四舍五入为两位数到小数点后三位，但小数点后第三位为零在Java中消失

Question

I want to round of my double to 3 decimal places in java.

I don't want to trim off the zero. So if my double is 2.34, I still want it as 2.340.

Answer 1

DecimalFormat myFormatter = new DecimalFormat("0.000");
String output = myFormatter.format(2.34d);

Answer 2

String res = String.format("%.3f", 2.34);

或者如果您想打印

System.out.printf( "%.3f",2.34);

Answer 3

use setMinimumFractionDigits and setRoundingMode

    final DecimalFormat df = new DecimalFormat();
    df.setMinimumFractionDigits(3);
    df.setRoundingMode(RoundingMode.HALF_UP);
    df.format(2.34);

Answer 4

使用以下十进制格式： 0.000

Answer 5

Following on from Tony Ennis's comment, you can't round a floating-point variable to a specific number of decimal places, or digits, without converting it into base-10. That's what the answers above are doing, and they are also converting it into displayable text.