TestRestTemplate.postForEntity returns 400 with No Descriptive Message - spring-boot

Question

I'm having some trouble using TestRestTemplate.postForEntity(). My code is:
#Test
public void testAdd() {
Map<String,String> mParams=new HashMap<>();
mParams.put("joke","This is my joke");
mParams.put("description","Totally Tasteless Joke");
mParams.put("date",Long.toString(System.currentTimeMillis()));
ResponseEntity<Joke> reJoke = restTemplate.postForEntity(getURLBase()+"/add",
null,
Joke.class,
mParams
);
Joke j = reJoke.getBody();
System.out.println("Status="+reJoke.getStatusCode()+" j.getJoke()="+j.getJoke()+" id="+j.getId());
}
The returned Status value is 400. Nothing is printed on the console.
I have a testGet() that does work:
#Test
public void testGet() {
System.out.println("testGet()");
initData();
ResponseEntity<Joke> reJoke=restTemplate.getForEntity(getURLBase()+"/1",Joke.class,new HashMap<String,String>());
Joke j=reJoke.getBody();
System.out.println("Status=" + reJoke.getStatusCode()+" j =" + j + (j == null ? "" : j.getJoke()));
}
I noticed in the Javadoc for TestRestTemplate it says:
If Apache Http Client 4.3.2 or better is available (recommended) it will be used as the client, and by default configured to ignore cookies and redirects.
I've added
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>4.5.5</version>
<scope>test</scope>
</dependency>
to pom.xml, but it doesn't seem to make any difference.
Can anyone tell me how to either solve the issue, or get more information than "400"? It's really appreciated.

Answer 1

After a little searching, I found that the mParams was actually URL parameters. I needed to send the form encoded parameters as the request object. The working code is:
#Test
public void testAdd() {
MultiValueMap<String, String> mParams= new LinkedMultiValueMap<String, String>();
mParams.add("joke", "This is my joke");
mParams.add("description", "Totally Tasteless Joke");
mParams.add("date", Long.toString(System.currentTimeMillis()));
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);
HttpEntity<MultiValueMap<String, String>> request = new HttpEntity<MultiValueMap<String, String>>(mParams, headers);
ResponseEntity<Joke> reJoke = restTemplate.postForEntity(getURLBase()+"/add",
request,
Joke.class
);
Joke j = reJoke.getBody();
System.out.println("Status="+reJoke.getStatusCode()+" j.getJoke()="+j.getJoke()+" id="+j.getId());
}