CODEWITHSUNDEEP
gwtstring-formattingnumber-formatting
Daniel F. O.
Daniel F. O.

Reputation: 11

GWT NumberFormat problems with high precision decimals

I'm using GWT 2.0 and when I try to use NumberFormat to format a Double the results are not as expected:

NumberFormat format = NumberFormat.getFormat( "#.########" );
Double d = new Double("0.256281093911");
format.format(d);

formatted string: 0.02147484

As you can see the formatted value is wrong (this can be seen in the gwt showcase). Is this something related to the custom format I'm using (#.########)? or is this a bug in the GWT formatter? If this is a bug, have someone found a workaround? Thanks.

Upvotes: 1

Views: 4515

Answers (2)

slartidan
slartidan

Reputation: 21586

A Double is stored in binary format in java in general. Working with binary float values is in most cases not what you want - conversion between binary and decimal floats causes rounding errors.

Try "BigDecimal", which stores float values in DECIMAL format, not in binary format.

Sample code:

NumberFormat format = NumberFormat.getFormat("#.########");
format.format(new BigDecimal("0.256281093911"));

Upvotes: 1

Gipsy King
Gipsy King

Reputation: 1577

link text you might try NumberFormat.getDecimalFormat. Also, it might have something to do with your browser's locale and/or it's decimal delimiter.

Upvotes: 1

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