Spring Boot Controller Multiple parameters (<List> and multipart file) object

Question

Hello i am looking if i can handle with only one RestController method multiple params... with controllers method it could be done... but i couldnt find project with 2 like that.

@PostMapping(value ="upload")
    public upload(@RequestParam MultipartFile file,@RequestParam List<String> myParams ){
     some code here ....
        return;
    }

I am just wondering if is also a good practise ... having two deferent type of objects in same controller and if its possible,,, any idea????

Answer 1

Simple answer: Yes, that's possible.
But as you asked for good practice, here's some context:

It is very helpful to understand how HTTP actually transports data.

If your request uses GET as request method, parameters are added to the URL as a query string. That could look like this: http://example.com/index?param1=value1&param2=value2

In this case, Spring maps the key-value pairs from the query string to your method arguments. But this will only work for text.

If you're using POST, the data is sent inside the request body. How that is encoded depends on the media type of your data. For example, the default media type application/x-www-form-urlencoded would encode the data to the same query string as above.

If you want to upload mixed-type form data like a file/blob along with some textual parameters, your data should be encoded with multipart/form-data.

As long as the request body contains a key-value format, Spring Boot will still be able to distinguish and map the parameters via @RequestParam (If the keys don't differ from your attribute names, you don't even need to assign a name to the value attribute).

I highly recommend you to take a look at the @RequestBody and @RequestPart annotations as i think it often is best practice to use a model class (DTO) for the whole request body (or rather the form, semantically), especially if there are a lot of parameters to process.