Limit RequestParam array size

Question

how can I limit @RequestParam array size in my endpoint ?? Is there any annotation for that ?

What I'm looking for is that I can send request with at most 5 parameters:

Correct request - http://localhost:8888/myEndpoint?param=foo1&param=foo2&param=foo3&param=foo4&param=foo5

Incorrect request(too many params) - http://localhost:8888/myEndpoint?param=foo1&param=foo2&param=foo3&param=foo4&param=foo5&param=foo6

Answer 1

You need to handle this in your server code. Take an array of request parameter and check on size. I do not know any annotation for that.

Answer 2

If it is not important how the parameter (keys) should be called you can use a Map<K,V> as @RequestParam

Limitation of a map entry is not possible through spring (found nothing about it). I also tried to add a Wrapper around it and Validate it with the annotation @Size, also not possible.

Solution you can use: Make an iterator out of the Map which is coming from the request as parameter and afterwards adding the entries to a new map.

@RequestMapping(value = "/test",method = RequestMethod.GET)
    public Object test(@RequestParam Map<String,String> map){

        Iterator<Map.Entry<String, String>> entries = map.entrySet().iterator();
        int counter = 0; //To limit the parameter
        Map<String,String> resultMap = new HashMap<>(); //Our result map which we will return
        while (entries.hasNext() && counter < 5) { //iterate over map and stop at five entries
            Map.Entry<String, String> entry = entries.next(); //get next entry
            resultMap.put(entry.getKey(),entry.getValue()); //Put the entry in our resultMAp
            counter++; //count up
        }
        return resultMap;
    }