[스프링 부트] chapter 38. 스프링 REST 클라이언트 1부 RestTemplate과 WebClient

18 Jun 2021

springboot

스프링 REST 클라이언트 1부 RestTemplate과 WebClient

RestTemplate

Blocking I/O 기반과 Synchronous API
RestTemplateAutoConfiguration
프로젝트에 spring-web 모듈이 있다면 RestTemplateBuilder를 빈으로 등록해 줍니다.
https://docs.spring.io/spring/docs/current/spring-framework-reference/integration.html#rest-client-access

@Component
public class RestRunner implements ApplicationRunner {

    @Autowired
    RestTemplateBuilder restTemplateBuilder;

    @Override
    public void run(ApplicationArguments args) throws Exception {
        RestTemplate restTemplate = restTemplateBuilder.build();

        StopWatch stopWatch = new StopWatch();
        stopWatch.start();

        String helloResult = restTemplate.getForObject("http://localhost:8080/hello", String.class);
        System.out.println(helloResult);

        String worldResult = restTemplate.getForObject("http://localhost:8080/world", String.class);
        System.out.println(worldResult);

        stopWatch.stop();
        System.out.println(stopWatch.prettyPrint());
    }
}

WebClient

Non-Blocking I/O 기반의 Asynchronous API
WebClientAutoConfiguration
프로젝트에 spring-webflux 모듈이 있다면 WebClient.Builder를 빈으로 등록해 줍니다.
https://docs.spring.io/spring/docs/current/spring-framework-reference/web-reactive.html#webflux-client

@Component
public class RestRunner implements ApplicationRunner {

    @Autowired
    WebClient.Builder builder;

    @Override
    public void run(ApplicationArguments args) throws Exception {
        WebClient webClient = builder.build();

        StopWatch stopWatch = new StopWatch();
        stopWatch.start();

        Mono<String> helloMono = webClient.get().uri("http://localhost:8080/hello")
                .retrieve()
                .bodyToMono(String.class);
        helloMono.subscribe(s -> {
            System.out.println(s);

            if(stopWatch.isRunning()) {
                stopWatch.stop();
            }

            System.out.println(stopWatch.prettyPrint());
            stopWatch.start();
        });

        Mono<String> worldMono = webClient.get().uri("http://localhost:8080/world")
                .retrieve()
                .bodyToMono(String.class);
        worldMono.subscribe(s -> {
            System.out.println(s);

            if(stopWatch.isRunning()) {
                stopWatch.stop();
            }

            System.out.println(stopWatch.prettyPrint());
            stopWatch.start();
        });

        stopWatch.stop();
        System.out.println(stopWatch.prettyPrint());
    }
}