How to access HTTP request data (query parameters, headers, body) in Spring MVC?

In Spring MVC, access to HTTP request data can be obtained using annotations in controller methods:

• Query parameters: use @RequestParam
• Headers: use @RequestHeader
• Request body: use @RequestBody

Example:

@RestController
public class MyController {

    @GetMapping("/example")
    public String example(
        @RequestParam String param,               // query parameter
        @RequestHeader("User-Agent") String ua) { // header
        return "Param: " + param + ", UA: " + ua;
    }

    @PostMapping("/submit")
    public ResponseEntity<String> submit(@RequestBody MyDto dto) { // request body
        // process dto
        return ResponseEntity.ok("Received");
    }
}

Thus, Spring MVC automatically binds parts of the HTTP request to controller method parameters.