How to implement in Java ( JTextField class ) to allow entering only digits?

How to implement in Java ( JTextField class ) to allow entering only digits?

Solution 1:

Add a DocumentFilter to the (Plain)Document used in the JTextField to avoid non-digits.

PlainDocument doc = new PlainDocument();
doc.setDocumentFilter(new DocumentFilter() {
    @Override
    public void insertString(FilterBypass fb, int off, String str, AttributeSet attr) 
        throws BadLocationException 
    {
        fb.insertString(off, str.replaceAll("\\D++", ""), attr);  // remove non-digits
    } 
    @Override
    public void replace(FilterBypass fb, int off, int len, String str, AttributeSet attr) 
        throws BadLocationException 
    {
        fb.replace(off, len, str.replaceAll("\\D++", ""), attr);  // remove non-digits
    }
});

JTextField field = new JTextField();
field.setDocument(doc);

Solution 2:

Use a JFormattedTextField.

http://download.oracle.com/javase/tutorial/uiswing/components/formattedtextfield.html

Solution 3:

Use a Document implementation whose insertString method filters out the non-digit characters.

Solution 4:

Use this class, and call it where you need to validation pass your jtexField name as parameter.

 exm:- setNumericOnly(txtMSISDN); here txtMSISDN is my jtextField.

  public static void setNumericOnly(JTextField jTextField){
    jTextField.addKeyListener(new KeyAdapter() {
         public void keyTyped(KeyEvent e) {
           char c = e.getKeyChar();
           if ((!Character.isDigit(c) ||
              (c == KeyEvent.VK_BACK_SPACE) ||
              (c == KeyEvent.VK_DELETE))) {
                e.consume();
              }
         }
    });
}