HttpClient是一个非常好用的java开源项目，其作用是对用java程序对网站发起Http请求。

下面是鲁炬对HttpClient进行的简单封装，主要优点是，静态调用，自动识别网页字符集，伪装火狐/IE浏览器。

为什么不使用单例。以前是用单例模式，只创建一个HttpClient示例，后来发现用单例在并发情况下会出现bug，所以改为了每次调用都新建一个。

import java.io.IOException;

import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpException;
import org.apache.commons.httpclient.HttpMethod;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.lang.StringUtils;


/**
 * @author 鲁炬
 *
 */
public class HttpClientUtil {

  public static HttpClient getClient() {
    HttpClient client = new HttpClient();
    return client;
  }

  public static String getHtml(String url) throws HttpException, IOException {
    return getHtml(url, 80, null, null, 0, null);
  }

  public static String getHtml(String url, String cookie) throws HttpException, IOException {
    return getHtml(url, 80, null, null, 0, cookie);
  }

  public static String getHtml(String url, int port, String cookie) throws HttpException, IOException {
    return getHtml(url, port, null, null, 0, cookie);
  }

  public static String getHtml(String url, int port, String encoding, String proxyHost, int proxyPort, String cookie)
      throws HttpException, IOException {
    HttpClient httpClient = getClient();
    String rest = null;
    if(proxyHost != null && proxyPort != 0) httpClient.getHostConfiguration().setProxy(proxyHost, proxyPort);
    HttpMethod method = new GetMethod(url);
    if(!StringUtils.isBlank(cookie)) {
      method.addRequestHeader("Cookie", cookie);
    }
    method.addRequestHeader("User-Agent", "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; .NET CLR 2.0.50727");
    //Mozilla/5.0 (Windows NT 6.1; rv:7.0.1) Gecko/20100101 Firefox/7.0.1
    httpClient.executeMethod(method);

    //根据http头解析正确的字符集
    String header = method.getResponseHeader("Content-Type").getValue();
    if(header.contains("charset=")) {
      encoding = header.substring(header.indexOf("charset=") + "charset=".length(), header.length());
    }
    if(encoding == null) encoding = "GBK";

    rest = new String(method.getResponseBody(), encoding);
    method.releaseConnection();
    return rest;
  }

  public static void main(String[] args) throws HttpException, IOException {
    String url = "http://www.ccb.com";
    System.out.println(getHtml(url));
  }
}