java - How to use String as Velocity Template?

Question

What is the best way to create Velocity Template from a String?

I'm aware of Velocity.evaluate method where I can pass String or StringReader, but I'm curios is there a better way to do it (e.g. any advantage of creating an instance of Template).

Answer 1

There is some overhead parsing template. You might see some performance gain by pre-parsing the template if your template is large and you use it repeatedly. You can do something like this,

RuntimeServices runtimeServices = RuntimeSingleton.getRuntimeServices();
StringReader reader = new StringReader(bufferForYourTemplate);
Template template = new Template();
template.setRuntimeServices(runtimeServices);

/*
 * The following line works for Velocity version up to 1.7
 * For version 2, replace "Template name" with the variable, template
 */
template.setData(runtimeServices.parse(reader, "Template name")));

template.initDocument();

Then you can call template.merge() over and over again without parsing it everytime.

BTW, you can pass String directly to Velocity.evaluate().