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.

Question already answered here: http://stackoverflow.com/a/42036026/1951947 — raythurnevoid, Feb 06 '17 at 09:01

score 4 · Accepted Answer · answered Jun 12 '14 at 20:17

4

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

enter image description here

answered Jun 12 '14 at 20:17

user184994

17,791
1
46
52

1

Which tool is this? – neowulf33 Jan 10 '17 at 21:44

Adam Yost · Answer 2 · 2014-06-12T20:04:32.443

1

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\\\]*)+$

edited Jun 12 '14 at 20:04

answered Jun 12 '14 at 19:20

Adam Yost

3,616
23
36

its not necessary to have C: it can be anything – MrSham Jun 12 '14 at 19:28
I also tried this I am getting error: java.util.regex.PatternSyntaxException: Unmatched closing ')' near index 27 ^([^"|^<>?\s])*\([^"|^<>?\s])*$ ^ – MrSham Jun 12 '14 at 19:47
I also tried mine on internet it works but didnt in java using pattern class and matcher – MrSham Jun 12 '14 at 19:50
in java did you guys make sure to double escape? the "\" need to be "\\" in java. Edited the answer to use double escapes – Adam Yost Jun 12 '14 at 19:56
yeah i made that changes.."^([^\\\"|^<>?\\s])*\\\\([^\\\"|^<>?\\s])*$".. it works fine.. thanks – MrSham Jun 12 '14 at 19:58
but how can i avoid : "\\asdfas" and "\\" this should not pass – MrSham Jun 12 '14 at 20:00
too many escapes. just 2, you have 3. if you want no double slashes (which are a valid filepath component btw) I will edit it as such. – Adam Yost Jun 12 '14 at 20:02
valid path is c:\, c:\newfolder, \\casdfhn\share – MrSham Jun 12 '14 at 20:05

Java regular expression for file path

2 Answers2