How do I use JFormattedTextField to format user input?

The JFormattedTextField allows us to create a text field that can accept a formatted input. In this example we create two formatted text fields that accept a valid phone number and date.

package org.kodejava.example.swing;

import javax.swing.*;
import javax.swing.text.MaskFormatter;
import javax.swing.text.DateFormatter;
import java.awt.*;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.text.ParseException;
import java.util.Date;

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

    private void initComponents() {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(new Dimension(200, 200));
        getContentPane().setLayout(new FlowLayout(FlowLayout.LEFT));

        MaskFormatter mask = null;
        try {
            //
            // Create a MaskFormatter for accepting phone number, the # symbol accept
            // only a number. We can also set the empty value with a place holder
            // character.
            //
            mask = new MaskFormatter("(###) ###-####");
            mask.setPlaceholderCharacter('_');
        } catch (ParseException e) {
            e.printStackTrace();
        }

        //
        // Create a formatted text field that accept a valid phone number.
        //
        JFormattedTextField phoneField = new JFormattedTextField(mask);
        phoneField.setPreferredSize(new Dimension(100, 20));

        //
        // Here we create a formatted text field that accept a date value. We
        // create an instance of SimpleDateFormat and use it to create a
        // DateFormatter instance which will be passed to the JFormattedTextField.
        //
        DateFormat format = new SimpleDateFormat("dd-MMMM-yyyy");
        DateFormatter df = new DateFormatter(format);
        JFormattedTextField dateField = new JFormattedTextField(df);
        dateField.setPreferredSize(new Dimension(100, 20));
        dateField.setValue(new Date());

        getContentPane().add(phoneField);
        getContentPane().add(dateField);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new FormattedTextFieldExample().setVisible(true);
            }
        });
    }
}

Here are some other characters that can be used in the MaskFormatter class.

#For number
?For letter
AFor number or letter
*For anything
LFor letter, it will be converted to the equivalent lower case
UFor letter, it will be converted to the equivalent upper case
HFor hexa decimal value
To escape another mask character

Wayan Saryada

I am a programmer, a runner, an open water diver and currently living in the island of Bali, Indonesia. If you need help on Java programming you can hire me on Fiverr.

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