httpclient 4.0 乱码问题 - 急

代码如下，web服务器的缺省字符集可能改变了，返回的总是乱码，前两天都还好的：
那位高手请帮忙分析一下原因，给出解决方案。

package com.zdy.stock;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.URISyntaxException;

import org.apache.http.HttpEntity;
import org.apache.http.HttpException;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpUriRequest;
import org.apache.http.client.utils.URIUtils;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.protocol.HTTP;

public class HttpClientTest {

public static void main(String[] args) {
HttpClient client = new DefaultHttpClient();
//client.getParams().setParameter("http.protocol.content-charset", "UTF-8");
client.getParams().setParameter(HTTP.CONTENT_ENCODING, "UTF-8");
//client.getParams().setParameter(HTTP.CHARSET_PARAM, "UTF-8");
//client.getParams().setParameter(HTTP.DEFAULT_PROTOCOL_CHARSET, "UTF-8");
HttpResponse response = null;
HttpUriRequest uriRequest = null;
//HttpGet httpGet = null;
String webPageContent = null;
try {
uriRequest = new HttpGet(URIUtils.createURI("http","bill.finance.sina.com.cn",80,"bill/detail.php","stock_code=sh601699",null));
//uriRequest.getParams().setParameter(HTTP.CONTENT_ENCODING, "UTF-8");
//uriRequest.getParams().setParameter(HTTP.DEFAULT_PROTOCOL_CHARSET, "UTF-8");
//uriRequest.getParams().setParameter(HTTP.DEFAULT_CONTENT_CHARSET, "UTF-8");
//uriRequest.getParams().setParameter(HTTP.CHARSET_PARAM, "UTF-8");
uriRequest.setHeader("Content-type", "text/xml; charset=GB2312");
uriRequest.setHeader("User-Agent","Mozilla/4.0 (compatible; MSIE 6.0; Windows 2000)");
} catch (URISyntaxException e1) {
e1.printStackTrace();
}

int tryCount = 0;
boolean success = false;
while (tryCount < 10 && !success) {
try {
tryCount++;
//response = client.execute(httpGet);
response = client.execute(uriRequest);
//response.setLocale(Locale.CHINA);
System.out.println("Locale = " + response.getLocale());
//client.getParams().setParameter(HTTP.CONTENT_ENCODING, "UTF-8");
//response.addHeader(HTTP.CONTENT_ENCODING, "UTF-8");
success = true;
} catch (HttpException e) {
if(tryCount==10) e.printStackTrace();
else System.out.print("HttpException,Try again!");
success = false;
} catch (IOException e) {
if(tryCount==10) e.printStackTrace();
else System.out.print("IOException,Try again!");
success = false;
}
}

HttpEntity entity = response.getEntity();

BufferedReader in = null;
if (entity != null) {
try {
in = new BufferedReader(new InputStreamReader(entity.getContent(),"GBK"));
//in = new BufferedReader(new InputStreamReader(entity.getContent()));

StringBuffer buffer = new StringBuffer();
String line = null;
while ((line = in.readLine()) != null) {
buffer.append(line);
buffer.append('\n');
}
webPageContent = buffer.toString();
} catch (IOException e) {
e.printStackTrace();
}
}

byte [] b=null;

try {
b = webPageContent.getBytes("UTF-8");
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
try {
String name = new String(b, "UTF-8");
System.out.print(name);
name = new String(b, "GB2312");
System.out.print(name);
name = new String(b, "GBK");
System.out.print(name);
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}

}