JAX-RS @Path表达式中的路径参数是否必须用斜杠分隔？

Great question! Let’s cut to the chase first: No, JAX-RS path parameters do NOT require explicit slash separation in @Path expressions. The syntax you’re seeing is completely valid, and it’s using regex constraints to create flexible path matching logic.

Breaking Down That Special @Path Expression #

Let’s unpack the @Path annotation you found:

@Path("{foo: ([^/]+?)?}{bar: (/[^/]+?)?}")

Each part is an optional path parameter with regex rules:

• {foo: ([^/]+?)?}: Defines an optional foo parameter that matches any sequence of non-slash characters (or nothing at all, thanks to the trailing ?).
• {bar: (/[^/]+?)?}: Defines an optional bar parameter that matches a slash followed by non-slash characters (or nothing at all).

This setup lets the endpoint match multiple path patterns, like:

• The base path (empty, when both foo and bar are null)
• /myfoo (where foo = "myfoo" and bar is null)
• /myfoo/mybar (where foo = "myfoo" and bar = "/mybar")

Why This Works #

JAX-RS (per the JSR-339/JSR-370 specifications) allows path template segments to be concatenated directly without slashes, as long as the regex constraints are valid. The framework parses the entire @Path string as a single template, applying the regex rules to map incoming request paths to your parameters.

A Quick Note on Readability #

While this syntax is legal, it’s definitely not the most readable. If this endpoint doesn’t need to handle such a flexible range of paths, it’s better to use more explicit @Path annotations (e.g., multiple @Path declarations for different patterns) or comment the regex heavily to help future maintainers understand the intent.

内容的提问来源于stack exchange，提问作者David M. Karr