httpclient java 高手 高手帮忙啊 谢谢

package com.zhizun.test;import java.io.IOException;import org.apache.commons.httpclient.Header;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpException;
import org.apache.commons.httpclient.HttpStatus;
import org.apache.commons.httpclient.NameValuePair;
import org.apache.commons.httpclient.methods.PostMethod;public class TestPost {
public static void main(String args[]){
HttpClient httpClient = new HttpClient();
String url = "http://www.newsmth.net/bbslogin2.php";
PostMethod postMethod = new PostMethod(url);
// 填入各个表单域的值
NameValuePair[] data = { new NameValuePair("id", "tianyake"),
new NameValuePair("passwd", "830411") };
// 将表单的值放入postMethod中
postMethod.setRequestBody(data);
// 执行postMethod 
int statusCode;
try {

statusCode = httpClient.executeMethod(postMethod);
System.err.println(statusCode);
// HttpClient对于要求接受后继服务的请求，象POST和PUT等不能自动处理转发
// 301或者302
// if (statusCode == HttpStatus.SC_MOVED_PERMANENTLY || statusCode == HttpStatus.SC_MOVED_TEMPORARILY) 
//
// {   
// // 从头中取出转向的地址   
Header locationHeader = postMethod.getResponseHeader("location"); 
System.err.println(postMethod.getStatusCode());
System.err.println(locationHeader);
String location = null;  
if (locationHeader != null) {  
location = locationHeader.getValue();   

System.out.println("The page was redirected to:" + location);   
} else {     
System.err.println("Location field value is null.");    }          
// }
} catch (HttpException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
postMethod.releaseConnection();
}

}
}
结果为200
200
null
Location field value is null.