java - Can I use @Requestparam annotation for a Post request?

Question

I have this controller method:

@PostMapping(
        value = "/createleave",
        params = {"start","end","hours","username"})
public void createLeave(@RequestParam(value = "start") String start,
                        @RequestParam(value = "end") String end,
                        @RequestParam(value = "hours") String hours,
                        @RequestParam(value = "username") String username){
    System.out.println("Entering createLeave " + start + " " + end + " " + hours + " " + username);
    LeaveQuery newLeaveQuery = new LeaveQuery();
    Account account = accountRepository.findByUsername(username);
    newLeaveQuery.setAccount(account);
    newLeaveQuery.setStartDate(new Date(Long.parseLong(start)));
    newLeaveQuery.setEndDate(new Date(Long.parseLong(end)));
    newLeaveQuery.setTotalHours(Integer.parseInt(hours));
    leaveQueryRepository.save(newLeaveQuery);
}

However when I send a post request to this endpoint I get the following

"{"timestamp":1511444885321,"status":400,"error":"Bad Request","exception":"org.springframework.web.bind.UnsatisfiedServletRequestParameterException","message":"Parameter conditions "start, end, hours, username" not met for actual request parameters: ","path":"/api/createleave"}"

When I remove the params argument from the @PostMapping annotation I get a more general error, it will say that it cannot find the first required parameter (start), while it really is being send together with the parameters end, hours and username.

how to get param in method post spring mvc?

I've read in this post that @RequestParam can only be used for get methods, but if I remove @RequestParam and stick with the params argument of the @PostMapping annotation it still doesn't work. I know I can use @RequestBody but I do not want to make a class just for those 4 parameters. Can anyone tell me how I can make this work?

Thank you

EDIT: I'm reading here https://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/web/bind/annotation/RequestMapping.html#params-- that the argument params isn't exactly what I thought it was. It seems to be used as a condition. If a set of parameters match a value then the endpoint controller method will be activated.

Answer 1

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>.