java - Follow 302 redirect using Spring restTemplate?

Question

  RestTemplate restTemplate = new RestTemplate();

  final MappingJackson2XmlHttpMessageConverter converter = new MappingJackson2XmlHttpMessageConverter();
  final List<MediaType> supportedMediaTypes = new LinkedList<MediaType>(converter.getSupportedMediaTypes());
  supportedMediaTypes.add(MediaType.ALL);
  converter.setSupportedMediaTypes(supportedMediaTypes);
  restTemplate.getMessageConverters().add(converter);  


  ResponseEntity<MyDTO[]> response = restTemplate.getForEntity(urlBase, MyDTO[].class);

  HttpHeaders headers = response.getHeaders();
  URI location = headers.getLocation(); // Has my redirect URI

  response.getBody(); //Always null

I was under the impression that a 302 would automatically be followed. Am I incorrect in this assumption? I now need to pick off this location and re-request?

Answer 1

Using the default ClientHttpRequestFactory implementation - which is the SimpleClientHttpRequestFactory - the default behaviour is to follow the URL of the location header (for responses with status codes 3xx) - but only if the initial request was a GETrequest.

Details can be found in this class - searching for the following method:

protected void prepareConnection(HttpURLConnection connection, String httpMethod) throws IOException {

    ...

    if ("GET".equals(httpMethod)) {
        connection.setInstanceFollowRedirects(true);
    }

Here the relevant doc comment of HttpURLConnection.setInstanceFollowRedirects method:

Sets whether HTTP redirects (requests with response code 3xx) should be automatically followed by this {@code HttpURLConnection} instance.

The default value comes from followRedirects, which defaults to true.