How to test with MockMVC a Map parameter in Spring Rest

Question

In Spring Rest, I have a RestController exposing this method:

@RestController
@RequestMapping("/controllerPath")
public class MyController{
    @RequestMapping(method = RequestMethod.POST)
    public void create(@RequestParameter("myParam") Map<String, String> myMap) {
         //do something
    }
}

I'd like to have this method tested, using MockMVC from Spring:

// Initialize the map
Map<String, String> myMap = init();

// JSONify the map
ObjectMapper mapper = new ObjectMapper();
String jsonMap = mapper.writeValueAsString(myMap);

// Perform the REST call
mockMvc.perform(post("/controllerPath")
            .param("myParam", jsonMap)
            .andExpect(status().isOk());

The problem is I get a 500 HTTP error code. I'm pretty sure this comes from the fact that I use a Map as a parameter of my controller (I tried changing it to String and it works).

The question is: How can I do to have a Map in parameter in my RestController, and test it correctly using MockMVC?

Thanks for any help.

If you get an internal server error you should also have a stack trace somewhere. How does the setup of your test class look like, It might also be the case that there is something wrong. — hotzst, Oct 01 '15 at 11:13
You're right. After looking deeply in my log, I could find this: "Failed to convert value of type 'java.lang.String' to required type 'java.util.Map'; nested exception is java.lang.IllegalStateException: Cannot convert value of type [java.lang.String] to required type [java.util.Map]: no matching editors or conversion strategy found". In other words, how could I specify a map to MockMVC as a parameter, to match the one in the method of my controller? — Rémi Doolaeghe, Oct 01 '15 at 12:58
Have a look at http://stackoverflow.com/questions/21175066/testing-spring-mvc-request-parameter-map-and-multipartfile-with-mockmvc — hotzst, Oct 01 '15 at 13:09
I used GSon instead of the ObjectMapper, as mentionned in your link, without success (same result)... Any other idea? — Rémi Doolaeghe, Oct 01 '15 at 13:31
Ok, I found the reason, I think. NEVER use directly a map as a parameter, always wrap it in a Wrapper class. — Rémi Doolaeghe, Oct 02 '15 at 10:26

score 5 · Answer 1 · edited Jun 15 '21 at 09:12

I know this is an old post but I came across the same problem and I ended up solving it as follows:

My controller was (Check that RequestParam has no name):

@GetMapping
public ResponseEntity findUsers (@RequestParam final Map<String, String> parameters) {
//controller code
}

In my unit test I did:

MultiValueMap<String, String> parameters = new LinkedMultiValueMap<>();
parameters.put("name", Collections.singletonList("test"));
parameters.put("enabled", Collections.singletonList("true"));

final MvcResult result = mvc.perform(get("/users/")
                .params(parameters)
                .contentType(MediaType.APPLICATION_JSON_UTF8))
                .andExpect(status().isOk())
                .andReturn();

How to test with MockMVC a Map parameter in Spring Rest

1 Answers1