With Rest DSL, how to proxy all of url path without listing each one of them

Issue

With Rest DSL, how to proxy all of url path without listing each one of them?
For example
localhost:8001/service/a -> back:9001/service/a
localhost:8001:service/b/c -> back:9001/service/b/c
localhost:8001:service/d/e/f -> back:9001/service/d/e/f

In the future, the backend server might provide another service, so it's better to proxy those new services without modifying the existing rest DSL.