Testing Spring's @RequestBody using Spring MockMVC

Question

I am trying to test a method that posts an object to the database using Spring's MockMVC framework. I've constructed the test as follows:

@Test
public void testInsertObject() throws Exception { 

    String url = BASE_URL + "/object";

    ObjectBean anObject = new ObjectBean();
    anObject.setObjectId("33");
    anObject.setUserId("4268321");
    //... more

    Gson gson = new Gson();
    String json = gson.toJson(anObject);

    MvcResult result = this.mockMvc.perform(
            post(url)
            .contentType(MediaType.APPLICATION_JSON)
            .content(json))
            .andExpect(status().isOk())
            .andReturn();
}

The method I'm testing uses Spring's @RequestBody to receive the ObjectBean, but the test always returns a 400 error.

@ResponseBody
@RequestMapping(    consumes="application/json",
                    produces="application/json",
                    method=RequestMethod.POST,
                    value="/object")
public ObjectResponse insertObject(@RequestBody ObjectBean bean){

    this.photonetService.insertObject(bean);

    ObjectResponse response = new ObjectResponse();
    response.setObject(bean);

    return response;
}

The json created by gson in the test:

{
   "objectId":"33",
   "userId":"4268321",
   //... many more
}

The ObjectBean class

public class ObjectBean {

private String objectId;
private String userId;
//... many more

public String getObjectId() {
    return objectId;
}

public void setObjectId(String objectId) {
    this.objectId = objectId;
}

public String getUserId() {
    return userId;
}

public void setUserId(String userId) {
    this.userId = userId;
}
//... many more
}

So my question is: how to I test this method using Spring MockMVC?

Answer 1

Use this one

public static final MediaType APPLICATION_JSON_UTF8 = new MediaType(MediaType.APPLICATION_JSON.getType(), MediaType.APPLICATION_JSON.getSubtype(), Charset.forName("utf8"));

@Test
public void testInsertObject() throws Exception { 
    String url = BASE_URL + "/object";
    ObjectBean anObject = new ObjectBean();
    anObject.setObjectId("33");
    anObject.setUserId("4268321");
    //... more
    ObjectMapper mapper = new ObjectMapper();
    mapper.configure(SerializationFeature.WRAP_ROOT_VALUE, false);
    ObjectWriter ow = mapper.writer().withDefaultPrettyPrinter();
    String requestJson=ow.writeValueAsString(anObject );

    mockMvc.perform(post(url).contentType(APPLICATION_JSON_UTF8)
        .content(requestJson))
        .andExpect(status().isOk());
}

As described in the comments, this works because the object is converted to json and passed as the request body. Additionally, the contentType is defined as Json (APPLICATION_JSON_UTF8).

More info on the HTTP request body structure

Answer 2

the following works for me,

  mockMvc.perform(
            MockMvcRequestBuilders.post("/api/test/url")
                    .contentType(MediaType.APPLICATION_JSON)
                    .content(asJsonString(createItemForm)))
            .andExpect(status().isCreated());

  public static String asJsonString(final Object obj) {
    try {
        return new ObjectMapper().writeValueAsString(obj);
    } catch (Exception e) {
        throw new RuntimeException(e);
    }
}

Answer 3

The issue is that you are serializing your bean with a custom Gson object while the application is attempting to deserialize your JSON with a Jackson ObjectMapper (within MappingJackson2HttpMessageConverter).

If you open up your server logs, you should see something like

Exception in thread "main" com.fasterxml.jackson.databind.exc.InvalidFormatException: Can not construct instance of java.util.Date from String value '2013-34-10-10:34:31': not a valid representation (error: Failed to parse Date value '2013-34-10-10:34:31': Can not parse date "2013-34-10-10:34:31": not compatible with any of standard forms ("yyyy-MM-dd'T'HH:mm:ss.SSSZ", "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'", "EEE, dd MMM yyyy HH:mm:ss zzz", "yyyy-MM-dd"))
 at [Source: java.io.StringReader@baea1ed; line: 1, column: 20] (through reference chain: com.spring.Bean["publicationDate"])

among other stack traces.

One solution is to set your Gson date format to one of the above (in the stacktrace).

The alternative is to register your own MappingJackson2HttpMessageConverter by configuring your own ObjectMapper to have the same date format as your Gson.