다른 서버에 REST요청하기

다른 서버에 REST요청하기

build.gradle

implementation 'org.apache.httpcomponents:httpclient:4.5'

implementation 'com.google.code.gson:gson:2.8.5'

이 경우 spring이 client와 같은 역할이 되므로 위의 라이브러리를 설치.

application.yml

restTemplate:
  factory:
    readTimeout: 5000
    connectTimeout: 3000
  httpClient:
    maxConnTotal: 100
    maxConnPerRoute: 5

RestfulCofig 클래스

import org.apache.http.client.HttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
import org.springframework.web.client.RestTemplate;




/**
 * 다른 서버에 Rest요청을 할 때 필요한 설정을 해주는 클래스
 */

@Configuration
public class RestfulConfig {

    @Value("${restTemplate.factory.readTimeout}")
    private int READ_TIMEOUT;

    @Value("${restTemplate.factory.connectTimeout}")
    private int CONNECT_TIMEOUT;

    @Value("${restTemplate.httpClient.maxConnTotal}")
    private int MAX_CONN_TOTAL;

    @Value("${restTemplate.httpClient.maxConnPerRoute}")
    private int MAX_CONN_PER_ROUTE;

    @Bean
    public RestTemplate restTemplate() {

        HttpComponentsClientHttpRequestFactory factory = new HttpComponentsClientHttpRequestFactory();
        factory.setReadTimeout(READ_TIMEOUT);
        factory.setConnectTimeout(CONNECT_TIMEOUT);

        HttpClient httpClient = HttpClientBuilder.create()
                .setMaxConnTotal(MAX_CONN_TOTAL)
                .setMaxConnPerRoute(MAX_CONN_PER_ROUTE)
                .build();

        factory.setHttpClient(httpClient);
        RestTemplate restTemplate = new RestTemplate(factory);

        return restTemplate;
    }
}

사용하는 부분

public String Request(){


    String jsonStr = restTemplate.getForObject("http://172.27.106.250/", String.class);

    Gson gson = new Gson();
    List<CurrentVO> list = gson.fromJson(jsonStr, new TypeToken<List<CurrentVO>>(){}.getType());

    return "리스트에서 10번째의 값: "+ list.get(10).value;


}

Request 참고: https://4urdev.tistory.com/58

JSON 리스트를 객채로 파싱 참고: https://jekalmin.tistory.com/entry/Gson%EC%9D%84-%EC%9D%B4%EC%9A%A9%ED%95%9C-json%EC%9D%84-%EA%B0%9D%EC%B2%B4%EC%97%90-%EB%8B%B4%EA%B8%B0