java - Difference between path and value attributes in @RequestMapping annotation

Question

What is the difference between below two attributes and which one to use when?

@GetMapping(path = "/usr/{userId}")
public String findDBUserGetMapping(@PathVariable("userId") String userId) {
  return "Test User";
}

@RequestMapping(value = "/usr/{userId}", method = RequestMethod.GET)
public String findDBUserReqMapping(@PathVariable("userId") String userId) {
  return "Test User";
}

question from:https://stackoverflow.com/questions/50351590/difference-between-path-and-value-attributes-in-requestmapping-annotation

Answer 1

As mentioned in the comments (and the documentation), value is an alias to path. Spring often declares the value element as an alias to a commonly used element. In the case of @RequestMapping (and @GetMapping, ...) this is the path property:

This is an alias for path(). For example @RequestMapping("/foo") is equivalent to @RequestMapping(path="/foo").

The reasoning behind this is that the value element is the default when it comes to annotations, so it allows you to write code in a more concise way.

Other examples of this are:

• @RequestParam (value → name)
• @PathVariable (value → name)
• ...

However, aliases aren't limited to annotation elements only, because as you demonstrated in your example, @GetMapping is an alias for @RequestMapping(method = RequestMethod.GET).

Just looking for references of AliasFor in their code allows you to see that they do this quite often.