import java.io.InputStream;
import java.io.InputStreamReader;
iimport java.io.UnsupportedEncodingException;

import java.util.*;

import org.apache.commons.httpclient.Header;
import org.apache.commons.httpclient.HostConfiguration;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpConnection;
import org.apache.commons.httpclient.MultiThreadedHttpConnectionManager;
import org.apache.commons.httpclient.NameValuePair;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.methods.PostMethod;

/**
* @author steven
*/
public class HttpClientExample {

//獲得ConnectionManager，設(shè)置相關(guān)參數(shù)
private static MultiThreadedHttpConnectionManager manager =
new MultiThreadedHttpConnectionManager();
private static int connectionTimeOut = 20000;
private static int socketTimeOut = 10000;
private static int maxConnectionPerHost = 5;
private static int maxTotalConnections = 40;

//標(biāo)志初始化是否完成的flag
private static boolean initialed = false;

//初始化ConnectionManger的方法
public static void SetPara() {
manager.getParams().setConnectionTimeout(connectionTimeOut);
manager.getParams().setSoTimeout(socketTimeOut);
manager.getParams()
.setDefaultMaxConnectionsPerHost(maxConnectionPerHost);
manager.getParams().setMaxTotalConnections(maxTotalConnections);
initialed = true;

}

//通過(guò)get方法獲取網(wǎng)頁(yè)內(nèi)容
public static String getGetResponseWithHttpClient(String url, String encode) {

HttpClient client = new HttpClient(manager);

if (initialed) {

HttpClientExample.SetPara();
}

GetMethod get = new GetMethod(url);
get.setFollowRedirects(true);

String result = null;
StringBuffer resultBuffer = new StringBuffer();

try {

client.executeMethod(get);

//在目標(biāo)頁(yè)面情況未知的條件下，不推薦使用getResponseBodyAsString()方法
//String strGetResponseBody = post.getResponseBodyAsString();
BufferedReader in = new BufferedReader(
new InputStreamReader(
get.getResponseBodyAsStream(),
get.getResponseCharSet()));

String inputLine = null;

while ((inputLine = in.readLine()) != null) {
resultBuffer.append(inputLine);

resultBuffer.append("\n");
}

in.close();

result = resultBuffer.toString();

//iso-8859-1 is the default reading encode
result = HttpClientExample.ConverterStringCode(resultBuffer.toString(),
get.getResponseCharSet(),
encode);
} catch (Exception e) {
e.printStackTrace();

result = "";

} finally {
get.releaseConnection();

return result;
}
}

public static String getPostResponseWithHttpClient(String url,
String encode) {
HttpClient client = new HttpClient(manager);

if (initialed) {
HttpClientExample.SetPara();
}

PostMethod post = new PostMethod(url);
post.setFollowRedirects(false);

StringBuffer resultBuffer = new StringBuffer();

String result = null;

try {
client.executeMethod(post);

BufferedReader in = new BufferedReader(

new InputStreamReader(
post.getResponseBodyAsStream(),
post.getResponseCharSet()));
String inputLine = null;

while ((inputLine = in.readLine()) != null) {
resultBuffer.append(inputLine);

resultBuffer.append("\n");
}

in.close();

//iso-8859-1 is the default reading encode
result = HttpClientExample.ConverterStringCode(resultBuffer.toString(),
post.getResponseCharSet(),
encode);
} catch (Exception e) {
e.printStackTrace();

result = "";

} finally {
post.releaseConnection();

return result;
}
}

public static String getPostResponseWithHttpClient(String url,
String encode,
NameValuePair[] nameValuePair) {
HttpClient client = new HttpClient(manager);

if (initialed) {
HttpClientExample.SetPara();
}

PostMethod post = new PostMethod(url);
post.setRequestBody(nameValuePair);
post.setFollowRedirects(false);

String result = null;
StringBuffer resultBuffer = new StringBuffer();

try {
client.executeMethod(post);
BufferedReader in = new BufferedReader(
new InputStreamReader(
post.getResponseBodyAsStream(),
post.getResponseCharSet()));
String inputLine = null;

while ((inputLine = in.readLine()) != null) {

resultBuffer.append(inputLine);
resultBuffer.append("\n");
}

in.close();

//iso-8859-1 is the default reading encode
result = HttpClientExample.ConverterStringCode(resultBuffer.toString(),
post.getResponseCharSet(),
encode);
} catch (Exception e) {
e.printStackTrace();

result = "";
} finally {
post.releaseConnection();

return result;
}
}

private static String ConverterStringCode(String source, String srcEncode, String destEncode) {
if (src != null) {
try {
return new String(src.getBytes(srcEncode), destEncode);
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return "";
}
} else {
return "";

}
}
}

--------------------------------------------------------------------------------
之后，就可以通過(guò)下面的代碼獲得目標(biāo)網(wǎng)頁(yè)：
String source = HttpClientExample.getGetResponseWithHttpClient("www.sina.com.cn", "GBK");

注意，在默認(rèn)情況下，HttpClient的Request的Head中
User-Agent的值是Jakarta Commons-HttpClient 3.0RC1，如果需要改變它（例如，變?yōu)镸ozilla/4.0），必須在調(diào)用之前運(yùn)行如下語(yǔ)句：
System.getProperties().setProperty("httpclient.useragent", "Mozilla/4.0");