Using RestTemplate for POST Requests in Spring Boot

In Spring Boot, RestTemplate is a powerful tool to communicate with other services via RESTful APIs. It simplifies the process of sending HTTP requests and handling responses.

If you succeeded with the GET method but the POST one seems trickier, then read the code below.

I made it as simple as possible, and the comments will help you understand the process.

Notice, setting the headers and body depends on your API provider requirements.

@Component
public class RestTemplatePost implements CommandLineRunner {

    @Value("${auth.basic}")
    private String basicAuth;

    @Value("${auth.url}")
    private String authEndpoint;

    @Override
    public void run(String... args) throws Exception {

        // Setting the header
        HttpHeaders headers = new HttpHeaders();
        headers.setAccept(Arrays.asList(MediaType.APPLICATION_JSON));
        headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);
        headers.setBasicAuth(basicAuth);

        // Setting the body
        MultiValueMap<String, String> body = new LinkedMultiValueMap<>();
        body.add("key", "value");

        // Setting the request entity
        HttpEntity<MultiValueMap<String, String>> entity = new HttpEntity<>(body, headers);

        try {
            RestTemplate restTemplate = new RestTemplateBuilder().build();
            ResponseEntity<AuthData> auth = restTemplate.exchange(authEndpoint, HttpMethod.POST, entity, AuthData.class);
            // Handle result
        } catch (Exception e) {
            // Handle error
        }
    }
}

Well, happy coding 😎