httpclient http连接池 demo

HttpClient4.x之前没有连接池的概念，多少次请求就会建立多少个IO，在访问量巨大的情况下服务器的IO可能会耗尽。最新HttpClient4.2有连接池的东西在里头，使用PoolingClientConnectionManager，具体可以参考官方文档，里面有详细介绍。

关于PoolingClientConnectionManager
介绍原文是这样的：

 

PoolingClientConnectionManager is a more complex implementation that manages a pool of client connections and is able to service connection requests from multiple execution threads. Connections are pooled on a per route basis.
A request for a route for which the manager already has a persistent connection available in the pool will be serviced by leasing a connection from the pool rather than creating a brand new connection.

PoolingClientConnectionManager maintains a maximum limit of connections on a per route basis and in total. Per default this implementation will create no more than 2 concurrent connections per given route and no more 20 connections
in total. For many real-world applications these limits may prove too constraining, especially if they use HTTP as a transport protocol for their services. Connection limits can be adjusted using the appropriate HTTP parameters.

 

示例：

HttpConnectionManager.java

 

public class HttpConnectionManager { 

	private static HttpParams httpParams;
	private static PoolingClientConnectionManager cm;

	/**
	 * 最大连接数
	 */
	public final static int MAX_TOTAL_CONNECTIONS = 200;
	/**
	 * 获取连接的最大等待时间
	 */
	public final static int WAIT_TIMEOUT = 60000;
	/**
	 * 每个路由最大连接数
	 */
	public final static int MAX_ROUTE_CONNECTIONS = 300;
	/**
	 * 连接超时时间
	 */
	public final static int CONNECT_TIMEOUT = 10000;
	/**
	 * 读取超时时间
	 */
	public final static int READ_TIMEOUT = 10000;

	static {
		SchemeRegistry schemeRegistry = new SchemeRegistry();
		schemeRegistry.register(
				new Scheme("http",80,PlainSocketFactory.getSocketFactory()));
		schemeRegistry.register(
				new Scheme("https", 443, SSLSocketFactory.getSocketFactory()));
		
		cm = new PoolingClientConnectionManager(schemeRegistry);
		cm.setMaxTotal(200);
		cm.setDefaultMaxPerRoute(80);
		
		HttpParams params = new BasicHttpParams();
		params.setParameter(CoreConnectionPNames.CONNECTION_TIMEOUT,CONNECT_TIMEOUT);
		params.setParameter(CoreConnectionPNames.SO_TIMEOUT, READ_TIMEOUT);
	}

	public static HttpClient getHttpClient() {
		return new DefaultHttpClient(cm, httpParams);
	}

}

DownloadTask.java

 

import java.io.IOException;
import java.io.InputStream;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.params.CoreConnectionPNames;

public class DownloadTask implements Runnable {

	private HttpClient httpClient = HttpConnectionPoolManager.getHttpClient();

	@Override
	public void run() {
		
		String url = "http://www.baidu.com";
		download(url);
	}

	public void download(String url) {

		
		HttpGet httpget = null;
		InputStream in = null;

		try {
			httpget = new HttpGet(url);

			httpget.setHeader("User-Agent","Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.79 Safari/537.1");
			httpget.setHeader("Accept","text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
			httpget.getParams().setParameter(CoreConnectionPNames.SO_TIMEOUT,1000 * 20);
			
			HttpResponse resp = httpClient.execute(httpget);

			int respCode = resp.getStatusLine().getStatusCode();

			if (respCode == HttpStatus.SC_OK) {

				HttpEntity entity = resp.getEntity();

				if (entity != null) {

					in = entity.getContent();

					sleep(1000);

					System.out.println("请求成功了..."
							+ Thread.currentThread().getName() + url);
				}

			} else {
				System.out.println("请求失败了..."
						+ Thread.currentThread().getName() + url);
				if(httpget!=null)
					httpget.abort();
			}

		} catch (ClientProtocolException e) {
			e.printStackTrace();
			if(httpget!=null)
				httpget.abort();

		} catch (IOException e) {
			e.printStackTrace();
			if(httpget!=null)
				httpget.abort();

		} catch (Exception e) { // 捕获最大的异常
			e.printStackTrace();
			if(httpget!=null)
				httpget.abort();
		} finally {
			if (in != null) {
				try {
					in.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
	}

	public void sleep(int time) throws InterruptedException {
		Thread.sleep(time);
	}
}

测试类

 

public class Test {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		
		for(int i=0;i<8;i++){
			new Thread(new DownloadTask()).start();
		}
		
	}

}

 

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