如何在Java中格式化数字？

import java.text.NumberFormat;

public class NumberFormatExample {
    public static void main(String[] args) {
        double number = 1234567.89;
        NumberFormat nf = NumberFormat.getInstance();
        String formattedNumber = nf.format(number);
        System.out.println("Formatted number: " + formattedNumber);
    }
}

import java.util.Formatter;

public class FormatterExample {
    public static void main(String[] args) {
        double number = 1234567.89;
        Formatter formatter = new Formatter();
        String formattedNumber = formatter.format("%,.2f", number).toString();
        System.out.println("Formatted number: " + formattedNumber);
    }
}