java网络爬虫连接超时解决[实战程序]

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;
    }
}

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