Apache HttpClient 连接池的使用

import java.io.IOException;
import java.util.Random;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.HttpVersion;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.conn.scheme.PlainSocketFactory;
import org.apache.http.conn.scheme.Scheme;
import org.apache.http.conn.scheme.SchemeRegistry;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.CoreConnectionPNames;
import org.apache.http.params.CoreProtocolPNames;
import org.apache.http.params.HttpParams;

public class HttpClientUtils {
 private static final Log log = LogFactory.getLog(HttpClientUtils.class);
 private static ThreadSafeClientConnManager cm = null;
 static {
  SchemeRegistry schemeRegistry = new SchemeRegistry();
  schemeRegistry.register(new Scheme("http",80,PlainSocketFactory
    .getSocketFactory()));

  cm = new ThreadSafeClientConnManager(schemeRegistry);
  try {
   int maxTotal = 100;
   cm.setMaxTotal(maxTotal);
  } catch (NumberFormatException e) {
   log.error(
     "Key[httpclient.max_total] Not Found in systemConfig.properties",e);
  }
  // 每条通道的并发连接数设置（连接池）
  try {
   int defaultMaxConnection = 50;
   cm.setDefaultMaxPerRoute(defaultMaxConnection);
  } catch (NumberFormatException e) {
   log.error(
     "Key[httpclient.default_max_connection] Not Found in systemConfig.properties",e);
  }
 }

 public static HttpClient getHttpClient() {
  HttpParams params = new BasicHttpParams();
  params.setParameter(CoreProtocolPNames.PROTOCOL_VERSION,HttpVersion.HTTP_1_1);
  params.setParameter(CoreConnectionPNames.CONNECTION_TIMEOUT,3000); // 3000ms
  return new DefaultHttpClient(cm,params);
 }

 public static void release() {
  if (cm != null) {
   cm.shutdown();
  }
 }

 public static void main(String[] args) throws ClientProtocolException,IOException {
  Random r = new Random();
  for (int i = 0; i < 10; i++) {
   long l1 = System.currentTimeMillis();
   HttpClient client = getHttpClient();

   HttpGet get = new HttpGet("http://www.baidu.com/s?wd="
     + r.nextInt(5000));
   HttpResponse response = client.execute(get);
   if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
    HttpEntity entity = response.getEntity();
    long l = entity.getContentLength();
    System.out.println("回应结果长度:" + l);
   }
   System.out.println("查询耗时" + (System.currentTimeMillis() - l1));
  }
 }

}