Formatting a double in JSF

decimalformattingjsf

I have a problem similar to the one found here : JSF selectItem label formatting.

What I want to do is to accept a double as a value for my and display it with two decimals. Can this be done in an easy way?

I've tried using but that seems to be applied on the value from the inputText that is sent to the server and not on the initial value in the input field.

My code so far:

<h:inputText id="december" value="#{budgetMB.december}" onchange="setDirty()" styleClass="StandardBlack">
    <f:convertNumber maxFractionDigits="2" groupingUsed="false" />
</h:inputText>

EDIT: The above code actually works. I was fooled by JDeveloper that didn't update the jsp page even when I did a explicit rebuild of my project and restarted the embedded OC4J server. However, after a reboot of my computer everything was fine.

Best Solution

If I'm not misunderstanding your requirement, I was able to achieve formatting of the value in the input box during the rendering of the view with:

<h:inputText id="text1" value="#{...}">
    <f:convertNumber pattern="#,###,##0.00"/>
</h:inputText>

I was using the Standard Faces Components in my vendor-branded Eclipse so I'm assuming the pattern attribute is part of standard JSF.

Related Solutions

C# – How to convert a Decimal to a Double in C#

An explicit cast to double like this isn't necessary:

double trans = (double) trackBar1.Value / 5000.0;

Identifying the constant as 5000.0 (or as 5000d) is sufficient:

double trans = trackBar1.Value / 5000.0;
double trans = trackBar1.Value / 5000d;

.net – Difference between decimal, float and double in .NET

float and double are floating binary point types. In other words, they represent a number like this:

10001.10010110011

The binary number and the location of the binary point are both encoded within the value.

decimal is a floating decimal point type. In other words, they represent a number like this:

12345.65789

Again, the number and the location of the decimal point are both encoded within the value – that's what makes decimal still a floating point type instead of a fixed point type.

The important thing to note is that humans are used to representing non-integers in a decimal form, and expect exact results in decimal representations; not all decimal numbers are exactly representable in binary floating point – 0.1, for example – so if you use a binary floating point value you'll actually get an approximation to 0.1. You'll still get approximations when using a floating decimal point as well – the result of dividing 1 by 3 can't be exactly represented, for example.

As for what to use when:

For values which are "naturally exact decimals" it's good to use decimal. This is usually suitable for any concepts invented by humans: financial values are the most obvious example, but there are others too. Consider the score given to divers or ice skaters, for example.
For values which are more artefacts of nature which can't really be measured exactly anyway, float/double are more appropriate. For example, scientific data would usually be represented in this form. Here, the original values won't be "decimally accurate" to start with, so it's not important for the expected results to maintain the "decimal accuracy". Floating binary point types are much faster to work with than decimals.

Best Solution

Related Solutions

C# – How to convert a Decimal to a Double in C#

.net – Difference between decimal, float and double in .NET

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