Velocity Templates and Newlines

If you're reading this article you've probably encounted the same problem as I have. I was trying to put a newline '\n' character in the value of a variable in a Velocity template.

Attempt 1:

I assumed \n would work...

#if ( !$foo )
  #set ( $foo = "There was no foo set in the Context.\nPlease do something about it." )
#end

This produced There was no foo set in the Context.\nPlease do something about it. as the value of $foo.

Attempt 2:

I just thought this was worth a shot :D

#if ( !$foo )
  #set ( $foo = "There was no foo set in the Context.
Please do something about it." )
#end

And the template failed to compile

Solution:

Basically, the easiest way I found is to place the newline, carriage return or other special character in the context.

public Template handleRequest( HttpServletRequest request, HttpServletResponse response, Context context )
{
    ...

    context.put( "nl", "\n" );
    context.put( "cr", "\r" );

    ...
}

And in your template:

#if ( !$foo )
  #set ( $foo = "There was no foo set in the Context.${nl}Please do something about it." )
#end

Maybe not the best solution but it works for me. If you expect to use it across your entire application I suggest you override VelocityServlet.createContext in your Servlet to add these characters to every context in your application.

Example:

protected Context createContext( HttpServletRequest request, HttpServletResponse response ) {
    Context context = super.createContext( request, response );
   
    context.put( "nl", "\n" );
    context.put( "cr", "\r" );
   
    return context;
}

About this entry

You’re currently reading “Velocity Templates and Newlines,” an entry on Weblog of Michael Cutler

Published:
21st July 2005 / 10:07pm
Category:
Jakarta Velocity

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