Displaying a number in 2 point decimal format in jsf

问题

I am using JSF 2 and RichFaces 3. Here in the picture shown below, numbers are being displayed as what they are in the database.

But I want to display them as 6749395.20 if fraction part is there and 5095138.00 if no fraction part is there.

As of now I have tried something like this.

 <rich:column>
    <f:facet name="header">
        <h:outputText value="Total Amount"/>
    </f:facet>
    <h:outputText value="#{rr[2]}">
        <f:convertNumber type="number" groupingUsed="true" minFractionDigits="2" pattern="#0.00"/>
    </h:outputText>
 </rich:column>

Actually I am showing all of them together, but I have tried with all of them as all possible combinations with type, groupingUsed, minFractionDigits and pattern.

Why does it not work? How is this caused and how can I solve it?

回答1:

That can happen if the value is not a Number at all, for example a String. You're then basically using the wrong type for the data it represents. To represent currencies in Java, you should be using BigDecimal. Also, make sure that the type in the database table is right, i.e. it should not be a varchar, but a decimal.

Once you've fixed the data type, then the <f:convertNumber> will work as you told it to do. Note that the pattern attribute will override the groupingUsed and minFractionDigits. You should use either the pattern or the others. Also, type="number" is already the default, so it can be removed.

So, either use

<f:convertNumber pattern="#0.00" />

or

<f:convertNumber groupingUsed="true" minFractionDigits="2" />

Note that they generate different formats. You probably want to set grouping to false.

You can also use type="currency", it will then automatically apply the right pattern as per the UIViewRoot#getLocale():

<f:convertNumber type="currency" />

See also the tag library documentation and the DecimalFormat javadoc.

来源：https://stackoverflow.com/questions/10412908/displaying-a-number-in-2-point-decimal-format-in-jsf