向精通commons-httpclient的兄弟请教个问题

Question

我要利用commons-httplcient 4.3 抓紧 :https://investorservice.cfmmc.com/veriCode.do ,这是个图片.我的抓取程序是：
import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;
import java.security.KeyStore;import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.conn.scheme.Scheme;
import org.apache.http.conn.ssl.SSLSocketFactory;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;public class TestOCR { /**
 * @param args
 */
public static void main(String[] args) throws Exception {

  DefaultHttpClient httpclient = new DefaultHttpClient();
        try {
            KeyStore trustStore  = KeyStore.getInstance(KeyStore.getDefaultType());
            FileInputStream instream = new FileInputStream(new File("E:\\jdk1.6.0_18\\jre\\lib\\security\\my.truststore"));  //my.keystore
            try {
                trustStore.load(instream, "123456".toCharArray());
            } finally {
                try { instream.close(); } catch (Exception ignore) {}
            }
            SSLSocketFactory socketFactory = new SSLSocketFactory(trustStore);
            Scheme sch = new Scheme("https", 443, socketFactory);
            httpclient.getConnectionManager().getSchemeRegistry().register(sch);
           
            HttpGet httpget = new HttpGet("https://investorservice.cfmmc.com/veriCode.do");
            
            System.out.println("executing request " + httpget.getRequestLine());
            HttpResponse response = httpclient.execute(httpget);
            System.out.println(response.getEntity().getContentLength());
            
            HttpEntity entity = response.getEntity();
            System.out.println("----------------------------------------");
            System.out.println(response.getStatusLine());
            if (entity != null) {
                System.out.println("Response content length: " + entity.getContentLength());
                InputStream is=entity.getContent();
                System.out.println("is length: " + is.available());
            }
            
            EntityUtils.consume(entity);
            
        } finally {
            // When HttpClient instance is no longer needed,
            // shut down the connection manager to ensure
            // immediate deallocation of all system resources
            httpclient.getConnectionManager().shutdown();
        }


}}
出错原因：
 System.out.println(response.getEntity().getContentLength());输出的结果是-1
这是什么原因，有没有感兴趣的兄弟，试试看，https的ssl证书，你可以在：
http://download.csdn.net/detail/pdw2009/4075626
下载，然后导入jdk中。分不够可以再加，有兴趣的兄弟可以研究一下。