除非有必要使用DecimalFormat，否则如何不显示小数位

Question

I'm modifying the following code to format doubles: "###,##0.#########". It generally works the way it should, but when I have a number like "123", it displays it as "123.0". How do I get it to avoid outputting the decimal place in that case? I just want "123" to show up.

After reading the Java tutorial, it seems as though it shouldn't display anything after the decimal place because everything after the decimal place in the formatting string is a pound sign, not a 0. But it's not behaving that way.

Also, why is the 0 there in the first place, before the decimal place, in the formatting string?

Edit: my full code is as follows. I'm new-ish to this project and still trying to figure out why it does this:

textField = new TextField("field", Double.class) {
    public org.apache.wicket.util.convert.IConverter getConverter(
            Class type) {
        DoubleConverter converter = (DoubleConverter) DoubleConverter.INSTANCE;
        java.text.NumberFormat numberFormat = converter
                .getNumberFormat(getLocale());
        java.text.DecimalFormat decimalFormat = (java.text.DecimalFormat) numberFormat;
        decimalFormat.applyPattern("###,##0.#########");
        converter.setNumberFormat(getLocale(),
                decimalFormat);
        return converter;
    };
};

Answer 1

The reason you're getting a 0 after the answer, is because you have set the answer to be a double . Doubles are set to be decimal answers. If there is nothing there to be a decimal answer, it will automatically place it as a 0, because there must be something after the decimal place.

If you want to get rid of the 0 after the answer, the simplest way would be to change the answer to an integer. However using an if statement to check whether it has only one 0 after the decimal place, would allow you to have both an integer answer and a double answer.