httpClient Post传参方法

最近再使用httpclient，然后很纠结，有一点小理解，但又有迷惑，希望大家看一下，帮我解一下疑惑。

我是使用PostMethod 传参的，例子如下：

package com.isca.smp.control.daq.baseline.nsfocus;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import org.apache.commons.httpclient.Cookie;
import org.apache.commons.httpclient.Header;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpStatus;
import org.apache.commons.httpclient.NameValuePair;
import org.apache.commons.httpclient.methods.PostMethod;

import com.isca.framework.utils.security.SpringSecurityUtils;

public class Post {
public static void main(String[] args) throws Exception {
HttpClient httpClient = new HttpClient();// 创建 HttpClient 的实例
String url = "http://localhost:8080/smp/notice/notice.action";

PostMethod postMethod = new PostMethod(url);
// 填入各个表单域的值 　　
NameValuePair[] data = { new NameValuePair("username", "admin"),
new NameValuePair("password", "12334") };
// 将表单的值放入postMethod中 　　
postMethod.setRequestBody(data);
// 执行postMethod
int statusCode = httpClient.executeMethod(postMethod);
System.out.println(SpringSecurityUtils.getCurrentUserName());
//输出回应
// String a = postMethod.getResponseBodyAsString();
// System.out.println(a);
InputStream is = postMethod.getResponseBodyAsStream();
BufferedReader br = new BufferedReader(new InputStreamReader(is,
"utf-8"));
String line = "";
while ((line = br.readLine()) != null) {
System.out.println(line);
}

// 查看缓存
Cookie[] cookies = httpClient.getState().getCookies();
System.out.println("cookies length = " + cookies.length + " state="
+ statusCode);
if(cookies.length==0) return ;
for (int i = 0; i < cookies.length; i++) {
System.out.println("cookie - " + i + ":");
System.out.println(cookies.toString());
System.out.println(cookies[i].getDomain());
System.out.println(cookies[i].getName());
System.out.println(cookies[i].getPath());
System.out.println(cookies[i].getValue());
System.out.println("---------------------");
}
int a = HttpStatus.SC_OK;

// 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) {
Header header = postMethod.getResponseHeader("location");
String location = null;
if (header != null) {
location = header.getValue();
System.out.println("aaaaaaaa" + location);
} else {
System.out.println("bbbbbbbbbbbbb");
}
}
}
}

但是我想改成httppost传参就不行，代码如下，

public static void main(String[] args) throws Exception {
HttpClient httpclient = new DefaultHttpClient();
HttpClientParams.setCookiePolicy(httpclient.getParams(),CookiePolicy.BROWSER_COMPATIBILITY);

HttpPost httpost = new HttpPost("http://localhost:8080/smp/notice/notice.action");
HttpParams params=httpclient.getParams();
params.setParameter("username", "admin");
params.setParameter("password", "1q3445");
httpost.setParams(params);
//输出传的参数
System.out.println(params.getParameter("j_username"));
HttpResponse response = httpclient.execute(httpost);
HttpEntity entity = response.getEntity();
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);
}
}
}

我再noticeaction里面

String passwd = Struts2Utils.getRequest().getParameter("password");

接受不到参数，这是为什么那，两种方式有什么区别？纠结ing~~~~~~