HttpClient工具正确使用方式

迈不过友情╰ 2021-06-24 15:58 581阅读 0赞

虽然现在基于netty和thift的微服务非常的流行，但是公司内部的蛮多系统仍然对外提供http接口。在调用http接口工具类中，apache httpclient工具用的比较多。下面列举一些正确使用httpclient的一些要点。  
设置socketTimeout  
可以在RequestConfig 中设置socketTimeout，表示数据传输处理时间，如下：  
  
  
 RequestConfig requestConfig = RequestConfig.custom().setSocketTimeout(4000).build()  
设置connectionRequestTimeout  
  
  
可以在RequestConfig 中设置socketTimeout，表示从连接池中后去连接的timeout时间，如下：  
RequestConfig requestConfig = RequestConfig.custom().setConnectionRequestTimeout(1000)  
设置connectTimeout  
  
可以在RequestConfig 中设置connectTimeout，表示建立连接的timeout时间，如下：  
  
RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(3000).build();  
设置MaxTotal  
  
MaxTotal表示连接池最大并发连接数，代码如下：  
  
PoolingHttpClientConnectionManager pccm = new PoolingHttpClientConnectionManager();  
    pccm.setMaxTotal(300);   
设置DefaultMaxPerRout  
  
DefaultMaxPerRout表示单路由的最大并发连接数，假设你的业务系统需要调用A和B这两个外部系统的http接口，那么如果DefaultMaxPerRout=100，那么调用A系统的http接口时，最大并发数就是100。代码如下：  
  
PoolingHttpClientConnectionManager pccm = new PoolingHttpClientConnectionManager();  
    pccm.setDefaultMaxPerRoute(100); // 单路由最大并发数  
尽量不要设置超时重试次数

如果要设置的话，可以如下设置：

// 设置默认时间 
        RequestConfig params = RequestConfig.custom().setConnectTimeout(3000).setConnectionRequestTimeout(1000).setSocketTimeout(4000)
            .setExpectContinueEnabled(true).build();
    
        PoolingHttpClientConnectionManager pccm = new PoolingHttpClientConnectionManager();
        pccm.setMaxTotal(300); // 连接池最大并发连接数
        pccm.setDefaultMaxPerRoute(50); // 单路由最大并发数
    HttpRequestRetryHandler retryHandler = new HttpRequestRetryHandler() {
          public boolean retryRequest(IOException exception , int executionCount , HttpContext context) {
            if (executionCount > 3) {
              return false;
            }
            if (exception instanceof NoHttpResponseException) {
              LOGGER.info(
                  "[NoHttpResponseException has retry request:" + context.toString() + "][executionCount:" + executionCount + "]");
              return true;
            }
            else if (exception instanceof SocketException) {
              LOGGER.info("[SocketException has retry request:" + context.toString() + "][executionCount:" + executionCount + "]");
              return true;
            }
            return false;
          }
        };
        httpclient = HttpClients.custom().setConnectionManager(pccm).setDefaultRequestConfig(params).setRetryHandler(retryHandler)
            .build();

**注：看源码得知，默认是不会重发的  
Assigns org.apache.http.client.HttpRequestRetryHandler instance.  
Please note this value can be overridden by the disableAutomaticRetries() method.   
//Disables automatic request recovery and re-execution.  
public final HttpClientBuilder disableAutomaticRetries() \{  
automaticRetriesDisabled = true;  
return this;  
\}**

完整：、

package test;
    
    import java.io.IOException;
    import java.io.UnsupportedEncodingException;
    import java.net.SocketException;
    import java.util.ArrayList;
    import java.util.List;
    import java.util.Map;
    import java.util.Map.Entry;
    
    import org.apache.http.HttpEntity;
    import org.apache.http.HttpStatus;
    import org.apache.http.NameValuePair;
    import org.apache.http.NoHttpResponseException;
    import org.apache.http.client.HttpRequestRetryHandler;
    import org.apache.http.client.config.RequestConfig;
    import org.apache.http.client.entity.UrlEncodedFormEntity;
    import org.apache.http.client.methods.CloseableHttpResponse;
    import org.apache.http.client.methods.HttpPost;
    import org.apache.http.client.methods.HttpUriRequest;
    import org.apache.http.impl.client.CloseableHttpClient;
    import org.apache.http.impl.client.HttpClients;
    import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
    import org.apache.http.message.BasicNameValuePair;
    import org.apache.http.protocol.HttpContext;
    import org.apache.http.util.EntityUtils;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    
    import com.alibaba.fastjson.JSON;
    
    public class HttpClientUtils {
      private final static Logger LOGGER = LoggerFactory.getLogger(HttpClientUtils.class);
    
      private final static String UTF8 = "UTF-8";
    
      public static CloseableHttpClient httpclient = null;
    
      static {
        // 初始化线程池
        RequestConfig params = RequestConfig.custom().setConnectTimeout(3000).setConnectionRequestTimeout(1000).setSocketTimeout(4000)
            .setExpectContinueEnabled(true).build();
    
        PoolingHttpClientConnectionManager pccm = new PoolingHttpClientConnectionManager();
        pccm.setMaxTotal(300); // 连接池最大并发连接数
        pccm.setDefaultMaxPerRoute(50); // 单路由最大并发数
    
        HttpRequestRetryHandler retryHandler = new HttpRequestRetryHandler() {
          public boolean retryRequest(IOException exception , int executionCount , HttpContext context) {
            // 重试1次,从1开始
            if (executionCount > 1) {
              return false;
            }
            if (exception instanceof NoHttpResponseException) {
              LOGGER.info(
                  "[NoHttpResponseException has retry request:" + context.toString() + "][executionCount:" + executionCount + "]");
              return true;
            }
            else if (exception instanceof SocketException) {
              LOGGER.info("[SocketException has retry request:" + context.toString() + "][executionCount:" + executionCount + "]");
              return true;
            }
            return false;
          }
        };
        httpclient = HttpClients.custom().setConnectionManager(pccm).setDefaultRequestConfig(params).setRetryHandler(retryHandler)
            .build();
      }
    
      public static String post(String urlToRequest , Map<String, Object> parameters , Integer connectionRequestTimeout ,
          Integer connectTimeout , Integer socketTimeout) {
    
        Long startTs = System.currentTimeMillis();
        List<NameValuePair> nvps = new ArrayList<NameValuePair>();
    
        if (parameters != null && !parameters.isEmpty()) {
          for (Entry<String, Object> entry : parameters.entrySet()) {
            nvps.add(new BasicNameValuePair(entry.getKey(), String.valueOf(entry.getValue())));
          }
        }
    
        try {
          LOGGER.info("post-req:url:{},param:{}", urlToRequest, JSON.toJSONString(parameters));
          HttpPost post = new HttpPost(urlToRequest);
    
          if (connectionRequestTimeout != null && connectTimeout != null && socketTimeout != null) {
            RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(connectTimeout)
                .setConnectionRequestTimeout(connectionRequestTimeout).setSocketTimeout(socketTimeout).build();
            post.setConfig(requestConfig);
          }
          post.setEntity(new UrlEncodedFormEntity(nvps, UTF8));
    
          String result = invoke(post);
          Long endTs = System.currentTimeMillis();
          Long currentMethodCallTime = endTs - startTs;
          if (currentMethodCallTime > 5000) {
            LOGGER.warn("url:{},call time {} ms", urlToRequest, currentMethodCallTime);
            LOGGER.info("所有存活线程="+Thread.getAllStackTraces().size());
          }
          LOGGER.info("post-rps:{}", result);
          return result;
        }
        catch (UnsupportedEncodingException e) {
          LOGGER.error("[HttpClientUtils][post][Unsupported Encoding Exception]", e);
        }
        return null;
      }
    
      private static String invoke(HttpUriRequest request) {
        CloseableHttpResponse response = null;
        try {
          response = httpclient.execute(request);
          if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
            HttpEntity entity = response.getEntity();
            return EntityUtils.toString(entity, UTF8);
          }
        }
        catch (IOException e) {
          LOGGER.error(
              "[HttpClientUtils][invoke][method:" + request.getMethod() + " URI:" + request.getURI() + "] is request exception", e);
        }
        finally {
          if (response != null) {
            try {
              response.close();
            }
            catch (IOException e) {
              LOGGER.error(
                  "[HttpClientUtils][invoke][method:" + request.getMethod() + " URI:" + request.getURI() + "] is closed exception",
                  e);
            }
          }
        }
        return null;
      }
    }