格式化双精度数，左侧和右侧为零

Question

I want to format a double with zeroes on the left and right as needed.

double myVal = 12.456;

Want string to be "012.456000"

I've tried:

String.format("%03.06f", myVal);

and other variations but it doesn't seem to format the text on the left side of the decimal place.

I'd prefer not to bring in a third party lib for this, if possible.

Answer 1

Use java.text.DecimalFormat :

double myVal = 12.456; 
DecimalFormat formatter = new DecimalFormat("000.000000");      
System.out.println(formatter.format(myVal));

Answer 2

This is the i18n (locale-specific) way:

double myVal = 12.456;
Locale locale = Locale.getDefault(); //replace this with actual locale
NumberFormat nf = NumberFormat.getNumberInstance(locale);
nf.setMinimumIntegerDigits(3);
nf.setMinimumFractionDigits(6);
System.out.println(nf.format(myVal)); //012.456000

Answer 3

I believe this is what you are looking for using the decimal format will give you however many zeros you want on the left and or right side of what you are formatting.

import java.text.*;
public class leftsideformat
{

  public static void main(String[] args)
  {
    double myVal  =12.456;
    DecimalFormat leftside = new DecimalFormat("000.0000000000");
    System.out.println(leftside.format(myVal));
  }

}