Making authenticated POST requests with Spring RestTemplate for Android

Ok found the answer. exchange() is the best way. Oddly the HttpEntity class doesn't have a setBody() method (it has getBody()), but it is still possible to set the request body, via the constructor.

// Create the request body as a MultiValueMapMultiValueMap<String, String> body = new LinkedMultiValueMap<String, String>();     body.add("field", "value");// Note the body object as first parameter!HttpEntity<?> httpEntity = new HttpEntity<Object>(body, requestHeaders);ResponseEntity<MyModel> response = restTemplate.exchange("/api/url", HttpMethod.POST, httpEntity, MyModel.class);

Slightly different approach:

MultiValueMap<String, String> headers = new LinkedMultiValueMap<String, String>();headers.add("HeaderName", "value");headers.add("Content-Type", "application/json");RestTemplate restTemplate = new RestTemplate();restTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter());HttpEntity<ObjectToPass> request = new HttpEntity<ObjectToPass>(objectToPass, headers);restTemplate.postForObject(url, request, ClassWhateverYourControllerReturns.class);

I was recently dealing with an issue when I was trying to get past authentication while making a REST call from Java, and while the answers in this thread (and other threads) helped, there was still a bit of trial and error involved in getting it working.

What worked for me was encoding credentials in Base64 and adding them as Basic Authorization headers. I then added them as an HttpEntity to restTemplate.postForEntity, which gave me the response I needed.

Here's the class I wrote for this in full (extending RestTemplate):

public class AuthorizedRestTemplate extends RestTemplate{    private String username;    private String password;    public AuthorizedRestTemplate(String username, String password){        this.username = username;        this.password = password;    }    public String getForObject(String url, Object... urlVariables){        return authorizedRestCall(this, url, urlVariables);    }    private String authorizedRestCall(RestTemplate restTemplate,             String url, Object... urlVariables){        HttpEntity<String> request = getRequest();        ResponseEntity<String> entity = restTemplate.postForEntity(url,                 request, String.class, urlVariables);        return entity.getBody();    }    private HttpEntity<String> getRequest(){        HttpHeaders headers = new HttpHeaders();        headers.add("Authorization", "Basic " + getBase64Credentials());        return new HttpEntity<String>(headers);    }    private String getBase64Credentials(){        String plainCreds = username + ":" + password;        byte[] plainCredsBytes = plainCreds.getBytes();        byte[] base64CredsBytes = Base64.encodeBase64(plainCredsBytes);        return new String(base64CredsBytes);    }}