Using JAVA. I am trying to find a more elegant way for validating a Linux folder path (not including the file name).
What I have so far is this: "^\\\\/$|^((\\\\/([a-zA-Z0-9_-]+))+)$"
Folder paths should include only following characters: letters , numbers , dashes or underscore .
Valid/ matches:
/
/abc
/abc/abc/abc/abc
Invalid / not-matches:
/abc/
/abc/abc/abc/abc/
Your supplied RegEx is working on the test-cases.
You could even reduce it by removing backslashes \\\\
and outer pair of parentheses. Begin ^
and end $
are only needed once (around the two alternatives).
You can test the RegEx on RegexPlanet.com (click on Java-Button for tests)
^/|(/[a-zA-Z0-9_-]+)+$
or equivalent (see demo on RegexPlanet )
^/|(/[\w-]+)+$
Explained: \\w
matches a word-character (same as [a-zA-Z0-9_]
, not matching the dash ).
public boolean isValidLinuxDirectory(String path) {
Pattern linuxDirectoryPattern = Pattern.compile("^/|(/[a-zA-Z0-9_-]+)+$");
return path != null && !path.trim().isEmpty() && linuxDirectoryPattern.matcher( path ).matches();
}
File
Note the docs on isDirectory() :
Returns:
true
if and only if the file denoted by this abstract pathname exists and is a directory;false
otherwise
So it may only validate your requirements (valid Linux folder) if run on a Linux machine and if the folder/directory exists.
public boolean isValidExistingDirectory(String path) {
if (path == null || path.trim().isEmpty()) return false;
File file = new File( path );
return file.isDirectory();
}
As stated in comment the special form of root //
should also be valid. Then use this RegEx:
^/|//|(/[\w-]+)+$
It supports:
/
//
/abc/123/_abc-123
) Here ya go: \\/[a-zA-Z0-9_\\/-]*[^\\/]$
EDIT
First character matches a forward slash /
. The following character group matches az, AZ, 0-9, underscores, forward slashes, and dashes (all accepted directory and filename characters). The following asterisk makes the pattern match that character group 0 or more times (so any combo of those characters). The last character group has a negation ^
meaning it matches anything EXCEPT what's in the character group, being the final forward slash that we don't want to match. Finally the $
to end the string.
To cover all cases including the root directory, you will need the following:
^\/$|(\/[a-zA-Z_0-9-]+)+$
See Regex Demo using global and multiline modifiers.
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