希望得到帮助格式化一个jformattedtextfield只接受数字，而作为一个矩阵

NumberFormat longFormat = NumberFormat.getIntegerInstance();
    NumberFormatter numberFormatter = new NumberFormatter(longFormat);
    numberFormatter.setAllowsInvalid(false);
    numberFormatter.setMinimum(0);
    numberFormatter.setMaximum(10);

    gameboard = new JFormattedTextField[9][9](numberFormatter);