Create and iterate through an array in Velocity Template Language

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According to Apache Velocity User Guide, right hand side of assignments can be of type

  • Variable reference
  • List item
  • String literal
  • Property reference
  • Method reference
  • Number literal
  • ArrayList
  • Map

You can create an empty list, which would satisfy all your needs for an array, in an Apache Velocity template with an expression like:

#set($foo = [])

or initialize values:

#set($foo = [42, "a string", 21, $myVar])

then, add elements using the Java add method:

$foo.add(53);
$foo.add("another string");

but beware, as the Java .add() method for the list type returns a boolean value, when you add an element to the list, Velocity will print, for instance, “true” or “false” based on the result of the “add” function.

A simple work around is assigning the result of the add function to a variable:

#set($bar = $foo.add(42))

You can access the elements of the list using index numbers:

<span>$foo[1]</span>

Expression above would show a span with the text “a string”. However the safest way to access elements of a list is using foreach loops.

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