Required String Parameter is not present?

Question

My Spring Boot project has a form at /albums/add which looks like this:

<form method="post">
    <input type="text" name="albumName"/>
    <input type="submit" value="Add album"/>
</form>

I'm trying to deal with that request in the controller below:

@Controller
@RequestMapping(value = "/albums")
public class AlbumController {

(...)

    @PostMapping("/add")
    public String processAddAlbumForm(@RequestParam String albumName) {
        albums.add(albumName);
        return "redirect:";
    }

}

However, Spring throws a 400 and tells me "Required String parameter 'albumName' is not present".

If I view the Network tab in my browser, I can see the request arrive with a value for albumName under the "Form Data" header, where the @RequestParam annotation can't seem to find it.

My code is copied directly from this tutorial, but I'm worried something might have deprecated since it was made - any ideas?

Your `form` doesn't have `action`. How will your controller be invoked? — Arvind Kumar Avinash, Dec 22 '20 at 19:13

burm87 · Accepted Answer · 2020-12-23T14:34:03.570

1

@RequestParam is used to retrieve parameters from the URL, but it also works to retrieve the parameter from an HTTP POST request and your code is working just fine on my local. What I see is that I'm being sent to a white label error page, is this the error you are referring to? In any case I cannot see any 500 being returned or any exception in the log. If you add the @ResponseBody annotation you will be able to send a string in the body of your response:

@PostMapping("/add")
@ResponseBody
public String processAddAlbumForm(@RequestParam String albumName) {
    albums.add(albumName);
    return "redirect:";
}

If you want to avoid using @ResponseBody in each method you could use @RestController instead of @Controller which is going to assume @ResponseBody by default.

The html I used to test the endpoint is the following, copied your piece of html and added the action property to specify the endpoint of my application:

<form action="http://localhost:8080/albums/add" method="post">
    <input type="text" name="albumName"/>
    <input type="submit" value="Add album"/>
</form>

The @RequestBody annotation is usually used when you are passing information in the body of your post request, usually in json format. In that case your form will have to send a json string like {"albumName": "my amazing album"}.

UPDATE

So, I've checked out your repository and it's actually not working. Adding the following dependency to your pom.xml is making the code I suggested working just fine:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

edited Dec 23 '20 at 14:34

answered Dec 22 '20 at 16:02

burm87

768
4
17

Do you know how exactly I would go about using this for the code above? I've tried `@RequestBody String body` and `@RequestBody Album album` (where album is a simple data class) but I get a 500 error in each case. – Liam Dec 22 '20 at 17:18
@Liam can you post details of your POST request? – burm87 Dec 22 '20 at 18:13
Hi @burm87 - I have made the changes you suggested, but unfortunately I'm still having problems! I managed to use the `@ModelAttribute` annotation to fix the problem in that instance, but now have another similar use case where I want to receive an array of integers from a form, which I can't figure out - line 44 [here](https://github.com/LiamBaines/spring-mvc-albums/blob/stack-overflow/src/main/java/com/plotto/springmvcalbums/controllers/AlbumController.java) – Liam Dec 23 '20 at 14:13
@Liam I've updated my answer, take a look and let me know. I think the starter-web dependency is missing to your pom.xml – burm87 Dec 23 '20 at 14:34
1

Bingo! It looks like the dependency has done the trick - thanks a lot, I never would have figured that out on my own :) – Liam Dec 23 '20 at 14:49
@Liam cool stuff. It looks like the remove is working fine as it is now. Let me know if that's the case ;) – burm87 Dec 23 '20 at 14:52

Required String Parameter is not present?

1 Answers1