Java regular expression for file path

Question

I am developing an application a where user need to supply local file location or remote file location. I have to do some validation on this file location.
Below is the requirement to validate the file location.

Path doesn't contain special characters * | " < > ? .
And path like "c:" is also not valid.

Paths like

• c:\\ ,
• c:\\newfolder ,
• \\\\casdfhn\\share

are valid while

• c:
• non ,
• \\\\casfdhn

are not.

I have implemented the code based on this requirement:

String FILE_LOCATION_PATTERN = "^(?:[\\w]\\:(\\[a-z_\\-\\s0-9\\.]+)*)";
String REMOTE_LOCATION_PATTERN = "\\\\[a-z_\\-\\s0-9\\.]+(\\[a-z_\\-\\s0-9\\.]+)+";

Pattern locationPattern = Pattern.compile(FILE_LOCATION_PATTERN);
Matcher locationMatcher = locationPattern.matcher(iAddress);
if (locationMatcher.matches()) {
    return true;
}

locationPattern = Pattern.compile(REMOTE_LOCATION_PATTERN);
locationMatcher = locationPattern.matcher(iAddress);

return locationMatcher.matches();

Test:

worklocation'        pass
'C:\dsrasr'          didnt pass  (but should pass)
'C:\saefase\are'     didnt pass  (but should pass)
'\\asfd\sadfasf'     didnt pass  (but should pass)
'\\asfdas'           didnt pass  (but should not pass)
'\\'                 didnt pass  (but should not pass)
'C:'                 passed infact should not pass

I tried many regular expression but didn't satisfy the requirement. I am looking for help for this requirement.

Answer 1

The following should work:

([A-Z|a-z]:\\[^*|"<>?\n]*)|(\\\\.*?\\.*)

The lines highlighted in green and red are those that passed. The non-highlighted lines failed.

Bear in mind the regex above is not escaped for java

Answer 2

from your restrictions this seems very simple.

^(C:)?(\\\\[^\\\\"|^<>?\\\\s]*)+$

Starts with C:\\ or slash ^(C:)?\\\\

and can have anything other than those special characters for the rest ([^\\\\"|^<>?\\\\s\\\\\\])*

and matches the whole path $

Edit: seems C:/ and / were just examples. to allow anything/anything use this:

^([^\\\\"|^<>?\\\\s])*(\\\\[^\\\\"|^<>?\\\\s\\\\\\]*)+$