Allow @RequestParam, @PathVariable, and their siblings on fields

[behrangsa]

It is common to use abbreviated names for query parameters in GET requests.

For example:

GET /search?q=java&y=2019&l=eng

Where q means query, y means year, and l means language.

This can then be handled using a controller method:

public SomeResponse search(SearchRequest request) {
...
}

where:

public class SearchRequest {
   private String q;
   private String y;
   private String l;
}

However if we could apply @RequestParam on fields, then we could make SearchRequest more readable:

public class SearchRequest {
   @RequestParam("q")
   private String query;

   @RequestParam("y")
   private String year;

   @RequestParam("l")
   private String language;
}

As shown in the linked SO post, it is possible to customize Spring to do this using a custom annotation (e.g. @ParamName), but I think it would be cleaner and more elegant to allow @RequestParam (and @PathVariable, etc.) on POJO fields.

References

1. StackOverflow: How to customize parameter names when binding Spring MVC command objects.

[nictas]

This issue is a possible duplicate of #23094 and #21770, but I would really like to see it implemented. Not only will it solve the issue with shortened parameter names, but it would also allow us to construct a POJO from headers/parameters with names that are not legal Java identifiers (for example "x-cf-applicationid").

[behrangsa]

Also related: #22047.

[rstoyanchev]

This should be considered together with #22047 indeed, and there are also #23094 and #21770 that can be considered superseded.

[stdevi]

Hi, could you provide any recommendation on how to start proceeding with this feature?

[Johnny850807]

Hi, I'm new here.

I'm wondering if is it a good idea to introduce a new annotation like @ParamName and use it with @RequestParam to address the scenario mentioned in the original post. Here's an example:

public SomeResponse search(@RequestParam SearchRequest request) {
...
}

public class SearchRequest {
   @ParamName("q")
   private String query;

   @ParamName("q")
   private String year;

   @ParamName("q")
   private String language;
}