What you are asking for is fundamentally wrong. POST requests sends data in a body payload, which is mapped via @RequestBody. @RequestParam is used to map data through the URL parameters such as /url?start=foo. What you are trying to do is use @RequestParam to do the job of @RequestBody.
Alternative solutions for REST controllers
- Introduce a DTO class. It is the most preferred and clean method.
- If you really want to avoid creating a class, you can use
@RequestBody Map<String, String> payload. Be sure to include'Content-Type': 'application/json'in your request header. - If you really want to use
@RequestParam, use a GET request instead and send your data via URL parameters.
Alternative solutions for MVC controllers
- Introduce a DTO class and use it with annotation
@ModelAttribute. - If you transform the form data into JSON, you can use
@RequestBody Map<String, String> payload. To do this, please see this answer.
It is not possible to map form data encoded data directly to a Map<String, String>.