Question

The title is not clear, so I write some sample to explain.

There is a string, which contains many nested {}s:

 /users/{<\w{2,4}\d{3}>id}

You can see I use {} as a placeholder for path variables, and it can have regex inside and which can also have {}.

How to write a regex with java to parse the path pattern, find the {} parts which don’t have outer {}. For this example, it should be {<\w{2,4}\d{3}>id}.

Thanks~

UPDATE

The given example is too simple, it can be:

/users/{<\w{2,4}\d{3}>id}/{action}/{<\w{2,4}\d{3}>targetId}

The result should be:

{<\w{2,4}\d{3}>id}
{action}
{<\w{2,4}\d{3}>targetId}

So \\{.*\\} doesn’t work.

Answer 1

Will you have such case as /users/{regex1}/{regex2} ?

If yes, in this case "\\{.*\\}" will return "{regex1}/{regex2}". 🙁

If not "\\{(.*)\\}" is good enough, being greedy you’ll go for the whole expression you asked for. 😉

EDIT:

With your edited question then the comment from @aix above was the right answer :
Find the `{}` part which doesn't have outer `{}` by regex

He pointed out your problem is similar with the one solved there: Regular Expression to match outer brackets