Allow @PathVariable to have default value on @ModelAttribute methods [SPR-12305]

[spring-projects-issues]

Manuel Jordan opened SPR-12305 and commented

The link shared above is going to be used to ask for many "improvements"

Here the summary of my request: If @RequestParam has the option to set a default value, would be viable add the same feature to @PathVariable?

It to work together with @ModelAttribute methods, in the same way @RequestParam does.

The reason in the link, see "Addition" and "Second Addition" sections

I want avoid create many @Controller's

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Affects: 4.0.7

Reference URL: http://stackoverflow.com/questions/25900993/spring-mvc-request-scope-trying-to-update-a-command-object-with-binder-setdisa

Issue Links:

• Improve Reference documentation @PathVariable, @RequestHeader & @RequestParam using Map<String, String> [SPR-12347] #16952 Improve Reference documentation @PathVariable, @RequestHeader & @RequestParam using Map<String, String>

[spring-projects-issues]

Rossen Stoyanchev commented

An optional @PathVariable argument on @ModelAttribute methods makes sense. The challenge is that on @RequestMapping methods it doesn't make sense so I don't think an annotation attribute is a choice here. It would help one case but cause confusion for the most common case.

Note that today @PathVariable can be used with Map<String, String> which gives you all path variables. It's less convenient since you have to parse Strings but it's one way.

We can consider some way to allow optional @PathVariable argument on @ModelAttribute methods as long as it is explicit. For example the combination @PathVariable with java.util.Optional from JDK 1.8 on @ModelAttribute methods.

[spring-projects-issues]

Manuel Jordan commented

Good to know it can has a solution, but I don't understand your explanation, in your convenience, would you share a simple snippet code (how a draft in a new comment) to understand your idea and see if it resolves my "Addition" and "Second Addition" sections of my shared link?

[spring-projects-issues]

Rossen Stoyanchev commented

Sure, for example:

@ModelAttribute("deportistaActualizar")
public Deportista populateActualizarFormulario(@PathVariable Map<String, String> pathVars){
    logger.info("populateActualizarFormulario - pathVars: {}", pathVars);
    String id = pathVars.get("id");
    return (id != null) ? this.fakeMultipleRepository.findDeportista(id) : null;
}

[spring-projects-issues]

Manuel Jordan commented

Note that today @PathVariable can be used with Map<String, String> which gives you all path variables. It's less convenient since you have to parse Strings but it's one way.

I don't remember have read an example about that on Spring Reference documentation.

Thanks by the snippet code. I understand now. Since it is a Map<String, String> I am assuming it should work for the following scenario:

• http://localhost:8080/spring-utility/deportista/1/detalle/something/88.htm

it to represents the URL:

deportista/{id}/detalle/something/{abc}

Then:

@ModelAttribute("deportistaActualizar")
public Deportista populateActualizarFormulario(@PathVariable Map<String, String> pathVars){
    logger.info("populateActualizarFormulario - pathVars: {}", pathVars);
    String id = pathVars.get("id");
    String abc = pathVars.get("abc"); //NEW 
    return (id != null) ? this.fakeMultipleRepository.findDeportista(id) : null;
}

Am I correct?

[spring-projects-issues]

Rossen Stoyanchev commented

Yes that's correct. It's basically a way to get all path variables in a map. The same pattern is also supported in other places (e.g. @RequestHeader, @RequestParam).

[spring-projects-issues]

Manuel Jordan commented

Thank you, I have checked the Spring Framework Reference Documentation and there is no an example about @PathVariable working together with Map<String, String> I have no checked the same for @RequestHeader, @RequestParam too

Should I create a new issue?

[spring-projects-issues]

Rossen Stoyanchev commented

Sure, thanks.

[spring-projects-issues]

Manuel Jordan commented

Sorry by the huge delay, busy a lot.

Here created Improve Reference documentation - create snippet code about @PathVariable (@RequestHeader & @RequestParam) working together with Map<String, String>

Thank You