HttpClien高并发请求连接池 - PoolingHttpClientConnectionManager
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连接池技术作为创建和管理连接的缓冲池技术，目前已广泛用于诸如数据库连接等长连接的维护和管理中，能够有效减少系统的响应时间，节省服务器资源开销。其优势主要有两个：其一是减少创建连接的资源开销，其二是资源的访问控制。连接池管理的对象是长连接，对于HTTP连接是否适用，我们需要首先回顾一下长连接和短连接。
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所谓长连接是指客户端与服务器端一旦建立连接以后，可以进行多次数据传输而不需重新建立连接，而短连接则每次数据传输都需要客户端和服务器端建立一次连接。长连接的优势在于省去了每次数据传输连接建立的时间开销，能够大幅度提高数据传输的速度，对于P2P应用十分适合，但是对于诸如Web网站之类的B2C应用，并发请求量大，每一个用户又不需频繁的操作的场景下，维护大量的长连接对服务器无疑是一个巨大的考验。而此时，短连接可能更加适用。但是短连接每次数据传输都需要建立连接，我们知道HTTP协议的传输层协议是TCP协议，TCP连接的建立和释放分别需要进行3次握手和4次握手，频繁的建立连接即增加了时间开销，同时频繁的创建和销毁Socket同样是对服务器端资源的浪费。所以对于需要频繁发送HTTP请求的应用，需要在客户端使用HTTP长连接。
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HTTP连接是无状态的，这样很容易给我们造成HTTP连接是短连接的错觉，实际上HTTP1.1默认即是持久连接，HTTP1.0也可以通过在请求头中设置Connection:keep-alive使得连接为长连接。既然HTTP协议支持长连接，我们就有理由相信HTTP连接同样需要连接池技术来管理和维护连接建立和销毁。HTTP Client4.0的ThreadSafeClientConnManager实现了HTTP连接的池化管理，其管理连接的基本单位是Route（路由），每个路由上都会维护一定数量的HTTP连接。这里的Route的概念可以理解为客户端机器到目标机器的一条线路，例如使用HttpClient的实现来分别请求 www.163.com 的资源和 www.sina.com 的资源就会产生两个route。缺省条件下对于每个Route，HttpClient仅维护2个连接，总数不超过20个连接，显然对于大多数应用来讲，都是不够用的，可以通过设置HTTP参数进行调整。
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两个主机建立连接的过程是很复杂的一个过程，涉及到多个数据包的交换，并且也很耗时间。Http连接需要的三次握手开销很大，这一开销对于比较小的http消息来说更大。但是如果我们直接使用已经建立好的http连接，这样花费就比较小，吞吐率更大。 传统的HttpURLConnection并不支持连接池，如果要实现连接池的机制，还需要自己来管理连接对象。对于网络请求这种底层相对复杂的操作，个人以为如果有可用的其他方案，也没有必要自己去管理连接对象。除了HttpURLConnection，大家肯定还知道HttpClient。一般情况下，普通使用HttpClient已经能满足我们的需求，不过有时候，在我们需要高并发大量的请求网络的时候，还是用“连接池”这样的概念能提升吞吐量。
我们来看下怎么使用 org.apache.httpcomponents.httpclient（版本4.4）提供的连接池来实现我们的高并发网络请求。
使用到的jar包：
org\apache\httpcomponents\httpclient\4.4-beta1\httpclient-4.4-beta1.jar
org\apache\httpcomponents\httpclient-cache\4.4-beta1\httpclient-cache-4.4-beta1.jar
org\apache\httpcomponents\httpcore\4.4-beta1\httpcore-4.4-beta1.jar
下面代码实例中主要使用到 PoolingHttpClientConnectionManager
package com.hvgroup.zhuhai10086.jms.utils;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.io.UnsupportedEncodingException;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import javax.net.ssl.SSLException;
import javax.net.ssl.SSLHandshakeException;
import org.apache.http.HttpEntity;
import org.apache.http.HttpEntityEnclosingRequest;
import org.apache.http.HttpHost;
import org.apache.http.HttpRequest;
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.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.methods.HttpRequestBase;
import org.apache.http.client.protocol.HttpClientContext;
import org.apache.http.config.Registry;
import org.apache.http.config.RegistryBuilder;
import org.apache.http.conn.ConnectTimeoutException;
import org.apache.http.conn.routing.HttpRoute;
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.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;
/**
* @Description :HttpClient工具类
* @Author : ChenYao
* @Version : 1.0
* @Create : 2019/1/13 17:11
* @Update : 2019/1/13 17:11
* @see :
*/
public class HttpClientUtil {
static final int timeOut = 10 * 1000;
private static CloseableHttpClient httpClient = null;
private final static Object syncLock = new Object();
private static void config(HttpRequestBase httpRequestBase) {
// 设置Header等
// httpRequestBase.setHeader("User-Agent", "Mozilla/5.0");
// httpRequestBase
// .setHeader("Accept",
// "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
// httpRequestBase.setHeader("Accept-Language",
// "zh-CN,zh;q=0.8,en-US;q=0.5,en;q=0.3");// "en-US,en;q=0.5");
// httpRequestBase.setHeader("Accept-Charset",
// "ISO-8859-1,utf-8,gbk,gb2312;q=0.7,*;q=0.7");
// 配置请求的超时设置
RequestConfig requestConfig = RequestConfig.custom()
.setConnectionRequestTimeout(timeOut)
.setConnectTimeout(timeOut).setSocketTimeout(timeOut).build();
httpRequestBase.setConfig(requestConfig);
}
/**
* 获取HttpClient对象
*
* @return
* @author SHANHY
* @create 2015年12月18日
*/
public static CloseableHttpClient getHttpClient(String url) {
String hostname = url.split("/")[2];
int port = 80;
if (hostname.contains(":")) {
String[] arr = hostname.split(":");
hostname = arr[0];
port = Integer.parseInt(arr[1]);
}
if (httpClient == null) {
synchronized (syncLock) {
if (httpClient == null) {
httpClient = createHttpClient(200, 40, 100, hostname, port);
}
}
}
return httpClient;
}
/**
* @Description :创建HttpClient对象
* @Author : ChenYao
* @Version : 1.0
* @Create : 2019/1/13 17:11
* @Update : 2019/1/13 17:11
* @see :
*/
public static CloseableHttpClient createHttpClient(int maxTotal,
int maxPerRoute, int maxRoute, String hostname, int port) {
ConnectionSocketFactory plainsf = PlainConnectionSocketFactory
.getSocketFactory();
LayeredConnectionSocketFactory sslsf = SSLConnectionSocketFactory
.getSocketFactory();
Registry<ConnectionSocketFactory> registry = RegistryBuilder
.<ConnectionSocketFactory> create().register("http", plainsf)
.register("https", sslsf).build();
PoolingHttpClientConnectionManager cm = new PoolingHttpClientConnectionManager(
registry);
// 将最大连接数增加
cm.setMaxTotal(maxTotal);
// 将每个路由基础的连接增加
cm.setDefaultMaxPerRoute(maxPerRoute);
HttpHost httpHost = new HttpHost(hostname, port);
// 将目标主机的最大连接数增加
cm.setMaxPerRoute(new HttpRoute(httpHost), maxRoute);
// 请求重试处理
HttpRequestRetryHandler httpRequestRetryHandler = new HttpRequestRetryHandler() {
public boolean retryRequest(IOException exception,
int executionCount, HttpContext context) {
if (executionCount >= 5) {// 如果已经重试了5次，就放弃
return false;
}
if (exception instanceof NoHttpResponseException) {// 如果服务器丢掉了连接，那么就重试
return true;
}
if (exception instanceof SSLHandshakeException) {// 不要重试SSL握手异常
return false;
}
if (exception instanceof InterruptedIOException) {// 超时
return false;
}
if (exception instanceof UnknownHostException) {// 目标服务器不可达
return false;
}
if (exception instanceof ConnectTimeoutException) {// 连接被拒绝
return false;
}
if (exception instanceof SSLException) {// SSL握手异常
return false;
}
HttpClientContext clientContext = HttpClientContext
.adapt(context);
HttpRequest request = clientContext.getRequest();
// 如果请求是幂等的，就再次尝试
if (!(request instanceof HttpEntityEnclosingRequest)) {
return true;
}
return false;
}
};
CloseableHttpClient httpClient = HttpClients.custom()
.setConnectionManager(cm)
.setRetryHandler(httpRequestRetryHandler).build();
return httpClient;
}
private static void setPostParams(HttpPost httpost,
Map<String, Object> params) {
List<NameValuePair> nvps = new ArrayList<NameValuePair>();
Set<String> keySet = params.keySet();
for (String key : keySet) {
nvps.add(new BasicNameValuePair(key, params.get(key).toString()));
}
try {
httpost.setEntity(new UrlEncodedFormEntity(nvps, "UTF-8"));
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
/**
* @Description :请求URL获取内容
* @Author : ChenYao
* @Version : 1.0
* @Create : 2019/1/13 17:11
* @Update : 2019/1/13 17:11
* @see :
*/
public static String post(String url, Map<String, Object> params) throws IOException {
HttpPost httppost = new HttpPost(url);
config(httppost);
setPostParams(httppost, params);
CloseableHttpResponse response = null;
try {
response = getHttpClient(url).execute(httppost,
HttpClientContext.create());
HttpEntity entity = response.getEntity();
String result = EntityUtils.toString(entity, "utf-8");
EntityUtils.consume(entity);
return result;
} catch (Exception e) {
// e.printStackTrace();
throw e;
} finally {
try {
if (response != null)
response.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
/**
* @Description :GET请求URL获取内容
* @Author : ChenYao
* @Version : 1.0
* @Create : 2019/1/13 17:11
* @Update : 2019/1/13 17:11
* @see :
*/
public static String get(String url) {
HttpGet httpget = new HttpGet(url);
config(httpget);
CloseableHttpResponse response = null;
try {
response = getHttpClient(url).execute(httpget,
HttpClientContext.create());
HttpEntity entity = response.getEntity();
String result = EntityUtils.toString(entity, "utf-8");
EntityUtils.consume(entity); //关闭HttpEntity是的流，如果手动关闭了InputStream instream = entity.getContent();这个流，也可以不调用这个方法
return result;
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (response != null)
response.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return null;
}
public static void main(String[] args) {
// URL列表数组
String[] urisToGet = {
"http://blog.csdn.net/catoop/article/details/38849497",
"http://blog.csdn.net/catoop/article/details/38849497",
"http://blog.csdn.net/catoop/article/details/38849497",
"http://blog.csdn.net/catoop/article/details/38849497",
"http://blog.csdn.net/catoop/article/details/38849497",
"http://blog.csdn.net/catoop/article/details/38849497",
"http://blog.csdn.net/catoop/article/details/38849497",
"http://blog.csdn.net/catoop/article/details/38849497",
"http://blog.csdn.net/catoop/article/details/38849497",
"http://blog.csdn.net/catoop/article/details/38849497",
"http://blog.csdn.net/catoop/article/details/38849497",
"http://blog.csdn.net/catoop/article/details/38849497",
"http://blog.csdn.net/catoop/article/details/38849497",
"http://blog.csdn.net/catoop/article/details/38849497",
"http://blog.csdn.net/catoop/article/details/38849497",
"http://blog.csdn.net/catoop/article/details/38849497",
"http://blog.csdn.net/catoop/article/details/38849497",
"http://blog.csdn.net/catoop/article/details/38849497",
"http://blog.csdn.net/catoop/article/details/38849497",
"http://blog.csdn.net/catoop/article/details/38849497",
"http://blog.csdn.net/catoop/article/details/38849497",
"http://blog.csdn.net/catoop/article/details/38849497",
"http://blog.csdn.net/catoop/article/details/38849497",
"http://blog.csdn.net/catoop/article/details/38849497" };
long start = System.currentTimeMillis();
try {
int pagecount = urisToGet.length;
ExecutorService executors = Executors.newFixedThreadPool(pagecount);
CountDownLatch countDownLatch = new CountDownLatch(pagecount);
for (int i = 0; i < pagecount; i++) {
HttpGet httpget = new HttpGet(urisToGet[i]);
config(httpget);
// 启动线程抓取
executors
.execute(new GetRunnable(urisToGet[i], countDownLatch));
}
countDownLatch.await();
executors.shutdown();
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
System.out.println("线程" + Thread.currentThread().getName() + ","
+ System.currentTimeMillis() + ", 所有线程已完成，开始进入下一步！");
}
long end = System.currentTimeMillis();
System.out.println("consume -> " + (end - start));
}
static class GetRunnable implements Runnable {
private CountDownLatch countDownLatch;
private String url;
public GetRunnable(String url, CountDownLatch countDownLatch) {
this.url = url;
this.countDownLatch = countDownLatch;
}
@Override
public void run() {
try {
System.out.println(HttpClientUtil.get(url));
} finally {
countDownLatch.countDown();
}
}
}
}
Post使用方法
// 其中 params 为 Map params
String ret = HttpClientUtil.post(url, params);
jsonRet = new JSONObject(ret);