java httpclient问题
我写了一个demo，功能是多线程httpclient并发访问某个网站，最后返回的结果有好多500，还有好多refuse，我不知道这个500或者refuse是我的程序问题，还是我访问的那个网站的问题？
代码如下：

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

import java.util.concurrent.Semaphore;

import java.util.concurrent.TimeUnit;

import org.apache.http.HttpHost;

import org.apache.http.HttpResponse;

import org.apache.http.HttpVersion;

import org.apache.http.client.CookieStore;

import org.apache.http.client.methods.HttpPost;

import org.apache.http.client.protocol.ClientContext;

import org.apache.http.conn.routing.HttpRoute;

import org.apache.http.conn.scheme.PlainSocketFactory;

import org.apache.http.conn.scheme.Scheme;

import org.apache.http.conn.scheme.SchemeRegistry;

import org.apache.http.conn.ssl.SSLSocketFactory;

import org.apache.http.entity.ContentType;

import org.apache.http.entity.StringEntity;

import org.apache.http.impl.client.BasicCookieStore;

import org.apache.http.impl.client.DefaultHttpClient;

import org.apache.http.impl.conn.PoolingClientConnectionManager;

import org.apache.http.params.BasicHttpParams;

import org.apache.http.params.HttpConnectionParams;

import org.apache.http.params.HttpParams;

import org.apache.http.params.HttpProtocolParams;

import org.apache.http.protocol.BasicHttpContext;

import org.apache.http.protocol.HttpContext;

import org.apache.http.util.EntityUtils;



public class httpclient {



    public static String url = "";

    public static CookieStore cookieStore;

    public static DefaultHttpClient httpClient = null;



    public static DefaultHttpClient getHttpClient() {

        HttpParams params = new BasicHttpParams();

        HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1);

        HttpProtocolParams.setUserAgent(params, "HttpComponents/1.1");

        HttpProtocolParams.setUseExpectContinue(params, true);



        //设置连接超时时间 

        int REQUEST_TIMEOUT = 30 * 1000;	//设置请求超时10秒钟 

        int SO_TIMEOUT = 60 * 1000; 		//设置等待数据超时时间10秒钟 

        HttpConnectionParams.setConnectionTimeout(params, REQUEST_TIMEOUT);

        HttpConnectionParams.setSoTimeout(params, SO_TIMEOUT);

//        params.setParameter(CoreConnectionPNames.CONNECTION_TIMEOUT, REQUEST_TIMEOUT);

//        params.setParameter(CoreConnectionPNames.SO_TIMEOUT, SO_TIMEOUT);



        //设置访问协议 

        SchemeRegistry schreg = new SchemeRegistry();

        schreg.register(new Scheme("http", 80, PlainSocketFactory.getSocketFactory()));

        schreg.register(new Scheme("https", 443, SSLSocketFactory.getSocketFactory()));