Httpclient 多线程调用，高效配置

最近公司通过API接口调用数据，本人搞了多线程调用。起初每次调用都单独 new HttpClient(),造成问题是内存越跑占用越大，请求越来越慢，甚至出现 Read Time Out 异常。

之后了解HttpClient可复用，则改为单例请求，加入配置设置问题解决。注：本人用的httpclient-4.3.6.jar

（1）创建HttpClient

CloseableHttpClient client=HttpClientUtil.getHttpClient();

HttpclientUtil 用的连接池的概念,当请求结束并不是直接断开连接,而是返回给连接池方便下次调用。

public class HttpClientUtil {
    private static Logger LOGGER = LoggerFactory.getLogger(HttpClientUtil.class);
    private static PoolingHttpClientConnectionManager cm = null;

    static {
        LayeredConnectionSocketFactory sslsf = null;
        try {
            sslsf = new SSLConnectionSocketFactory(SSLContext.getDefault());
        } catch (NoSuchAlgorithmException e) {
            LOGGER.error("创建SSL连接失败");
        }
        Registry socketFactoryRegistry = RegistryBuilder.create()
                .register("https", sslsf)
                .register("http", new PlainConnectionSocketFactory())
                .build();
        cm =new PoolingHttpClientConnectionManager(socketFactoryRegistry);
        cm.setMaxTotal(200);//多线程调用注意配置，根据线程数设定
        cm.setDefaultMaxPerRoute(300);//多线程调用注意配置，根据线程数设定

    }

    public static CloseableHttpClient getHttpClient() {
        CloseableHttpClient httpClient = HttpClients.custom()
                .setConnectionManager(cm)
                .build();
        return httpClient;
    }
}

此处则创建httpclient 成功，下一注意点为 RequestConfig 参数配置，此处配置直接影响调用接口返回速度及是否 出现 Read time out 异常。

CloseableHttpClient client=HttpClientUtil.getHttpClient();

HttpclientUtil 用的连接池的概念,当请求结束并不是直接断开连接,而是返回给连接池方便下次调用。

public class HttpClientUtil {
    private static Logger LOGGER = LoggerFactory.getLogger(HttpClientUtil.class);
    private static PoolingHttpClientConnectionManager cm = null;

    static {
        LayeredConnectionSocketFactory sslsf = null;
        try {
            sslsf = new SSLConnectionSocketFactory(SSLContext.getDefault());
        } catch (NoSuchAlgorithmException e) {
            LOGGER.error("创建SSL连接失败");
        }
        Registry socketFactoryRegistry = RegistryBuilder.create()
                .register("https", sslsf)
                .register("http", new PlainConnectionSocketFactory())
                .build();
        cm =new PoolingHttpClientConnectionManager(socketFactoryRegistry);
        cm.setMaxTotal(200);//多线程调用注意配置，根据线程数设定
        cm.setDefaultMaxPerRoute(300);//多线程调用注意配置，根据线程数设定

    }

    public static CloseableHttpClient getHttpClient() {
        CloseableHttpClient httpClient = HttpClients.custom()
                .setConnectionManager(cm)
                .build();
        return httpClient;
    }
}

此处则创建httpclient 成功，下一注意点为 RequestConfig 参数配置，此处配置直接影响调用接口返回速度及是否 出现 Read time out 异常。

（2）参数配置

CloseableHttpClient client=HttpClientUtil.getHttpClient();
// 发送get请求
HttpGet request = new HttpGet(url);
CloseableHttpResponse response=null;
// 设置请求和传输超时时间

RequestConfig requestConfig = RequestConfig.custom()
      .setSocketTimeout(20000)//数据传输过程中数据包之间间隔的最大时间
      .setConnectTimeout(20000)//连接建立时间，三次握手完成时间
      .setExpectContinueEnabled(true)//重点参数 
      .setConnectionRequestTimeout(10000)
      .setStaleConnectionCheckEnabled(true)//重点参数，在请求之前校验链接是否有效
      .build();
request.setConfig(requestConfig);
try {
   response = client.execute(request);
   if(response.getStatusLine().getStatusCode() != HttpStatus.SC_OK) {
      System.out.println("请求失败");
      return  null;

   }
   HttpEntity resEntity =  response.getEntity();
   if(resEntity==null){
         return  null;
   }
   String result=EntityUtils.toString(resEntity, "UTF-8");
   return result;
} catch (UnsupportedEncodingException e) {
   System.out.println(e.getMessage());
   return null;
} catch (ClientProtocolException e) {
   System.out.println(e.getMessage());
   return null;
} catch (IOException e) {
   System.out.println(e.getMessage());
}finally {
   if(response != null)
   {
      try {

//此处调优重点，多线程模式下可提高性能。
         EntityUtils.consume(response.getEntity());//此处高能，通过源码分析，由EntityUtils是否回收HttpEntity

         response.close();
      } catch (IOException e) {
         System.out.println("关闭response失败:"+ e);
      }
}
}

此配置，经过2周观察，暂时是最高效的，感觉网上大牛写的不一定是最适合你的，自己多调试，配置出属于自己最高效的。