Apache HttpClient

CloseableHttpClient를 생성할때 생성하려면 아래와 같이 기본 설정으로 생성할 수 있다.

- CloseableHttpClient httpClient = HttpClientBuilder.create().build();

 

기본 설정으로 HttpClient를 생성할 경우, 기본값이 아래와 같기 때문에 performance가 않나올 수 있다.

- this.pool = new CPool(new InternalConnectionFactory(this.configData, connFactory), 2, 20, timeToLive, tunit);

 

때문에 아래 예제 코드와 같이 사용자가 설정을 직접 정의하여 HttpClient를 생성하는것도 고려해야 한다.

 

import lombok.extern.slf4j.Slf4j;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
import org.apache.http.util.EntityUtils;
import java.io.IOException;

@Slf4j
public class CustomHttpExecutor {
	
    private final CloseableHttpClient httpClient;

	public CustomHttpExecutor(RequestConfig requestConfig) {
		this.httpClient = createDefaultHttpClient(requestConfig, defaultConnectionManager());
	}

	private static CloseableHttpClient createDefaultHttpClient(RequestConfig requestConfig, PoolingHttpClientConnectionManager connectionManager) {
    	return HttpClientBuilder.create()
			.setDefaultRequestConfig(requestConfig)
			.setConnectionManager(connectionManager)
			.build();
	}

	private PoolingHttpClientConnectionManager defaultConnectionManager() {
		PoolingHttpClientConnectionManager connectionManager = new PoolingHttpClientConnectionManager();
			connectionManager.setMaxTotal(100);
			connectionManager.setDefaultMaxPerRoute(50);

		return cm;
	}

	public String getForString(String url) throws IOException {
		HttpGet request = new HttpGet(url);

		try (CloseableHttpResponse response = httpClient.execute(request)) {
			int httpStatus = response.getStatusLine().getStatusCode();
			String responseBody = EntityUtils.toString(response.getEntity());

			log.debug("Http get is success. : url({}), httpStatus({}, {}), responseBody({})", 
			url, response.getStatusLine().getReasonPhrase(), httpStatus, responseBody);

			response.close();

			return responseBody;
		} catch (IOException e) {
			log.warn("Http get is failed. : url({})", url);
			throw e;
		}
	}
}

Apache의 httpClient는 Spring의 RestClient와 함께 사용될 수 있다.

import org.apache.http.client.config.CookieSpecs;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
import org.springframework.web.client.RestTemplate;


private RestTemplate getRestTemplate() {

	CloseableHttpClient httpClient = HttpClientBuilder.create()
		.setConnectionManager(poolingHttpClientConnectionManager)
		.setDefaultRequestConfig(RequestConfig.custom()
			.setConnectionRequestTimeout(200)
			.setConnectTimeout(200)
			.setSocketTimeout(200)
			.setCookieSpec(CookieSpecs.IGNORE_COOKIES)
			.build())
		.build();

	HttpComponentsClientHttpRequestFactory factory = new HttpComponentsClientHttpRequestFactory();
	PoolingHttpClientConnectionManager poolingHttpClientConnectionManager = new PoolingHttpClientConnectionManager();
	poolingHttpClientConnectionManager.setDefaultMaxPerRoute(50);
	poolingHttpClientConnectionManager.setMaxTotal(100);
    
	factory.setHttpClient(httpClient);

	return new RestTemplate(factory);
}

 

** 주요 설정 :

- MaxTotal은 HttpClient에서 사용하는 전체 Thread 수 이다.
- Route는 URL Domain으로 구분된다.

- MaxPerRoute는 URL Domain별로 사용될 수 있는 최대 Thread 수 이다. 
- 전체 MaxPerRoute 수가 MaxTotal을 초과하면 각 Route는 MaxTotal 내에서 경쟁한다.

 

example)

Total Max Thread = 100

-------------------------------------

Route1 (www.naver.com/...)     50

-------------------------------------

Route2 (www.daum.com/...)     50

-------------------------------------

Route3 (www.coupang.com/...) 50

----------------------------​---------

 

** 성능개선 참고 사이트 : 

- http://hc.apache.org/httpclient-3.x/performance.html#Reuse_of_HttpClient_instance