Groovy replacing place holders of file content similar to multiline-string - groovy

Question

Got the following script which replaces values in the multi line string.
def param1 = 'Groovy'
def param2 = 'Java'
def multiline = """
${param1} is closely related to ${param2},
so it is quite easy to make a transition.
"""
//output shows with the replaced values for param1 and param2
println multiline
Output is shown as expected:
Groovy is closely related to Java,
so it is quite easy to make a transition.
Issue:
Now I am trying to do the same using file instead of multi line string. i.e., copied the multi line string to a file and using the below script to do the same but not working(not giving the desired result).
I am sure, it must be something I am missing. Tried multiple way, but went futile.
Try #1: Script
def param1 = 'Groovy'
def param2 = 'Java'
def multiline = Eval.me(new File('test.txt').text)
println multiline
And it fails to run. Error follows:
org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
Script1.groovy: 1: expecting EOF, found ',' # line 1, column 42.
s closely related to ${param2},
^
1 error
Try #2
def param1 = 'Groovy'
def param2 = 'Java'
def multiline = new File('test.txt').text
def finalContent = """$multiline"""
println finalContent
And there is no difference in the output, just showing the file content as it is.
Output:
${param1} is closely related to ${param2},
so it is quite easy to make a transition.
Any pointers what am I missing?
Please note that at the moment I want to avoid file content modification using replace() method.

Answer 1

Not sure why it doesn't work, however what I may suggest here is that templating suits best here. Please have a look:
import groovy.text.SimpleTemplateEngine
def f = new File('lol.txt')
println f.text
def binding = [
param1: 'Groovy',
param2: 'Java',
]
def engine = new SimpleTemplateEngine()
def template = engine.createTemplate(f.text).make(binding)
println template.toString()
An explanation why file content is not evaluated may be found here.