HttpClient Fluent API 高并发优化

apache的httpcomponents-client 4.2之后提供了一套易于使用的facade API称为Fluent API，对于一般使用场景来说，使用起来非常简便，且性能也有一定保证，因为其内部使用了连接池技术，但是在一些具体项目调优过程中也需要对其进行优化和定制。

先上代码：

package com.wangan.utils;

import java.io.IOException;
import java.security.KeyManagementException;
import java.security.NoSuchAlgorithmException;

import javax.net.ssl.SSLContext;

import org.apache.http.client.HttpClient;
import org.apache.http.client.fluent.Executor;
import org.apache.http.client.fluent.Request;
import org.apache.http.config.Registry;
import org.apache.http.config.RegistryBuilder;
import org.apache.http.conn.socket.ConnectionSocketFactory;
import org.apache.http.conn.socket.LayeredConnectionSocketFactory;
import org.apache.http.conn.socket.PlainConnectionSocketFactory;
import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
import org.apache.http.conn.ssl.SSLInitializationException;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * httpclient fluent工具类
 */
public class HttpFluentUtil {
    private Logger logger = LoggerFactory.getLogger(HttpFluentUtil.class);
    private final static int MaxPerRoute = 200;
    private final static int MaxTotal = 400;
    final static PoolingHttpClientConnectionManager CONNMGR;
    final static HttpClient CLIENT;
    final static Executor executor;

    static {
        LayeredConnectionSocketFactory ssl = null;
        try {
            ssl = SSLConnectionSocketFactory.getSystemSocketFactory();
        } catch (final SSLInitializationException ex) {
            final SSLContext sslcontext;
            try {
                sslcontext = SSLContext.getInstance(SSLConnectionSocketFactory.TLS);
                sslcontext.init(null, null, null);
                ssl = new SSLConnectionSocketFactory(sslcontext);
            } catch (final SecurityException ignore) {
            } catch (final KeyManagementException ignore) {
            } catch (final NoSuchAlgorithmException ignore) {
            }
        }

        final Registry<ConnectionSocketFactory> sfr = RegistryBuilder.<ConnectionSocketFactory>create()
                .register("http", PlainConnectionSocketFactory.getSocketFactory())
                .register("https", ssl != null ? ssl : SSLConnectionSocketFactory.getSocketFactory()).build();

        CONNMGR = new PoolingHttpClientConnectionManager(sfr);
        CONNMGR.setDefaultMaxPerRoute(MaxPerRoute);
        CONNMGR.setMaxTotal(MaxTotal);
        CLIENT = HttpClientBuilder.create().setConnectionManager(CONNMGR).build();
        executor = Executor.newInstance(CLIENT);
    }

    public static String Get(String uri, int connectTimeout, int socketTimeout) throws IOException {
        return executor.execute(Request.Get(uri).connectTimeout(connectTimeout).socketTimeout(socketTimeout))
                .returnContent().asString();
    }

    public static String Post(String uri, StringEntity stringEntity, int connectTimeout, int socketTimeout)
            throws IOException {
        return executor.execute(Request.Post(uri).socketTimeout(socketTimeout)
                .addHeader("Content-Type", "application/json").body(stringEntity)).returnContent().asString();
    }

    public static void main(String[] args) {
        HttpUtil httpUtil = new HttpUtil();
        String url = "http://localhost:9064/portal/app/test"; // 服务端sleep5秒再返回

        for (int i = 0; i < 5; i++) { // MaxPerRoute若设置为2，则5线程分3组返回（2、2、1），共15秒
            new Thread(new Runnable() {
                @Override
                public void run() {
                    try {
                        String result = HttpFluentUtil.Get(url, 2000, 2000);
                        System.out.println(result);
                    } catch (IOException e) {
                        e.printStackTrace();
                    }

                }
            }).start();
        }

    }
}

在原org.apache.http.client.fluent包下Executor中MaxPerRoute代表同一路由下最大连接数，MaxTotal总最大连接数，默认值分别为100，200.

在HttpFluentUtil中我们分别将这两个数字设置为2、4，然后启动5个线程去访问服务端，服务端设置sleep(5000)，执行上述程序，5线程分3组每隔5秒（2、2、1）返回了结果，

调整MaxPerRoute、MaxTotal为（100、200）后，5线程在5秒后同时返回了结果。

在实际项目中，默认的MaxPerRoute=100、MaxTotal=200依然会出现瓶颈的情况，可根据实际情况进行调整。