can Velocity set a default value for a variable when no value found in VelocityContext?

Question

Velocity just print the tag name if no value was found in VelocityContext, ie, $name in my template file, but there is no value for \"name\" in VelocityContext, so just \"$n

Answer 1

Create a velocimacro in your template:

#macro(defaultValue $parm)  
#if (!$!parm || $!parm == "")  
i-like-will
#else  
$parm  
#end  
#end  

And call it like this in the same template:

#defaultValue($name)  

Check Apache Velocity - Velocity User Guide for more info on velocimacros (and velocity in general).