Java keep trailing 0 in float operations

问题:

the code:

Float f = Float.parseFloat("1.80");
System.out.println(f);

prints "1.8" on screen. I need to keep the 0 in the float value (Float f) for some validation. How do I do this?

回答1:

You are confusing a number value and its formatting. It is not possible to actually store 1.80 as a float, however it is possible to display the number as a formatted String which forces two decimal places. Your options are:

1. Keep the original String that the user entered, if the number of decimal places they gave
   matters

2. Store the number as a float, but when displaying the number force it to display with two decimal places like this:

   System.out.printf("%.2f\n", f);

回答2:

That's simply a formatting issue:

System.out.printf("%.2f\n", f);

回答3:

1. Floating point variables don't have decimal places. They have binary places.
2. 1.8 and 1.80 are the same number, and they are represented the same way in a float or double.
3. If you want them presented with a certain number of decimal places, you have to convert to a decimal radix, via either BigDecimal or DecimalFormat, where you can control the number of decimal places.

In short the question doesn't really make sense as posed.