JTextField JFormattedTextField

import javax.swing.text.*;

public class ValoresMonetarios extends PlainDocument
{

 public static final int NUMERO_DIGITOS_MAXIMO = 12;

    @Override
 public void insertString(int offs, String str, AttributeSet a) throws BadLocationException
 {
  String texto = getText(0, getLength());
  for (int i = 0; i < str.length(); i++) {
      char c = str.charAt(i);
      if (!Character.isDigit(c)) {
          return;
      }
  }

   if(texto.length() < this.NUMERO_DIGITOS_MAXIMO){
          super.remove(0, getLength());
      texto = texto.replace(".", "").replace(",", "");
      StringBuffer s = new StringBuffer(texto + str);

   if (s.length() > 0 && s.charAt(0) == '0') {
       s.deleteCharAt(0);
   }

   if(s.length() < 3) {
     if (s.length() < 1) {
         s.insert(0,"000");
     }else if (s.length() < 2) {
         s.insert(0,"00");
   }else{
    s.insert(0,"0");
    }
   }

  s.insert(s.length()-2, ",");

  if(s.length() > 6) {
    s.insert(s.length()-6, ".");
  }

  if(s.length() > 10) {
    s.insert(s.length()-10, ".");
  }

  super.insertString(0, s.toString(), a);
  }
}

  public void remove(int offset, int length) throws BadLocationException {
    super.remove(offset, length);
      String texto = getText(0, getLength());
      texto = texto.replace(",", "");
      texto = texto.replace(".", "");
    super.remove(0, getLength());
    insertString(0, texto, null);
  }

}

seuJTextField.setDocument(new ValoresMonetarios());