В этой статье будет подробно рассмотрен пример отправки и приема писем и реализация почтового клиента написанного на java.. Вам понадобится javamail API для компиляции этого примера. Вы можете скачать его здесь.
Пример содержит следующие файлы/классы:
- EmailClient: основной класс для клиентского приложения электронной почты
- ConnectDialog: этот класс отображает диалоговое окно для ввода электронной почты сервер подключения.
- MessagesTableModel: этот класс управляет электронной таблицей данных.
- MessageDialog: этот класс отображает диалоговое окно используется для создания сообщения.
- DownloadingDialog: этот класс отображает простое диалоговое окно с инструкциями пользователя, о том что сообщения загружаются.
Код достаточно большой но в нем имеются комментарии по описанию email client java. Содержание классов описаны ниже:
import java.awt.*;
import java.awt.event.*;
import java.net.*;
import java.util.*;
import javax.mail.*;
import javax.mail.internet.*;
import javax.swing.*;
import javax.swing.event.*;
// The E-mail Client.
public class EmailClient extends JFrame {
// Message table's data model.
private MessagesTableModel tableModel;
// Table listing messages.
private JTable table;
// This the text area for displaying messages.
private JTextArea messageTextArea;
/* This is the split panel that holds the messages
table and the message view panel. */
private JSplitPane splitPane;
// These are the buttons for managing the selected message.
private JButton replyButton, forwardButton, deleteButton;
// Currently selected message in table.
private Message selectedMessage;
// Flag for whether or not a message is being deleted.
private boolean deleting;
// This is the JavaMail session.
private Session session;
// Constructor for E-mail Client.
public EmailClient() {
// Set application title.
setTitle("E-mail Client");
// Set window size.
setSize(640, 480);
// Handle window closing events.
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
actionExit();
}
});
// Setup file menu.
JMenuBar menuBar = new JMenuBar();
JMenu fileMenu = new JMenu("File");
fileMenu.setMnemonic(KeyEvent.VK_F);
JMenuItem fileExitMenuItem = new JMenuItem("Exit",
KeyEvent.VK_X);
fileExitMenuItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
actionExit();
}
});
fileMenu.add(fileExitMenuItem);
menuBar.add(fileMenu);
setJMenuBar(menuBar);
// Setup buttons panel.
JPanel buttonPanel = new JPanel();
JButton newButton = new JButton("New Message");
newButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
actionNew();
}
});
buttonPanel.add(newButton);
// Setup messages table.
tableModel = new MessagesTableModel();
table = new JTable(tableModel);
table.getSelectionModel().addListSelectionListener(new
ListSelectionListener() {
public void valueChanged(ListSelectionEvent e) {
tableSelectionChanged();
}
});
// Allow only one row at a time to be selected.
table.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
// Setup E-mails panel.
JPanel emailsPanel = new JPanel();
emailsPanel.setBorder(
BorderFactory.createTitledBorder("E-mails"));
messageTextArea = new JTextArea();
messageTextArea.setEditable(false);
splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT,
new JScrollPane(table), new JScrollPane(messageTextArea));
emailsPanel.setLayout(new BorderLayout());
emailsPanel.add(splitPane, BorderLayout.CENTER);
// Setup buttons panel 2.
JPanel buttonPanel2 = new JPanel();
replyButton = new JButton("Reply");
replyButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
actionReply();
}
});
replyButton.setEnabled(false);
buttonPanel2.add(replyButton);
forwardButton = new JButton("Forward");
forwardButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
actionForward();
}
});
forwardButton.setEnabled(false);
buttonPanel2.add(forwardButton);
deleteButton = new JButton("Delete");
deleteButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
actionDelete();
}
});
deleteButton.setEnabled(false);
buttonPanel2.add(deleteButton);
// Add panels to display.
getContentPane().setLayout(new BorderLayout());
getContentPane().add(buttonPanel, BorderLayout.NORTH);
getContentPane().add(emailsPanel, BorderLayout.CENTER);
getContentPane().add(buttonPanel2, BorderLayout.SOUTH);
}
// Exit this program.
private void actionExit() {
System.exit(0);
}
// Create a new message.
private void actionNew() {
sendMessage(MessageDialog.NEW, null);
}
// Called when table row selection changes.
private void tableSelectionChanged() {
/* If not in the middle of deleting a message, set
the selected message and display it. */
if (!deleting) {
selectedMessage =
tableModel.getMessage(table.getSelectedRow());
showSelectedMessage();
updateButtons();
}
}
// Reply to a message.
private void actionReply() {
sendMessage(MessageDialog.REPLY, selectedMessage);
}
// Forward a message.
private void actionForward() {
sendMessage(MessageDialog.FORWARD, selectedMessage);
}
// Delete the selected message.
private void actionDelete() {
deleting = true;
try {
// Delete message from server.
selectedMessage.setFlag(Flags.Flag.DELETED, true);
Folder folder = selectedMessage.getFolder();
folder.close(true);
folder.open(Folder.READ_WRITE);
} catch (Exception e) {
showError("Unable to delete message.", false);
}
// Delete message from table.
tableModel.deleteMessage(table.getSelectedRow());
// Update GUI.
messageTextArea.setText("");
deleting = false;
selectedMessage = null;
updateButtons();
}
// Send the specified message.
private void sendMessage(int type, Message message) {
// Display message dialog to get message values.
MessageDialog dialog;
try {
dialog = new MessageDialog(this, type, message);
if (!dialog.display()) {
// Return if dialog was cancelled.
return;
}
} catch (Exception e) {
showError("Unable to send message.", false);
return;
}
try {
// Create a new message with values from dialog.
Message newMessage = new MimeMessage(session);
newMessage.setFrom(new InternetAddress(dialog.getFrom()));
newMessage.setRecipient(Message.RecipientType.TO,
new InternetAddress(dialog.getTo()));
newMessage.setSubject(dialog.getSubject());
newMessage.setSentDate(new Date());
newMessage.setText(dialog.getContent());
// Send new message.
Transport.send(newMessage);
} catch (Exception e) {
showError("Unable to send message.", false);
}
}
// Show the selected message in the content panel.
private void showSelectedMessage() {
// Show hour glass cursor while message is loaded.
setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR));
try {
messageTextArea.setText(
getMessageContent(selectedMessage));
messageTextArea.setCaretPosition(0);
} catch (Exception e) {
showError("Unabled to load message.", false);
} finally {
// Return to default cursor.
setCursor(Cursor.getDefaultCursor());
}
}
/* Update each button's state based off of whether or not
there is a message currently selected in the table. */
private void updateButtons() {
if (selectedMessage != null) {
replyButton.setEnabled(true);
forwardButton.setEnabled(true);
deleteButton.setEnabled(true);
} else {
replyButton.setEnabled(false);
forwardButton.setEnabled(false);
deleteButton.setEnabled(false);
}
}
// Show the application window on the screen.
public void show() {
super.show();
// Update the split panel to be divided 50/50.
splitPane.setDividerLocation(.5);
}
// Connect to e-mail server.
public void connect() {
// Display connect dialog.
ConnectDialog dialog = new ConnectDialog(this);
dialog.show();
// Build connection URL from connect dialog settings.
StringBuffer connectionUrl = new StringBuffer();
connectionUrl.append(dialog.getType() + "://");
connectionUrl.append(dialog.getUsername() + ":");
connectionUrl.append(dialog.getPassword() + "@");
connectionUrl.append(dialog.getServer() + "/");
/* Display dialog stating that messages are
currently being downloaded from server. */
final DownloadingDialog downloadingDialog =
new DownloadingDialog(this);
SwingUtilities.invokeLater(new Runnable() {
public void run() {
downloadingDialog.show();
}
});
// Establish JavaMail session and connect to server.
Store store = null;
try {
// Initialize JavaMail session with SMTP server.
Properties props = new Properties();
props.put("mail.smtp.host", dialog.getSmtpServer());
session = Session.getDefaultInstance(props, null);
// Connect to e-mail server.
URLName urln = new URLName(connectionUrl.toString());
store = session.getStore(urln);
store.connect();
} catch (Exception e) {
// Close the downloading dialog.
downloadingDialog.dispose();
// Show error dialog.
showError("Unable to connect.", true);
}
// Download message headers from server.
try {
// Open main "INBOX" folder.
Folder folder = store.getFolder("INBOX");
folder.open(Folder.READ_WRITE);
// Get folder's list of messages.
Message[] messages = folder.getMessages();
// Retrieve message headers for each message in folder.
FetchProfile profile = new FetchProfile();
profile.add(FetchProfile.Item.ENVELOPE);
folder.fetch(messages, profile);
// Put messages in table.
tableModel.setMessages(messages);
} catch (Exception e) {
// Close the downloading dialog.
downloadingDialog.dispose();
// Show error dialog.
showError("Unable to download messages.", true);
}
// Close the downloading dialog.
downloadingDialog.dispose();
}
// Show error dialog and exit afterwards if necessary.
private void showError(String message, boolean exit) {
JOptionPane.showMessageDialog(this, message, "Error",
JOptionPane.ERROR_MESSAGE);
if (exit)
System.exit(0);
}
// Get a message's content.
public static String getMessageContent(Message message)
throws Exception {
Object content = message.getContent();
if (content instanceof Multipart) {
StringBuffer messageContent = new StringBuffer();
Multipart multipart = (Multipart) content;
for (int i = 0; i < multipart.getCount(); i++) {
Part part = (Part) multipart.getBodyPart(i);
if (part.isMimeType("text/plain")) {
messageContent.append(part.getContent().toString());
}
}
return messageContent.toString();
} else {
return content.toString();
}
}
// Run the E-mail Client.
public static void main(String[] args) {
EmailClient client = new EmailClient();
client.show();
// Display connect dialog.
client.connect();
}
}
ConnectDialog:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/* This class displays a dialog for entering e-mail
server connection settings. */
public class ConnectDialog extends JDialog {
// These are the e-mail server types.
private static final String[] TYPES = {"pop3", "imap"};
// Combo box for e-mail server types.
private JComboBox typeComboBox;
// Server, username and SMTP server text fields.
private JTextField serverTextField, usernameTextField;
private JTextField smtpServerTextField;
// Password text field.
private JPasswordField passwordField;
// Constructor for dialog.
public ConnectDialog(Frame parent) {
// Call super constructor, specifying that dialog is modal.
super(parent, true);
// Set dialog title.
setTitle("Connect");
// Handle closing events.
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
actionCancel();
}
});
// Setup settings panel.
JPanel settingsPanel = new JPanel();
settingsPanel.setBorder(
BorderFactory.createTitledBorder("Connection Settings"));
GridBagConstraints constraints;
GridBagLayout layout = new GridBagLayout();
settingsPanel.setLayout(layout);
JLabel typeLabel = new JLabel("Type:");
constraints = new GridBagConstraints();
constraints.anchor = GridBagConstraints.EAST;
constraints.insets = new Insets(5, 5, 0, 0);
layout.setConstraints(typeLabel, constraints);
settingsPanel.add(typeLabel);
typeComboBox = new JComboBox(TYPES);
constraints = new GridBagConstraints();
constraints.anchor = GridBagConstraints.WEST;
constraints.gridwidth = GridBagConstraints.REMAINDER;
constraints.insets = new Insets(5, 5, 0, 5);
constraints.weightx = 1.0D;
layout.setConstraints(typeComboBox, constraints);
settingsPanel.add(typeComboBox);
JLabel serverLabel = new JLabel("Server:");
constraints = new GridBagConstraints();
constraints.anchor = GridBagConstraints.EAST;
constraints.insets = new Insets(5, 5, 0, 0);
layout.setConstraints(serverLabel, constraints);
settingsPanel.add(serverLabel);
serverTextField = new JTextField(25);
constraints = new GridBagConstraints();
constraints.gridwidth = GridBagConstraints.REMAINDER;
constraints.insets = new Insets(5, 5, 0, 5);
constraints.weightx = 1.0D;
layout.setConstraints(serverTextField, constraints);
settingsPanel.add(serverTextField);
JLabel usernameLabel = new JLabel("Username:");
constraints = new GridBagConstraints();
constraints.anchor = GridBagConstraints.EAST;
constraints.insets = new Insets(5, 5, 0, 0);
layout.setConstraints(usernameLabel, constraints);
settingsPanel.add(usernameLabel);
usernameTextField = new JTextField();
constraints = new GridBagConstraints();
constraints.anchor = GridBagConstraints.WEST;
constraints.fill = GridBagConstraints.HORIZONTAL;
constraints.gridwidth = GridBagConstraints.REMAINDER;
constraints.insets = new Insets(5, 5, 0, 5);
constraints.weightx = 1.0D;
layout.setConstraints(usernameTextField, constraints);
settingsPanel.add(usernameTextField);
JLabel passwordLabel = new JLabel("Password:");
constraints = new GridBagConstraints();
constraints.anchor = GridBagConstraints.EAST;
constraints.insets = new Insets(5, 5, 5, 0);
layout.setConstraints(passwordLabel, constraints);
settingsPanel.add(passwordLabel);
passwordField = new JPasswordField();
constraints = new GridBagConstraints();
constraints.anchor = GridBagConstraints.WEST;
constraints.fill = GridBagConstraints.HORIZONTAL;
constraints.gridwidth = GridBagConstraints.REMAINDER;
constraints.insets = new Insets(5, 5, 5, 5);
constraints.weightx = 1.0D;
layout.setConstraints(passwordField, constraints);
settingsPanel.add(passwordField);
JLabel smtpServerLabel = new JLabel("SMTP Server:");
constraints = new GridBagConstraints();
constraints.anchor = GridBagConstraints.EAST;
constraints.insets = new Insets(5, 5, 5, 0);
layout.setConstraints(smtpServerLabel, constraints);
settingsPanel.add(smtpServerLabel);
smtpServerTextField = new JTextField(25);
constraints = new GridBagConstraints();
constraints.gridwidth = GridBagConstraints.REMAINDER;
constraints.insets = new Insets(5, 5, 5, 5);
constraints.weightx = 1.0D;
layout.setConstraints(smtpServerTextField, constraints);
settingsPanel.add(smtpServerTextField);
// Setup buttons panel.
JPanel buttonsPanel = new JPanel();
JButton connectButton = new JButton("Connect");
connectButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
actionConnect();
}
});
buttonsPanel.add(connectButton);
JButton cancelButton = new JButton("Cancel");
cancelButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
actionCancel();
}
});
buttonsPanel.add(cancelButton);
// Add panels to display.
getContentPane().setLayout(new BorderLayout());
getContentPane().add(settingsPanel, BorderLayout.CENTER);
getContentPane().add(buttonsPanel, BorderLayout.SOUTH);
// Size dialog to components.
pack();
// Center dialog over application.
setLocationRelativeTo(parent);
}
// Validate connection settings and close dialog.
private void actionConnect() {
if (serverTextField.getText().trim().length() < 1
|| usernameTextField.getText().trim().length() < 1
|| passwordField.getPassword().length < 1
|| smtpServerTextField.getText().trim().length() < 1) {
JOptionPane.showMessageDialog(this,
"One or more settings is missing.",
"Missing Setting(s)", JOptionPane.ERROR_MESSAGE);
return;
}
// Close dialog.
dispose();
}
// Cancel connecting and exit program.
private void actionCancel() {
System.exit(0);
}
// Get e-mail server type.
public String getType() {
return (String) typeComboBox.getSelectedItem();
}
// Get e-mail server.
public String getServer() {
return serverTextField.getText();
}
// Get e-mail username.
public String getUsername() {
return usernameTextField.getText();
}
// Get e-mail password.
public String getPassword() {
return new String(passwordField.getPassword());
}
// Get e-mail SMTP server.
public String getSmtpServer() {
return smtpServerTextField.getText();
}
}
MessagesTableModel:
import java.util.*;
import javax.mail.*;
import javax.swing.*;
import javax.swing.table.*;
// This class manages the e-mail table's data.
public class MessagesTableModel extends AbstractTableModel {
// These are the names for the table's columns.
private static final String[] columnNames = {"Sender",
"Subject", "Date"};
// The table's list of messages.
private ArrayList messageList = new ArrayList();
// Sets the table's list of messages.
public void setMessages(Message[] messages) {
for (int i = messages.length - 1; i >= 0; i--) {
messageList.add(messages[i]);
}
// Fire table data change notification to table.
fireTableDataChanged();
}
// Get a message for the specified row.
public Message getMessage(int row) {
return (Message) messageList.get(row);
}
// Remove a message from the list.
public void deleteMessage(int row) {
messageList.remove(row);
// Fire table row deletion notification to table.
fireTableRowsDeleted(row, row);
}
// Get table's column count.
public int getColumnCount() {
return columnNames.length;
}
// Get a column's name.
public String getColumnName(int col) {
return columnNames[col];
}
// Get table's row count.
public int getRowCount() {
return messageList.size();
}
// Get value for a specific row and column combination.
public Object getValueAt(int row, int col) {
try {
Message message = (Message) messageList.get(row);
switch (col) {
case 0: // Sender
Address[] senders = message.getFrom();
if (senders != null || senders.length > 0) {
return senders[0].toString();
} else {
return "[none]";
}
case 1: // Subject
String subject = message.getSubject();
if (subject != null && subject.length() > 0) {
return subject;
} else {
return "[none]";
}
case 2: // Date
Date date = message.getSentDate();
if (date != null) {
return date.toString();
} else {
return "[none]";
}
}
} catch (Exception e) {
// Fail silently.
return "";
}
return "";
}
}
MessageDialog:
import java.awt.*;
import java.awt.event.*;
import javax.mail.*;
import javax.swing.*;
// This class displays the dialog used for creating messages.
public class MessageDialog extends JDialog {
// Dialog message identifiers.
public static final int NEW = 0;
public static final int REPLY = 1;
public static final int FORWARD = 2;
// Message from, to and subject text fields.
private JTextField fromTextField, toTextField;
private JTextField subjectTextField;
// Message content text area.
private JTextArea contentTextArea;
// Flag specifying whether or not dialog was cancelled.
private boolean cancelled;
// Constructor for dialog.
public MessageDialog(Frame parent, int type, Message message)
throws Exception {
// Call super constructor, specifying that dialog is modal.
super(parent, true);
/* Set dialog title and get message's "to", "subject"
and "content" values based on message type. */
String to = "", subject = "", content = "";
switch (type) {
// Reply message.
case REPLY:
setTitle("Reply To Message");
// Get message "to" value
Address[] senders = message.getFrom();
if (senders != null || senders.length > 0) {
to = senders[0].toString();
}
to = message.getFrom()[0].toString();
// Get message subject.
subject = message.getSubject();
if (subject != null && subject.length() > 0) {
subject = "RE: " + subject;
} else {
subject = "RE:";
}
// Get message content and add "REPLIED TO" notation.
content = "\n----------------- " +
"REPLIED TO MESSAGE" +
" -----------------\n" +
EmailClient.getMessageContent(message);
break;
// Forward message.
case FORWARD:
setTitle("Forward Message");
// Get message subject.
subject = message.getSubject();
if (subject != null && subject.length() > 0) {
subject = "FWD: " + subject;
} else {
subject = "FWD:";
}
// Get message content and add "FORWARDED" notation.
content = "\n----------------- " +
"FORWARDED MESSAGE" +
" -----------------\n" +
EmailClient.getMessageContent(message);
break;
// New message.
default:
setTitle("New Message");
}
// Handle closing events.
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
actionCancel();
}
});
// Setup fields panel.
JPanel fieldsPanel = new JPanel();
GridBagConstraints constraints;
GridBagLayout layout = new GridBagLayout();
fieldsPanel.setLayout(layout);
JLabel fromLabel = new JLabel("From:");
constraints = new GridBagConstraints();
constraints.anchor = GridBagConstraints.EAST;
constraints.insets = new Insets(5, 5, 0, 0);
layout.setConstraints(fromLabel, constraints);
fieldsPanel.add(fromLabel);
fromTextField = new JTextField();
constraints = new GridBagConstraints();
constraints.fill = GridBagConstraints.HORIZONTAL;
constraints.gridwidth = GridBagConstraints.REMAINDER;
constraints.insets = new Insets(5, 5, 0, 0);
layout.setConstraints(fromTextField, constraints);
fieldsPanel.add(fromTextField);
JLabel toLabel = new JLabel("To:");
constraints = new GridBagConstraints();
constraints.anchor = GridBagConstraints.EAST;
constraints.insets = new Insets(5, 5, 0, 0);
layout.setConstraints(toLabel, constraints);
fieldsPanel.add(toLabel);
toTextField = new JTextField(to);
constraints = new GridBagConstraints();
constraints.fill = GridBagConstraints.HORIZONTAL;
constraints.gridwidth = GridBagConstraints.REMAINDER;
constraints.insets = new Insets(5, 5, 0, 0);
constraints.weightx = 1.0D;
layout.setConstraints(toTextField, constraints);
fieldsPanel.add(toTextField);
JLabel subjectLabel = new JLabel("Subject:");
constraints = new GridBagConstraints();
constraints.insets = new Insets(5, 5, 5, 0);
layout.setConstraints(subjectLabel, constraints);
fieldsPanel.add(subjectLabel);
subjectTextField = new JTextField(subject);
constraints = new GridBagConstraints();
constraints.fill = GridBagConstraints.HORIZONTAL;
constraints.gridwidth = GridBagConstraints.REMAINDER;
constraints.insets = new Insets(5, 5, 5, 0);
layout.setConstraints(subjectTextField, constraints);
fieldsPanel.add(subjectTextField);
// Setup content panel.
JScrollPane contentPanel = new JScrollPane();
contentTextArea = new JTextArea(content, 10, 50);
contentPanel.setViewportView(contentTextArea);
// Setup buttons panel.
JPanel buttonsPanel = new JPanel();
JButton sendButton = new JButton("Send");
sendButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
actionSend();
}
});
buttonsPanel.add(sendButton);
JButton cancelButton = new JButton("Cancel");
cancelButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
actionCancel();
}
});
buttonsPanel.add(cancelButton);
// Add panels to display.
getContentPane().setLayout(new BorderLayout());
getContentPane().add(fieldsPanel, BorderLayout.NORTH);
getContentPane().add(contentPanel, BorderLayout.CENTER);
getContentPane().add(buttonsPanel, BorderLayout.SOUTH);
// Size dialog to components.
pack();
// Center dialog over application.
setLocationRelativeTo(parent);
}
// Validate message fields and close dialog.
private void actionSend() {
if (fromTextField.getText().trim().length() < 1
|| toTextField.getText().trim().length() < 1
|| subjectTextField.getText().trim().length() < 1
|| contentTextArea.getText().trim().length() < 1) {
JOptionPane.showMessageDialog(this,
"One or more fields is missing.",
"Missing Field(s)", JOptionPane.ERROR_MESSAGE);
return;
}
// Close dialog.
dispose();
}
// Cancel creating this message and close dialog.
private void actionCancel() {
cancelled = true;
// Close dialog.
dispose();
}
// Show dialog.
public boolean display() {
show();
// Return whether or not display was successful.
return !cancelled;
}
// Get message's "From" field value.
public String getFrom() {
return fromTextField.getText();
}
// Get message's "To" field value.
public String getTo() {
return toTextField.getText();
}
// Get message's "Subject" field value.
public String getSubject() {
return subjectTextField.getText();
}
// Get message's "content" field value.
public String getContent() {
return contentTextArea.getText();
}
}
DownloadingDialog:
import java.awt.*;
import javax.swing.*;
/* This class displays a simple dialog instructing the user
that messages are being downloaded. */
public class DownloadingDialog extends JDialog {
// Constructor for dialog.
public DownloadingDialog(Frame parent) {
// Call super constructor, specifying that dialog is modal.
super(parent, true);
// Set dialog title.
setTitle("E-mail Client");
// Instruct window not to close when the "X" is clicked.
setDefaultCloseOperation(DO_NOTHING_ON_CLOSE);
// Put a message with a nice border in this dialog.
JPanel contentPane = new JPanel();
contentPane.setBorder(
BorderFactory.createEmptyBorder(5, 5, 5, 5));
contentPane.add(new JLabel("Downloading messages..."));
setContentPane(contentPane);
// Size dialog to components.
pack();
// Center dialog over application.
setLocationRelativeTo(parent);
}
}