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
A For number or letter
* For anything
L For letter, it will be converted to the equivalent lower case
U For letter, it will be converted to the equivalent upper case
H For hexa decimal value
To escape another mask character

Wayan Saryada

A programmer, runner, recreational diver, currently living in the island of Bali, Indonesia. Mostly programming in Java, creating web based application with Spring Framework, JPA, etc. If you need help on Java programming you can hire me on Fiverr.

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