j+1;
            }

        // Show the total size of the email, including body and attachments:
        System.out.println(email.get_Size());

        // When a full email is downloaded, we would use the
        // email.NumAttachments property in conjunction with the
        // email.GetMailAttach* methods.
        // However, when an email object contains only the header,
        // we need to access the attachment info differently:
        int numAttach = imap.GetMailNumAttach(email);
        j = 0;
        while (j < numAttach) {
            System.out.println(imap.getMailAttachFilename(email,j));
            int attachSize = imap.GetMailAttachSize(email,j);
            System.out.println("    size = " + attachSize + " bytes");
            j = j+1;
            }

        System.out.println("--");
        }

    // Disconnect from the IMAP server.
    success = imap.Disconnect();
  }
}