RestTemplate / WebClient

RestTemplate

1. RestTemplate : 블로킹 I/O 기반 동기 API
2. RestTemplateAutoConfiguration
3. 프로젝트 spring-web 모듈 존재시 RestTemplateBuilder를 빈으로 등록함

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WebClient

1. 논 블로킹 I/O 기반 비동기 API
2. WebClientAutoConfiguration
3. 프로젝트 spring-webflux 모듈 존재시 WebClient.Builder 빈을 등록해 줌

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결과 적으로 동기, 비동기에 따라

RestTemplateBuilder , WebClient.Builder 를 사용해서 객체를 빌딩하여 사용하게 된다. 빌더 패턴이므로 체인 api 도 존재함

 

@RestController
public class SampleController {

    @GetMapping("/hello")
    public String hello() throws InterruptedException {
        Thread.sleep(5000l);
        return "hello";
    }

    @GetMapping("/world")
    public String world() throws InterruptedException {
        Thread.sleep(5000l);
        return "world";
    }
}

 

@Component
public class RestRunner implements ApplicationRunner {

    @Autowired
    private RestTemplateBuilder restTemplateBuilder;

    @Override
    public void run(ApplicationArguments args) throws Exception {

        RestTemplate restTemplate = restTemplateBuilder.build();

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

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

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


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


hello
world
StopWatch '': running time = 10241013100 ns
---------------------------------------------
ns         %     Task name
---------------------------------------------
10241013100  100%  

---

@Component
public class NoneBlockingRestRunner implements ApplicationRunner {

    @Autowired
    private WebClient.Builder builder;
    @Override
    public void run(ApplicationArguments args) throws Exception {

        WebClient webClient = builder.build();

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

        // stream api
        Mono<String> helloMono = webClient.get().uri("http://localhost:8080/hello").retrieve().bodyToMono(String.class);
        // stream 동작
        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( f -> {
            System.out.println(f);
            if(stopWatch.isRunning()) {
                stopWatch.stop();
            }

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


world
hello
StopWatch '': running time = 6557595600 ns
---------------------------------------------
ns         %     Task name
---------------------------------------------
6557595600  100%  

StopWatch '': running time = 6557595600 ns
---------------------------------------------
ns         %     Task name
---------------------------------------------
6557595600  100%