a. Search the Java Web site for information on how to use a JTextArea. Write an

Question

a. Search the Java Web site for information on how to use a JTextArea. Write an
application for the WebBuy Company that allows a user to compose the three
parts of a complete e-mail message: the “To:”, “Subject:”, and “Message:” text.
The “To:” and “Subject:” text areas should provide a single line for data entry.
The “Message:” area should allow multiple lines of input and be able to scroll if
necessary to accommodate a long message. The user clicks a button to send the
e-mail message. When the message is complete and the Send button is clicked,
the application should display “Mail has been sent!” on a new line in the message
area. Save the file as JEMail.java.
b. Modify the JEMail application to include a Clear button that the user can
click at any time to clear the “To:”, “Subject:”, and “Message:” fields. Save the file
as JEMail2.java.

Explanation / Answer

a)

Please do follow the code :

Setting for the SMTP server is stored in smtp.properties file with the following content:

mail.smtp.host=smtp.gmail.com
mail.smtp.port=587
mail.user=abc.net@gmail.com
mail.password=secret
mail.smtp.starttls.enable=true
mail.smtp.auth=true

This is a typical SMTP setting for a GMail account. You should change the mail.user and mail.password according to your account. The e-mail address here will be displayed as sender in the out-going e-mail message. Put this file under the application’s directory.
The application needs JavaMail API to work, so download latest version of JavaMail here. And put the javax.mail.jar file under your project’s classpath.

The application consists of four main classes:

EmailUtility.java: implements a function for sending an e-mail message including attachments. See the article Send e-mail with attachment in Java for more details.

ConfigUtility.java: implements two functions for reading and writing SMTP settings from/to the smtp.properties file as described above.

SettingsDialog.java: implements a user interface that allows the user to update SMTP settings.

JEmail.java: is the main entry of the application, it builds the main user interface that displays e-mail sending form and connects all the above pieces together. To allow the user to add a file as attachment, this class uses the JFilePicker class which is introduced in this article: File picker component in Swing.

1. Coding the EmailUtility class :

This class is very straightforward with only one static, generic function sendEmail() which will be used by the JEmail class. Here’s its code:

import java.io.File;
import java.io.IOException;
import java.util.Date;
import java.util.Properties;

import javax.mail.Authenticator;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.AddressException;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;

/**
* A utility class that sends an e-mail message with attachments.
* @author www.codejava.net
*
*/
public class EmailUtility {
public static void sendEmail(Properties smtpProperties, String toAddress,
String subject, String message, File[] attachFiles)
throws AddressException, MessagingException, IOException {

final String userName = smtpProperties.getProperty("mail.user");
final String password = smtpProperties.getProperty("mail.password");

// creates a new session with an authenticator
Authenticator auth = new Authenticator() {
public PasswordAuthentication getPasswordAuthentication() {
return new PasswordAuthentication(userName, password);
}
};
Session session = Session.getInstance(smtpProperties, auth);

// creates a new e-mail message
Message msg = new MimeMessage(session);

msg.setFrom(new InternetAddress(userName));
InternetAddress[] toAddresses = { new InternetAddress(toAddress) };
msg.setRecipients(Message.RecipientType.TO, toAddresses);
msg.setSubject(subject);
msg.setSentDate(new Date());

// creates message part
MimeBodyPart messageBodyPart = new MimeBodyPart();
messageBodyPart.setContent(message, "text/html");

// creates multi-part
Multipart multipart = new MimeMultipart();
multipart.addBodyPart(messageBodyPart);

// adds attachments
if (attachFiles != null && attachFiles.length > 0) {
for (File aFile : attachFiles) {
MimeBodyPart attachPart = new MimeBodyPart();

try {
attachPart.attachFile(aFile);
} catch (IOException ex) {
throw ex;
}

multipart.addBodyPart(attachPart);
}
}

// sets the multi-part as e-mail's content
msg.setContent(multipart);

// sends the e-mail
Transport.send(msg);

}
}

2. Coding the ConfigUtility class

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Properties;

/**
* A utility class that reads/saves SMTP settings from/to a properties file.
* @author www.codejava.net
*
*/
public class ConfigUtility {
private File configFile = new File("smtp.properties");
private Properties configProps;

public Properties loadProperties() throws IOException {
Properties defaultProps = new Properties();
// sets default properties
defaultProps.setProperty("mail.smtp.host", "smtp.gmail.com");
defaultProps.setProperty("mail.smtp.port", "587");
defaultProps.setProperty("mail.user", "tom@gmail.com");
defaultProps.setProperty("mail.password", "secret");
defaultProps.setProperty("mail.smtp.starttls.enable", "true");
defaultProps.setProperty("mail.smtp.auth", "true");

configProps = new Properties(defaultProps);

// loads properties from file
if (configFile.exists()) {
InputStream inputStream = new FileInputStream(configFile);
configProps.load(inputStream);
inputStream.close();
}

return configProps;
}

public void saveProperties(String host, String port, String user, String pass) throws IOException {
configProps.setProperty("mail.smtp.host", host);
configProps.setProperty("mail.smtp.port", port);
configProps.setProperty("mail.user", user);
configProps.setProperty("mail.password", pass);
configProps.setProperty("mail.smtp.starttls.enable", "true");
configProps.setProperty("mail.smtp.auth", "true");

OutputStream outputStream = new FileOutputStream(configFile);
configProps.store(outputStream, "host setttings");
outputStream.close();
}
}

This class will be used by the JEmail and SettingsDialog classes

3. Coding the SettingsDialog class :

The structure of this class is as follows:

public class SettingsDialog extends JDialog {
private ConfigUtility configUtil;

// GUI components declaration

public SettingsDialog(JFrame parent, ConfigUtility configUtil) {

setupForm();

loadSettings();

}

private void setupForm() { }

private void loadSettings() { }

private void buttonSaveActionPerformed(ActionEvent event) { }
}

And following is its full code:

import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;
import java.util.Properties;

import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JTextField;

/**
* Displays a setting form that allows configuring SMTP settings.
* @author www.codejava.net
*
*/
public class SettingsDialog extends JDialog {

private ConfigUtility configUtil;

private JLabel labelHost = new JLabel("Host name: ");
private JLabel labelPort = new JLabel("Port number: ");
private JLabel labelUser = new JLabel("Username: ");
private JLabel labelPass = new JLabel("Password: ");

private JTextField textHost = new JTextField(20);
private JTextField textPort = new JTextField(20);
private JTextField textUser = new JTextField(20);
private JTextField textPass = new JTextField(20);

private JButton buttonSave = new JButton("Save");

public SettingsDialog(JFrame parent, ConfigUtility configUtil) {
super(parent, "SMTP Settings", true);
this.configUtil = configUtil;

setupForm();

loadSettings();

pack();
setLocationRelativeTo(null);
}

private void setupForm() {
setLayout(new GridBagLayout());
GridBagConstraints constraints = new GridBagConstraints();
constraints.gridx = 0;
constraints.gridy = 0;
constraints.insets = new Insets(10, 10, 5, 10);
constraints.anchor = GridBagConstraints.WEST;

add(labelHost, constraints);

constraints.gridx = 1;
add(textHost, constraints);

constraints.gridy = 1;
constraints.gridx = 0;
add(labelPort, constraints);

constraints.gridx = 1;
add(textPort, constraints);

constraints.gridy = 2;
constraints.gridx = 0;
add(labelUser, constraints);

constraints.gridx = 1;
add(textUser, constraints);

constraints.gridy = 3;
constraints.gridx = 0;
add(labelPass, constraints);

constraints.gridx = 1;
add(textPass, constraints);

constraints.gridy = 4;
constraints.gridx = 0;
constraints.gridwidth = 2;
constraints.anchor = GridBagConstraints.CENTER;
add(buttonSave, constraints);

buttonSave.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent event) {
buttonSaveActionPerformed(event);
}
});
}

private void loadSettings() {
Properties configProps = null;
try {
configProps = configUtil.loadProperties();
} catch (IOException ex) {
JOptionPane.showMessageDialog(this,
"Error reading settings: " + ex.getMessage(),
"Error", JOptionPane.ERROR_MESSAGE);
}

textHost.setText(configProps.getProperty("mail.smtp.host"));
textPort.setText(configProps.getProperty("mail.smtp.port"));
textUser.setText(configProps.getProperty("mail.user"));
textPass.setText(configProps.getProperty("mail.password"));
}

private void buttonSaveActionPerformed(ActionEvent event) {
try {
configUtil.saveProperties(textHost.getText(),
textPort.getText(),
textUser.getText(),
textPass.getText());
JOptionPane.showMessageDialog(SettingsDialog.this,
"Properties were saved successfully!");
dispose();
} catch (IOException ex) {
JOptionPane.showMessageDialog(this,
"Error saving properties file: " + ex.getMessage(),
"Error", JOptionPane.ERROR_MESSAGE);
}
}
}

4. Coding the JEmail class :

The structure of this class is as follows:

public class JEmail extends JFrame {
private ConfigUtility configUtil = new ConfigUtility();

// GUI components declaration

public JEmail() {

setupMenu();
setupForm();

}

private void setupMenu() { }

private void setupForm() { }

private void buttonSendActionPerformed(ActionEvent event) { }

private boolean validateFields() { }

public static void main(String[] args) { }
}

And following is its full code:

import java.awt.Font;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.util.Properties;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JOptionPane;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;

import net.codejava.swing.JFilePicker;

/**
* A Swing application that allows sending e-mail messages from a SMTP server.
* @author www.codejava.net
*
*/
public class JEmail extends JFrame {
private ConfigUtility configUtil = new ConfigUtility();

private JMenuBar menuBar = new JMenuBar();
private JMenu menuFile = new JMenu("File");
private JMenuItem menuItemSetting = new JMenuItem("Settings..");

private JLabel labelTo = new JLabel("To: ");
private JLabel labelSubject = new JLabel("Subject: ");

private JTextField fieldTo = new JTextField(30);
private JTextField fieldSubject = new JTextField(30);

private JButton buttonSend = new JButton("SEND");

private JFilePicker filePicker = new JFilePicker("Attached", "Attach File...");

private JTextArea textAreaMessage = new JTextArea(10, 30);

private GridBagConstraints constraints = new GridBagConstraints();

public JEmail() {
super("Swing E-mail Sender Program");

// set up layout
setLayout(new GridBagLayout());
constraints.anchor = GridBagConstraints.WEST;
constraints.insets = new Insets(5, 5, 5, 5);

setupMenu();
setupForm();

pack();
setLocationRelativeTo(null); // center on screen
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}

private void setupMenu() {
menuItemSetting.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent event) {
SettingsDialog dialog = new SettingsDialog(JEmail.this, configUtil);
dialog.setVisible(true);
}
});

menuFile.add(menuItemSetting);
menuBar.add(menuFile);
setJMenuBar(menuBar);
}

private void setupForm() {
constraints.gridx = 0;
constraints.gridy = 0;
add(labelTo, constraints);

constraints.gridx = 1;
constraints.fill = GridBagConstraints.HORIZONTAL;
add(fieldTo, constraints);

constraints.gridx = 0;
constraints.gridy = 1;
add(labelSubject, constraints);

constraints.gridx = 1;
constraints.fill = GridBagConstraints.HORIZONTAL;
add(fieldSubject, constraints);

constraints.gridx = 2;
constraints.gridy = 0;
constraints.gridheight = 2;
constraints.fill = GridBagConstraints.BOTH;
buttonSend.setFont(new Font("Arial", Font.BOLD, 16));
add(buttonSend, constraints);

buttonSend.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent event) {
buttonSendActionPerformed(event);
}
});

constraints.gridx = 0;
constraints.gridy = 2;
constraints.gridheight = 1;
constraints.gridwidth = 3;
filePicker.setMode(JFilePicker.MODE_OPEN);
add(filePicker, constraints);

constraints.gridy = 3;
constraints.weightx = 1.0;
constraints.weighty = 1.0;

add(new JScrollPane(textAreaMessage), constraints);
}

private void buttonSendActionPerformed(ActionEvent event) {
if (!validateFields()) {
return;
}

String toAddress = fieldTo.getText();
String subject = fieldSubject.getText();
String message = textAreaMessage.getText();

File[] attachFiles = null;

if (!filePicker.getSelectedFilePath().equals("")) {
File selectedFile = new File(filePicker.getSelectedFilePath());
attachFiles = new File[] {selectedFile};
}

try {
Properties smtpProperties = configUtil.loadProperties();
EmailUtility.sendEmail(smtpProperties, toAddress, subject, message, attachFiles);

JOptionPane.showMessageDialog(this,
"The e-mail has been sent successfully!");

} catch (Exception ex) {
JOptionPane.showMessageDialog(this,
"Error while sending the e-mail: " + ex.getMessage(),
"Error", JOptionPane.ERROR_MESSAGE);
}
}

private boolean validateFields() {
if (fieldTo.getText().equals("")) {
JOptionPane.showMessageDialog(this,
"Please enter To address!",
"Error", JOptionPane.ERROR_MESSAGE);
fieldTo.requestFocus();
return false;
}

if (fieldSubject.getText().equals("")) {
JOptionPane.showMessageDialog(this,
"Please enter subject!",
"Error", JOptionPane.ERROR_MESSAGE);
fieldSubject.requestFocus();
return false;
}

if (textAreaMessage.getText().equals("")) {
JOptionPane.showMessageDialog(this,
"Please enter message!",
"Error", JOptionPane.ERROR_MESSAGE);
textAreaMessage.requestFocus();
return false;
}

return true;
}

public static void main(String[] args) {
// set look and feel to system dependent
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception ex) {
ex.printStackTrace();
}

SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
new JEmail().setVisible(true);
}
});
}
}

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