Java做的简单爬虫的问题

这是我的程序的错误!不知道怎么回事
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URI;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;

import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpUriRequest;
import org.apache.http.client.methods.RequestBuilder;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;

import Icrawl.ICrawler;
import pojos.CrawlResultPojo;
import pojos.UrlPojo;

public class HttpClientCrawlerImpl implements ICrawler {
public CloseableHttpClient httpclient = HttpClients.custom().build();

@Override
public CrawlResultPojo crawl(UrlPojo urlPojo) {
    if (urlPojo == null) {
        return null;
    }
    CrawlResultPojo crawlResultPojo = new CrawlResultPojo();
    CloseableHttpResponse response1 = null;
    BufferedReader br = null;
    try {
        HttpGet httpget = new HttpGet(urlPojo.getUrl());
        response1 = httpclient.execute(httpget);
        HttpEntity entity = response1.getEntity();
        InputStreamReader isr = new InputStreamReader(entity.getContent(),
                "utf-8");
        br = new BufferedReader(isr);

        String line = null;
        StringBuilder stringBuilder = new StringBuilder();
        while ((line = br.readLine()) != null) {
            stringBuilder.append(line + "\n");
        }
        crawlResultPojo.setSuccess(true);
        crawlResultPojo.setPageContent(stringBuilder.toString());
        return crawlResultPojo;
    } catch (Exception e) {
        e.printStackTrace();
        crawlResultPojo.setSuccess(false);
    } finally {
        if (response1 != null) {
            try {
                response1.close();
            } catch (IOException e1) {
                e1.printStackTrace();
            }
        }
        if (br != null) {
            try {
                br.close();
            } catch (IOException e1) {
                e1.printStackTrace();
            }
        }
    }

    return crawlResultPojo;
}

/**
 * 传入加入参数post参数的url pojo
 */
public CrawlResultPojo crawl4Post(UrlPojo urlPojo) {
    if (urlPojo == null) {
        return null;
    }
    CrawlResultPojo crawlResultPojo = new CrawlResultPojo();
    CloseableHttpResponse response1 = null;
    BufferedReader br = null;
    try {
        RequestBuilder rb = RequestBuilder.post().setUri(
                new URI(urlPojo.getUrl()));

        // .addParameter("IDToken1",
        // "username").addParameter("IDToken2", "password").build();

        Map<String, Object> parasMap = urlPojo.getParasMap();
        if (parasMap != null) {
            for (Entry<String, Object> entry : parasMap.entrySet()) {
                rb
                        .addParameter(entry.getKey(), entry.getValue()
                                .toString());
            }
        }
        HttpUriRequest httpRequest = rb.build();
        response1 = httpclient.execute(httpRequest);
        HttpEntity entity = response1.getEntity();
        InputStreamReader isr = new InputStreamReader(entity.getContent(),
                "utf-8");
        br = new BufferedReader(isr);

        String line = null;
        StringBuilder stringBuilder = new StringBuilder();
        while ((line = br.readLine()) != null) {
            stringBuilder.append(line + "\n");
        }
        crawlResultPojo.setSuccess(true);
        crawlResultPojo.setPageContent(stringBuilder.toString());
        return crawlResultPojo;
    } catch (Exception e) {
        e.printStackTrace();
        crawlResultPojo.setSuccess(false);
    } finally {
        if (response1 != null) {
            try {
                response1.close();
            } catch (IOException e1) {
                e1.printStackTrace();
            }
        }
        if (br != null) {
            try {
                br.close();
            } catch (IOException e1) {
                e1.printStackTrace();
            }
        }
    }

    return crawlResultPojo;
}

@SuppressWarnings("unused")
public static void main(String[] args) throws Exception {
    HttpClientCrawlerImpl httpClientCrawlerImpl = new HttpClientCrawlerImpl();
    String url = "http://www.wdzj.com/front_select-platt";
    UrlPojo urlPojo = new UrlPojo(url);
    Map<String, Object> parasMap = new HashMap<String, Object>();

    int max_page_number = 1000;

    parasMap.put("currPage", 30);
    parasMap.put("params", "");
    parasMap.put("sort", 0);
    urlPojo.setParasMap(parasMap);

    CrawlResultPojo resultPojo = httpClientCrawlerImpl.crawl4Post(urlPojo);

    if (resultPojo != null) {
        System.out.println(resultPojo);
    }
}

}

这是代码，怎么解决这个报错啊？？？

Apache httpclient版本问题

http://www.jb51.net/article/42048.htm