如何在Java中为E表示法设置特定格式

Question

I need to convert some floats to format like this: 2,5000E-003 , 2,8625E+000

I know i can do it like this:

String.format("%s,%sE%s", digitInt, digitAfterDot, digitDegree)

But I hope somebody knows more clever and natty solution

Answer 1

You can use:

String.format("%1.4e",12345.67890123)

The result of this is:

1,2346e+04

Here is some documentation

EDIT
If you need 3 digits in the exponent, you can use the DecimalFormat Formatter:

DecimalFormat format = new DecimalFormat("0.0000E000");
System.out.print(format.format(12345.67890123f));

Which outputs:

1,2346E004

Note that it does not come with a positive sign if the exponent is positive. You can fix this with:

DecimalFormat format = new DecimalFormat("0.0000E000");
String result = format.format(12345.67890123f);
if (!result.contains("E-")) {
    result = result.replace("E", "E+");
}