Managing absolute path and full path

I've created a small program wich can read a .txt file.

This file contains a link to another file in this format new_file.txt

The goal is to return the path of the new file, so basically I'm doing this :

开发者_如何转开发String newFileName = getFileName();
int index = oldFilePath.lastIndexOf('\\');
String path = oldFilePath.substring(0, index + 1);
String newFilePath = path + newFileName;
return newFilePath;

For example :

The first file I opened is : C:\a\b\c\oldFile.txt

In this file I found newFile.txt

So the new path will be : C:\a\b\c\newFile.txt

Nice, but what If I find something like this :

..\ or .\.\ or ...

Is there any way to automate this mess ?

Thanks

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In C#/.Net you have the rather cool Path class.

You can use Path.GetFullPath( string pathname ) to resolve paths e.g. with \..\ etc in them.

Use Path.GetDirectory(), Path.GetFileName(), Path.GetFileNameWithoutExtension() & Path.GetExtension() to pull names apart and Path.Combine() to put them back together again.

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You've tagged this as java as well as c#

In java look at FileNameUtils http://commons.apache.org/io/apidocs/org/apache/commons/io/FilenameUtils.html

The normalize method should help