尝试用HttpClient登陆淘宝的问题，求助各位大虾

今天调试了一天了，怎么都登陆不上，下面是我的代码，各位大虾看看。
import java.io.IOException;   
  
import org.apache.commons.httpclient.Cookie;   
import org.apache.commons.httpclient.Header;   
import org.apache.commons.httpclient.HttpClient;   
import org.apache.commons.httpclient.HttpException;   
import org.apache.commons.httpclient.NameValuePair;   
import org.apache.commons.httpclient.cookie.CookiePolicy;
import org.apache.commons.httpclient.cookie.CookieSpec;
import org.apache.commons.httpclient.methods.GetMethod;   
import org.apache.commons.httpclient.methods.PostMethod;   
  
  
public class Log { 

        private static final String LOGON_SITE = "http://www.taobao.com";
       private static final int PORT = 80;
        private static final String loginurl = "http://login.taobao.com/member/login.jhtml";   
        private static final String tokenurl = "http://login.taobao.com/member/login.jhtml?f=top&redirectURL=http%3A%2F%2Fwww.taobao.com%2F";
        
        public static void main(String args[]) throws HttpException, IOException { 
        
         //创建连接
         HttpClient client = new HttpClient();
         client.getHostConfiguration().setHost(LOGON_SITE, PORT);
         Cookie[] cookies = client.getState().getCookies(); 
         //获取_tb_token
         GetMethod get = new GetMethod(tokenurl);
         if(cookies!=null)
get.setRequestHeader("Cookie" , cookies.toString());
        
        client.executeMethod(get);         
        cookies = client.getState().getCookies();   //获取返回的cookie信息
    client.getState().addCookies(cookies); 
            System.out.println(cookies.toString());
            
    String response=get.getResponseBodyAsString().toString();
            //System.out.println(response);
        response.substring(response.indexOf("_tb_token_")+"_tb_token_".length());
        response = response.substring(response.indexOf("_tb_token_")+"_tb_token_".length());
        String value=response.substring(response.indexOf("value=")+"value='".length(),response.indexOf(">")-1);
get.releaseConnection();
          
 System.out.println("tbtoken = "+value);

        
        
         //登陆..
            String user="xxxxxxx";                         
            PostMethod post = new PostMethod(loginurl);   
            
            NameValuePair[] params= new NameValuePair[] {  
            new NameValuePair("_tb_token",value),
            new NameValuePair("action", "Authenticator"),
            new NameValuePair("callback",""),
            new NameValuePair("css_style",""),
            new NameValuePair("CtrlVersion","1,0,0,7"),
            new NameValuePair("event_submit_do_login", "anything"),      
            new NameValuePair("fc","2"),
            new NameValuePair("from","tb"),
            new NameValuePair("from_encoding",""),
            new NameValuePair("guf",""),
            new NameValuePair("gvfdcname","10"),
            new NameValuePair("isIgnore",""),
            new NameValuePair("llnick",""),
            new NameValuePair("loginType", "4"),
            new NameValuePair("longLogin","-1"),
            new NameValuePair("minipara",""),
            new NameValuePair("minititle",""),
            new NameValuePair("need_sign",""),
            new NameValuePair("need_user_id",""),
            new NameValuePair("not_duplite_str",""),
            new NameValuePair("popid",""),
            new NameValuePair("poy",""),
            new NameValuePair("pstrong","2"),
            new NameValuePair("sign",""),
            new NameValuePair("style","default"),
            new NameValuePair("support","000001"),
            new NameValuePair("tid","XOR_1_000000000000000000000000000000_63584425437F79740F06767C"),
            new NameValuePair("TPL_password", "3DES_2_000000000000000000000000000000_FE39B07DFF60A631"),
            new NameValuePair("TPL_redirect_url", "http://www.taobao.com/"),
            new NameValuePair("TPL_username", user), 
            }; 
            post.setRequestBody(params);
   post.setRequestHeader("Cookie" , cookies.toString());
            client.executeMethod(post);
            cookies = client.getState().getCookies();   //获取返回的cookie信息
   client.getState().addCookies(cookies);     //打印服务器返回信息
            String postresponse = post.getResponseBodyAsString().toString();
            System.out.println("post="+postresponse);
            post.releaseConnection(); 
            }
}
从服务器返回的信息是空，也就是postresponse是空。搞了一天了头都大了，是我登陆表单填写错了吗，还是什么问题啊..
另外还有就是提交登陆表单的时候，那个tid是哪里来的呢？ 虽然我是利用httpwatch抓取到，但是始终不明白是什么作用。
谢谢大虾们的帮忙啊~