replace all occurrences of . for normalization

Question

Say I have the string "foo/./bar" then it should be normalized to "foo/bar". I tried doing this using the following regex:

String result = filePath.replaceAll("\\./", "");

but it didn't work out for me.. any idea?

Answer 1

In Java 7 there are built-in methods for this in the Path class. (If you're not using Java 7, then sorry.)

Either way, regexps are probably not the best way to implement path normalisation. It's a lot easier to do a split and then add the path elements to a stack, adding nothing when the element is . and popping if it's .. .

Answer 2

I guess what you want is to normalize a Windows filepath, not just to remove periods (in your example, you would have to remove a period and the following slash). So, why not use java.nio.Path ?

Path path = Paths.get(unnormalizedPath);
Path normalized = path.normalize();

Or with pre-Java7, you can do

new File(unnormalizedPath).getCanonicalPath();

Answer 3

Try this

System.out.println("./a/./b/c/."
                    .replaceAll("/[.]/|^[.]/","/")
                    .replaceAll("/[.]",""));

Output

/a/b/c