本文研究的主要是java网络爬虫连接超时的问题，具体如下。
在网络爬虫中，经常会遇到如下报错。即连接超时。针对此问题，一般解决思路为：将连接时间、请求时间设置长一下。如果出现连接超时的情况，则在重新请求【设置重新请求次数】。
Exception in thread "main" java.net.ConnectException: Connection timed out: connect
下面的代码便是使用httpclient解决连接超时的样例程序。直接上程序。
package daili;
import java.io.IOException;
import java.net.URI;
import org.apache.http.HttpRequest;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.params.CookiePolicy;
import org.apache.http.client.protocol.ClientContext;
import org.apache.http.impl.client.BasicCookieStore;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.impl.client.DefaultHttpRequestRetryHandler;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.impl.cookie.BasicClientCookie2;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.params.HttpParams;
import org.apache.http.protocol.BasicHttpContext;
import org.apache.http.protocol.ExecutionContext;
import org.apache.http.protocol.HttpContext;
import org.apache.http.util.EntityUtils;
/*
* author:合肥工业大学 管院学院 钱洋
*1563178220@qq.com
*/
public class Test1 {
public static void main(String[] args) throws ClientProtocolException, IOException, InterruptedException {
getRawHTML("http://club.autohome.com.cn/bbs/forum-c-2098-1.html#pvareaid=103447");
}
public static String getRawHTML ( String url ) throws ClientProtocolException, IOException, InterruptedException{
//初始化
DefaultHttpClient httpclient = new DefaultHttpClient();
httpclient.getParams().setParameter("http.protocol.cookie-policy",
CookiePolicy.BROWSER_COMPATIBILITY);
//设置参数
HttpParams params = httpclient.getParams();
//连接时间
HttpConnectionParams.setConnectionTimeout(params, 6000);
HttpConnectionParams.setSoTimeout(params, 6000*20);
//超时重新请求次数
DefaultHttpRequestRetryHandler dhr = new DefaultHttpRequestRetryHandler(5,true);
HttpContext localContext = new BasicHttpContext();
HttpRequest request2 = (HttpRequest) localContext.getAttribute(
ExecutionContext.HTTP_REQUEST);
httpclient.setHttpRequestRetryHandler(dhr);
BasicCookieStore cookieStore = new BasicCookieStore();
BasicClientCookie2 cookie = new BasicClientCookie2("Content-Type","text/html;charset=UTF-8");
BasicClientCookie2 cookie1 = new BasicClientCookie2("User-Agent","Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36");
cookieStore.addCookie(cookie);
cookieStore.addCookie(cookie1);
localContext.setAttribute(ClientContext.COOKIE_STORE, cookieStore);
HttpGet request = new HttpGet();
request.setURI(URI.create(url));
HttpResponse response = null;
String rawHTML = "";
response = httpclient.execute(request,localContext);
int StatusCode = response.getStatusLine().getStatusCode();
//获取响应状态码
System.out.println(StatusCode);
if(StatusCode == 200){
//状态码200表示响应成功
//获取实体内容
rawHTML = EntityUtils.toString (response.getEntity());
System.out.println(rawHTML);
//输出实体内容
EntityUtils.consume(response.getEntity());
//消耗实体
} else {
//关闭HttpEntity的流实体
EntityUtils.consume(response.getEntity());
//消耗实体
Thread.sleep(20*60*1000);
//如果报错先休息30分钟
}
httpclient.close();
System.out.println(rawHTML);
return rawHTML;
}
}
结果：
总结
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