httpclient 登陆问题

有谁用过httpclient吗，我现在写了个登陆校内的例子，报302错误，不知道哪错了，请大家指点下，谢谢~代码如下:
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.cookie.Cookie;
import org.apache.http.entity.HttpEntityWrapper;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.protocol.HTTP;public class LoginMain { private static final String LOGIN_URL = "http://www.renren.com/"; public static void main(String[] args) {
DefaultHttpClient client = new DefaultHttpClient();
HttpGet httpget = new HttpGet(LOGIN_URL);
HttpResponse response = null;
HttpEntity entity = null;
try {
HttpPost post = new HttpPost("http://www.renren.com/PLogin.do");
List<NameValuePair> nvps = new ArrayList<NameValuePair>();
nvps.add(new BasicNameValuePair("User-Agent","Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN; rv:1.9.1.8) Gecko/20100202 Firefox/3.5.8"));
nvps.add(new BasicNameValuePair("email","用户名"));
nvps.add(new BasicNameValuePair("password","密码"));
nvps.add(new BasicNameValuePair("origURL","http://www.renren.com/Home.do"));
nvps.add(new BasicNameValuePair("domain","renren.com"));
// nvps.add(new BasicNameValuePair("loginForm","/PLogin.do"));
post.setEntity(new UrlEncodedFormEntity(nvps,HTTP.UTF_8));
response = client.execute(post);
entity = response.getEntity();
System.out.println("status =" + response.getStatusLine());
System.out.println("--------------");
if(entity!=null){
InputStream is = entity.getContent();
BufferedReader br = new BufferedReader(new InputStreamReader(is,"utf-8"));
String line = "";
while((line=br.readLine())!=null){
System.out.println(line);
}
}
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}