两个精确字符串之间的正则表达式模式

Question

Hi I have this working code to detect a valid UUID pattern.

String pattern = "\\b[a-f0-9]{8}\\b-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-\\b[a-f0-9]{12}\\b";
Pattern r = Pattern.compile(pattern);
Matcher m = r.matcher(fileName);

This correctly detects strings like:

0101a8ef-db10-405a-a1d2-6bebdeb17625

I would like to add two exact strings on each side of this pattern like so:

FOLDER/0101a8ef-db10-405a-a1d2-6bebdeb17625.txt

Here is the code I am trying, but is not working:

String pattern = "FOLDER/\\b//[a-f0-9]{8}\\b-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-\\b[a-f0-9]{12}\\b.txt";
Pattern r = Pattern.compile(pattern);
Matcher m = r.matcher(uri.toString());

Answer 1

There is a // in the pattern that is not in the example string. Besides that, you can omit the word boundaries in between a character a-f0-9 and a - because it is implicit.

Note to escape the dot to match it literally, and you can add the word boundaries at the start and at the end to prevent partial matches.

You could update the pattern to

\\bFOLDER/[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}\\.txt\\b

See a regex demo .