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/abcInvalid / 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_-]+)+$");
return path != null && !path.trim().isEmpty() && linuxDirectoryPattern.matcher( path ).matches();
}
FileNote the docs on isDirectory():
Returns:
trueif and only if the file denoted by this abstract pathname exists and is a directory;falseotherwise
So it may only validate your requirements (valid Linux folder) if run on a Linux machine and if the folder/directory exists.
public boolean isValidExistingDirectory(String path) {
if (path == null || path.trim().isEmpty()) return false;
File file = new File( path );
return file.isDirectory();
}
As stated in comment the special form of root // should also be valid. Then use this RegEx:
^/|//|(/[\w-]+)+$
It supports:
////abc/123/_abc-123)
^/|/[a-zA-Z0-9_-]+)+$ does not work for the case where the folder path is //. ^/$|^(/[a-zA-Z0-9_-]+)+$ works.
^/$|^(/[a-zA-Z0-9_-]+)+$ does match the special-root (//) ??Here ya go:
\/[a-zA-Z0-9_\/-]*[^\/]$
EDIT
First character matches a forward slash /. The following character group matches a-z, A-Z, 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.
^\/([a-zA-Z0-9_\/-]*[^\/])?$To cover all cases including the root directory, you will need the following:
^\/$|(\/[a-zA-Z_0-9-]+)+$
See Regex Demo using global and multiline modifiers.
