How do I send an email with attachment?

By Wayan in Mail 10 Comments

In this example we create a small program to send email with a file attachment. To send message with attachment we need to create an email with javax.mail.Multipart object which basically will contain the email text message and then add a file to the second block, which both of them is an object of javax.mail.internet.MimeBodyPart. In this example we also use the javax.activation.FileDataSource.

package org.kodejava.mail;

import javax.activation.DataHandler;
import javax.activation.FileDataSource;
import javax.mail.*;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;
import java.util.Date;
import java.util.Properties;

public class SendEmailWithAttachment {
    public static void main(String[] args) {
        SendEmailWithAttachment demo = new SendEmailWithAttachment();
        demo.sendEmail();
    }

    public void sendEmail() {
        // Defines the E-Mail information.
        String from = "[email protected]";
        String to = "[email protected]";
        String subject = "Important Message";
        String bodyText = "This is a important message with attachment.";

        // The attachment file name.
        String attachmentName = "data.txt";

        // Creates a Session with the following properties.
        Properties props = new Properties();
        props.put("mail.smtp.host", "smtp.gmail.com");
        props.put("mail.transport.protocol", "smtp");
        props.put("mail.smtp.starttls.enable", "true");
        props.put("mail.smtp.port", "587");
        props.put("mail.smtp.ssl.protocols", "TLSv1.2");
        Session session = Session.getDefaultInstance(props);

        try {
            InternetAddress fromAddress = new InternetAddress(from);
            InternetAddress toAddress = new InternetAddress(to);

            // Create an Internet mail msg.
            MimeMessage msg = new MimeMessage(session);
            msg.setFrom(fromAddress);
            msg.setRecipient(Message.RecipientType.TO, toAddress);
            msg.setSubject(subject);
            msg.setSentDate(new Date());

            // Set the email msg text.
            MimeBodyPart messagePart = new MimeBodyPart();
            messagePart.setText(bodyText);

            // Set the email attachment file
            FileDataSource fileDataSource = new FileDataSource(attachmentName);

            MimeBodyPart attachmentPart = new MimeBodyPart();
            attachmentPart.setDataHandler(new DataHandler(fileDataSource));
            attachmentPart.setFileName(fileDataSource.getName());

            // Create Multipart E-Mail.
            Multipart multipart = new MimeMultipart();
            multipart.addBodyPart(messagePart);
            multipart.addBodyPart(attachmentPart);

            msg.setContent(multipart);

            // Send the msg. Don't forget to set the username and password
            // to authenticate to the mail server.
            Transport.send(msg, "kodejava", "password");
        } catch (MessagingException e) {
            e.printStackTrace();
        }
    }
}

Maven Dependencies

<dependencies>
    <dependency>
        <groupId>javax.mail</groupId>
        <artifactId>javax.mail-api</artifactId>
        <version>1.5.6</version>
    </dependency>
    <dependency>
        <groupId>javax.mail</groupId>
        <artifactId>mail</artifactId>
        <version>1.4.7</version>
    </dependency>
</dependencies>

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How do I split a string using Scanner class?

By Wayan in Core API, Util Package 0 Comment

Instead of using the StringTokenizer class or the String.split() method we can use the java.util.Scanner class to split a string.

package org.kodejava.util;

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class ScannerTokenDemo {
    public static void main(String[] args) {
        // This file contains some data as follows:
        // a, b, c, d
        // e, f, g, h
        // i, j, k, l
        File file = new File("data.txt");
        try {
            // Here we use the Scanner class to read file content line-by-line.
            Scanner scanner = new Scanner(file);
            while (scanner.hasNextLine()) {
                String line = scanner.nextLine();

                // From the above line of code we got a line from the file
                // content. Now we want to split the line with comma as the 
                // character delimiter.
                Scanner lineScanner = new Scanner(line);
                lineScanner.useDelimiter(",");
                while (lineScanner.hasNext()) {
                    // Get each split data from the Scanner object and print
                    // the value.
                    String part = lineScanner.next();
                    System.out.print(part + ", ");
                }                
                System.out.println();
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }
}

How do I read file line by line using java.util.Scanner class?

By Wayan in Core API, Util Package 0 Comment

Here is a compact way to read file line by line using the java.util.Scanner class.

package org.kodejava.util;

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class ScannerReadFile {
    public static void main(String[] args) {
        // Create an instance of File for data.txt file.
        File file = new File("README.md");
        try {
            // Create a new Scanner object which will read the data
            // from the file passed in. To check if there are more 
            // line to read from it, we call the scanner.hasNextLine() 
            // method. We then read line one by one till all lines 
            // is read.
            Scanner scanner = new Scanner(file);
            while (scanner.hasNextLine()) {
                String line = scanner.nextLine();
                System.out.println(line);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }
}

How do I send an email message?

By Wayan in Mail 0 Comment

To enable your application to send email you can use the JavaMail API, and prior to JDK 1.6 you will also need the JavaBeans Activation Framework. The JAF jar file should be included in your application classpath.

package org.kodejava.mail;

import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import java.util.Properties;

public class SendingEmailDemo {
    public static void main(String[] args) {
        String from = "[email protected]";
        String to = "[email protected]";
        String subject = "Hi There...";
        String text = "How are you?";

        // A properties to store mail server smtp information such as the host
        // name and the port number. With these properties we create a Session
        // object from which we'll create the Message object.
        Properties properties = new Properties();
        properties.put("mail.smtp.host", "smtp.gmail.com");
        properties.put("mail.transport.protocol", "smtp");
        properties.put("mail.smtp.starttls.enable", "true");
        properties.put("mail.smtp.port", "587");
        properties.put("mail.debug", "true");
        properties.put("mail.smtp.ssl.protocols", "TLSv1.2");
        Session session = Session.getDefaultInstance(properties, null);

        try {
            // Message is a mail msg to be sent through the Transport object.
            // In the Message object we set the sender address and the
            // recipient address. Both of this address is a type of
            // InternetAddress. For the recipient address we can also set the
            // type of recipient, the value can be TO, CC or BCC. In the next
            // two lines we set the email subject and the content text.
            Message msg = new MimeMessage(session);
            msg.setFrom(new InternetAddress(from));
            msg.setRecipient(Message.RecipientType.TO, new InternetAddress(to));
            msg.setSubject(subject);
            msg.setText(text);

            // Send the msg to the recipient.
            Transport.send(msg, "kodejava", "password");
        } catch (MessagingException e) {
            e.printStackTrace();
        }
    }
}

Maven Dependencies

<dependencies>
    <dependency>
        <groupId>javax.mail</groupId>
        <artifactId>javax.mail-api</artifactId>
        <version>1.5.6</version>
    </dependency>
    <dependency>
        <groupId>javax.mail</groupId>
        <artifactId>mail</artifactId>
        <version>1.4.7</version>
    </dependency>
</dependencies>

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How do I right justified JTextField contents?

By Wayan in Swing 0 Comment

To right justified a JTextField contents we can call the setHorizontalAlignment(JTextField.RIGHT) method of the JTextField class.

package org.kodejava.swing;

import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.WindowConstants;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.FlowLayout;

public class TextFieldRightJustify extends JFrame {
    public TextFieldRightJustify() {
        initComponents();
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> new TextFieldRightJustify().setVisible(true));
    }

    private void initComponents() {
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        setSize(500, 500);

        Container container = getContentPane();
        container.setLayout(new FlowLayout(FlowLayout.LEFT));

        JTextField textField = new JTextField(15);
        textField.setPreferredSize(new Dimension(100, 20));

        // Right justify the JTextField contents
        textField.setHorizontalAlignment(JTextField.RIGHT);

        container.add(textField);
    }
}