如何格式化 Velocity 模板中的数字？

Question

I am getting a java object in my velocity template. The object has a double value which I want to format to 2 decimal places and display it in my template.

The class for which im getting an object is something like this

Class Price
{
double value;
String currency;
}

In my velocity template, im getting the value like this

$price.value

but I need to format it to 2 decimal places before displaying it.

I want to convert

23.59004 to 23.59

35.7 to 35.70

3.0 to 3.00

9 to 9.00

Please tell me how can I do it in velocity template? I searched a lot for this and found that I can use velocity tools, but there are no examples related to it? and can i use velocity tools in templates?

Answer 1

Velocity tools are expected to be used in Velocity templates; essentially they are objects added to the variables available in a template so that you can use $numberTool.format("#0.00", $val) or similar. If none of the available tools don't fit your needs, simply create a POJO and add it to the template.

To make it working you also should add the following maven dependency:

<dependency>
    <groupId>org.apache.velocity</groupId>
    <artifactId>velocity-tools</artifactId>
    <version>2.0</version>
</dependency>

and write following code:

context.put("numberTool", new NumberTool());

Answer 2

#set($String = "abc")
$String.format("%.2f", $val)

$val has to be Double or Float in this case...

Answer 3

使用 VelocityTools 项目中的 MathTool。

$math.roundTo(2, $val)

Answer 4

formatCurrency($value). This is good java velocity code to format a number to currency format.

Answer 5

$numberTool.format("#0.00", $val)

Answer 6

A better way to do things besides using $numberTool.format is to use one of the MessageFormat -based tool classes that do more than just numbers. For example, we use MessageTool which is Struts-specific, but you can use something similar like ResourceTool instead:

resources.properties
some.key=The price is currently {0,number,$#.##}

template.vm
<p>
  $msg.get('some.key', 'resources', [$price])
</p>

This way, you get the number in context and not just all by itself. In a non-English language, the number might be more appropriate to come to the left of the text, or in the middle, or whatever. This gives you much more flexibility than simply formatting the number all by itself.

Answer 7

Solution by just using the Java Formatters: (without additional libraries)

NumberFormat decimalFormat = new DecimalFormat("#.00");
velocityContext.put("decimalFormat", decimalFormat);

Int Number: $decimalFormat.format($obj.intNum)

And here is how the timestamp is formatted to human readable date.

DateFormat DATETIME_FORMAT = new SimpleDateFormat("dd/MM/yyyy HH:mm:ss");
velocityContext.put("datetimeFormat", DATETIME_FORMAT);

Timestamp to Date: $datetimeFormat.format($obj.timestamp)