Rounding a value in jsp by using JSTL Expressions

[venu babu.k]

hi,

This is venu,


Iam trying to round a double value in a jsp page with jstl expression, but it is showing error message.
If any body knows how to do please give suggestion me (or) any small example.

For example:

<input type="text" tabindex="2" value='<c:out value="${Obj.Value}"></c:out>' />

Here in above example i want to round of the value the Obj.Value

I tried with ${Math.round(Obj.Value)} but no use.



Thank you in advance.

[Bear Bibeault]

A few things:

1) Never say "I got an error". Show the error message.

2) Red text on tan is unreadable. Don't use color needlessly.

3) Be sure to disable smilies when posting code.

[Bear Bibeault]

venu babu.k wrote:I tried with ${Math.round(Obj.Value)} but no use.

Of course not. You can't just call methods with the EL.

The easiest thing to do, because the round() method is already a static method, is to define it as an EL function in a TLD. The you can use it from the EL easily.

[Stefan Evans]

Another potential way to do it is to use the <fmt:formatNumber> tag

<input type="text" tabindex="2" value='<fmt:formatNumber value="${Obj.Value}" maxFractionDigits="0"/>' /> 

It is almost equivalent to Math.round, but not quite. Math.round method always rounds a .5 up to the nearest whole number.
The number formatter uses the ROUND_EVEN approach, meaning if it is rounding .5, it will round to the nearest EVEN number (may be up or down)


One thing that bugs me looking at this code, is that you are putting a rounded result into an input field.
I'm of the opinion that if the value for that field is meant to be an integer, then Obj.Value should be an integer.
If this page is used for an edit screen, the value can change without user intervention because of your rounding here.
However you don't have a name attribute on this input field, so I guess you're not using it for submitting the page. Why then are you using <input type="text">??

[venu babu.k]

Thanks

For your suggestions,from next time i will follow the Conventions.I will try those 2 scenarios.