RestTemplate Interceptor

HandlerInterceptorAdapter is an implementation that applies to @Controller or @RestController. Not an implementation for RestTemplete.

To apply it to RestTemplete, you need to use ClientHttpRequestInterceptor.

ex.

@Component public class CustomInterceptor implements ClientHttpRequestInterceptor { @Override public ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution) throws IOException { // ... } } 

@Configuation public class RestTempleteConfig { // ... @Autowired private CustomInterceptor customInterceptor; @Bean public RestTemplate restTemplate(){ RestTemplate template = new RestTemplate(); List<ClientHttpRequestInterceptor> interceptors = new ArrayList<>(); template.add(customInterceptor); return template; } } 

The HandlerInterceptorAdapter is for the server side (i.e. RestController) to intercept some important events when server processes a HTTP request , it is nothing to do with what HTTP client (e.g RestTemplate) is used.

If you want to use RestTemplate as a HTTP client and want to intercept the request just before it sent out and the response just after it received , you must use ClientHttpRequestInterceptor.

I’m trying to intercept requests and responses in a more flexible way than ClientHttpRequestInterceptor.

From your comment above , what is your actual use-cases that it cannot handle ? I think ClientHttpRequestInterceptor is already quite flexible enough to implement any complex logic to intercept request and response. As your question does not provide any information about how you need to intercept , I can only give a general example to show what the ClientHttpRequestInterceptor can offer .

To configure the RestTemplate to use an interceptor :

RestTemplate rt = new RestTemplate(); List<ClientHttpRequestInterceptor> interceptors= new ArrayList<ClientHttpRequestInterceptor>(); inteceptors.add(new MyClientHttpRequestInterceptor()); 

And the ClientHttpRequestInterceptor looks like:

public class MyClientHttpRequestInterceptor implements ClientHttpRequestInterceptor{ @Override public ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution) throws IOException { //The HTTP request and its body are intercepted here which you can log them or modify them. e.g. System.out.println("Log the HTTP request header: " + request.getHeaders()); //Modify the HTTP request header.... request.getHeaders().add("foo", "fooValue"); //Throw exception if you do not want to send the HTTP request //If it is at the end of the interceptor chain , call execution.execute() to confirm sending the HTTP request will return the response in ClientHttpResponse //Otherwise, it will pass the request to the next interceptor in the chain to process ClientHttpResponse response= execution.execute(request, body); //The HTTP response is intercepted here which you can log them or modify them.e.g. System.out.println("Log the HTTP response header: " + response.getHeaders()); //Modify the HTTP response header response.getHeaders().add("bar", "barValue"); return response; } } 

Please note that you can also configure a chain of ClientHttpRequestInterceptor which allows to split some complex request and response intercept logic into many smalls and reusable ClientHttpRequestInterceptor. It is designed with the Chain of responsibility design pattern which its API experience is very similar to what Filter#doFilter() in Servlet.

As @WonChulHeo noted you can't use HandlerInterceptorAdapter with RestTemplate. Only ClientHttpRequestInterceptor. It's not clear why do you need exactly HandlerInterceptorAdapter - we can only see that you are trying to log the fact of the request interception. And ClientHttpRequestInterceptor is absolutely able to do the same and even more - check my working example bellow.

P.S. There is an error in your code - you can't use private access for @Bean methods - check your private RestTemplate restTemplate() { please...

@Slf4j @RestController @SpringBootApplication public class Application { public static void main(String[] args) { new SpringApplicationBuilder(Application.class) .bannerMode(Banner.Mode.OFF) .run(args); } @GetMapping("/users/{id}") public User get(@PathVariable int id) { log.info("[i] Controller: received request GET /users/{}", id); return new User(id, "John Smith"); } @Bean public RestTemplate restTemplate(RestTemplateBuilder templateBuilder) { ClientHttpRequestFactory requestFactory = new BufferingClientHttpRequestFactory(new SimpleClientHttpRequestFactory()); return templateBuilder .interceptors((request, bytes, execution) -> { URI uri = request.getURI(); HttpMethod method = request.getMethod(); log.info("[i] Interceptor: requested {} {}", method, uri); log.info("[i] Interceptor: request headers {}", request.getHeaders()); ClientHttpRequest delegate = requestFactory.createRequest(uri, method); request.getHeaders().forEach((header, values) -> delegate.getHeaders().put(header, values)); ClientHttpResponse response = delegate.execute(); log.info("[i] Interceptor: response status: {}", response.getStatusCode().name()); log.info("[i] Interceptor: response headers: {}", response.getHeaders()); String body = StreamUtils.copyToString(response.getBody(), Charset.defaultCharset()); log.info("[i] Interceptor: response body: '{}'", body); return response; }) .rootUri("http://localhost:8080") .build(); } @Bean ApplicationRunner run(RestTemplate restTemplate) { return args -> { ResponseEntity<User> response = restTemplate.getForEntity("/users/{id}", User.class, 1); if (response.getStatusCode().is2xxSuccessful()) { log.info("[i] User: {}", response.getBody()); } else { log.error("[!] Error: {}", response.getStatusCode()); } }; } } 

@Data @AllArgsConstructor @NoArgsConstructor public class User { private int id; private String name; }