GET Request Works in Postman but not with RestTemplate - SpringBoot

Question

I have a request that is working fine when I try to send through postman. I was trying to implement the same using code where I faced an error.

The code i am using -

RestTemplate restTemplate = new RestTemplate(); HttpHeaders headers = new HttpHeaders(); headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED); MultiValueMap<String, String> map= new LinkedMultiValueMap<String, String>(); map.add("client_id", clientid); map.add("client_secret",clientsecret); HttpEntity<?> request = new HttpEntity<>(map, headers); logger.info(request.toString()); UriComponentsBuilder builder = UriComponentsBuilder.fromHttpUrl(access_token_url) .queryParam("grant_type", "client_credentials"); logger.info("URI -" + builder.toUriString()); ResponseEntity<String> response = restTemplate.exchange(builder.build().encode().toUri(), HttpMethod.GET, request, String.class); logger.info("Response" + response.getBody());

The error I am getting is -

org.springframework.web.client.HttpClientErrorException$Unauthorized: 401 Unauthorized

But the same works in POSTMAN with the same details.

Something I want to specify

The back-end API is not in my hands.
The clientid, clientsecret, access_token_url are fetched from properties file and are correct I have cross checked them.
It is a GET request with x-www-form-urlencoded data. I checked it multiple times it is not POST
There is no Authorization such as Basic Auth as it is not set in POSTMAN itself
Went through This This and This nothing helped.

My main concern is I have never seen anywhere sending a GET request with method body, but it is working in POSTMAN and if it is working there why not in the code? Where I am going wrong?

EDIT - 1 Was marked duplicate with This but its a different error code overall. The OP got 500 Internal Server Error as he was giving wrong content type.

EDIT - 2 DEBUG Output-

2019-07-31 14:53:05.208 DEBUG 3576 --- [nio-8080-exec-1] o.s.web.client.RestTemplate : HTTP GET ORIGINAL_URL?grant_type=client_credentials 2019-07-31 14:53:05.215 DEBUG 3576 --- [nio-8080-exec-1] o.s.web.client.RestTemplate : Accept=[text/plain, application/json, application/*+json, */*] 2019-07-31 14:53:05.218 DEBUG 3576 --- [nio-8080-exec-1] o.s.web.client.RestTemplate : Writing [{client_id=[CLIENTID], client_secret=[CLIENT_SECRET]}] as "application/x-www-form-urlencoded" 2019-07-31 14:53:06.976 DEBUG 3576 --- [nio-8080-exec-1] o.s.web.client.RestTemplate : Response 401 UNAUTHORIZED 2019-07-31 14:53:07.034 DEBUG 3576 --- [nio-8080-exec-1] m.m.a.RequestResponseBodyMethodProcessor : Using 'text/html', given [text/html, application/xhtml+xml, image/webp, image/apng, application/signed-exchange;v=b3, application/xml;q=0.9, */*;q=0.8] and supported [text/plain, */*, text/plain, */*, application/json, application/*+json, application/json, application/*+json] 2019-07-31 14:53:07.035 DEBUG 3576 --- [nio-8080-exec-1] m.m.a.RequestResponseBodyMethodProcessor : Nothing to write: null body 2019-07-31 14:53:07.039 DEBUG 3576 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Completed 200 OK 2019-07-31 14:53:07.108 DEBUG 3576 --- [io-8080-exec-10] o.s.web.servlet.DispatcherServlet : GET "/favicon.ico", parameters={} 2019-07-31 14:53:07.119 DEBUG 3576 --- [io-8080-exec-10] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped to ResourceHttpRequestHandler [class path resource [META-INF/resources/], class path resource [resources/], class path resource [static/], class path resource [public/], ServletContext resource [/], class path resource []] 2019-07-31 14:53:07.181 DEBUG 3576 --- [io-8080-exec-10] o.s.web.servlet.DispatcherServlet : Completed 200 OK

Possible duplicate of REST POST works correctly with POSTMAN but exception when using Spring RestTemplate — Mebin Joe
– Mebin Joe, Commented Jul 31, 2019 at 7:15
Have you logged the spring request to see if it matches your postman request? There is some usefull class like stackoverflow.com/questions/7952154/… — Benjamin Caure
– Benjamin Caure, Commented Jul 31, 2019 at 7:17
You are telling us one way works another doesn’t. You post the code for the one that doesn’t but you don’t post the call that works. Are we supposed to guess what your API looks like so we can fix your broken code? — Toerktumlare
– Toerktumlare, Commented Jul 31, 2019 at 7:45
Here is the curl that is wokring curl -X GET \ 'URL-OF-CLIENT?grant_type=client_credentials' \ -H 'Content-Type: application/x-www-form-urlencoded' \ -d 'client_secret=SECRET&client_id=ID' — Parth Manaktala
– Parth Manaktala, Commented Jul 31, 2019 at 8:06

Eeshwar Ankathi · Accepted Answer · 2019-07-31 09:46:10Z

for the same use case, we are using the below implementation.

RestTemplate restTemplate = new RestTemplate(); HttpHeaders headers = new HttpHeaders(); headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED); headers.set("Accept", MediaType.APPLICATION_JSON_VALUE); String token = new String(Base64.getEncoder().encode((clientId + ":" + clientSecret).getBytes())); headers.add("Authorization", "Basic " + token); HttpEntity<?> request = new HttpEntity<>(headers); logger.info(request.toString()); UriComponentsBuilder builder = UriComponentsBuilder.fromHttpUrl(access_token_url).queryParam("grant_type", "client_credentials"); logger.info("URI -" + builder.toUriString()); ResponseEntity<String> response = restTemplate.exchange(builder.build().encode().toUri(), HttpMethod.POST,request, String.class); logger.info("Response" + response.getBody());

this might help you.

That works!! Thanks. Could you please explain what was my error here?
1. you were using GET, 2. you were trying to sent client Id and client secret as part of request where as we were sending them as part of Authorization Header

Toerktumlare · Accepted Answer · 2019-07-31 09:11:54Z

i suspect the following. You are double encoding your url, change:

restTemplate.exchange(builder.build().encode().toUri(), HttpMethod.GET, request, String.class);

to

restTemplate.exchange(builder.build().toUri(), HttpMethod.GET, request, String.class);

You can easy match your requests by enabling debug for spring web.

application.properties

logging.level.org.springframework.web: DEBUG

Thanks for the debug tip. I tested your solution, still its not working. It is giving me same result as before

Joel · Accepted Answer · 2023-04-25 13:03:26Z

I had a very similar issue. The problem turned out to be that there was a proxy required to access a URI outside the company. Postman had been configured to use the proxy.

Here's the code to fix this:

import java.net.InetSocketAddress; import java.net.Proxy; import org.springframework.http.client.SimpleClientHttpRequestFactory; // Initialize the REST Template with a proxy. private RestTemplate getRestTemplate(){ if(restTemplate==null) { Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress(proxyHost, proxyPort)); SimpleClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory(); requestFactory.setProxy(proxy); restTemplate = new RestTemplate(requestFactory); } return restTemplate; }

See // https://www.baeldung.com/java-resttemplate-proxy

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GET Request Works in Postman but not with RestTemplate - SpringBoot

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