"I have a problem with some links getting white spaces automatically"

How does the "automatically" part occur? The whitespace fairy doesn't pay you a visit... so when are these whitespaces being introduced? Usually that occurs when a file has a space in the filename, and a browser intelligently converts that space to a %20 to avoid a global meltdown. I think rather than converting the spaces, you should avoid them in the first place by fixing the source filenames (or what creates them if it's another process.)

In other words, If you have a file called "sample file.html", and you want to access it via a browser, you will have to use "http://yourserver.com/sample%20file.html" to reference it. Instead of trying to fix the URL, remove the space in the file name, perhaps "sample_file.html", so your URL will not have any %20 characters present. Would that solve your problem?