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預先安裝函式庫：Apache Commons HttpClient 3.x, Apache Commons Codec, Apache Commons Logging
程式碼：
httpclient.jsp:

<%@ page contentType="text/html;charset=big5" %>

<%@ page import="org.apache.commons.httpclient.*" %>

<%@ page import="org.apache.commons.httpclient.methods.*" %>

<%@ page import="org.apache.commons.httpclient.params.HttpMethodParams" %>

<%@ page import="java.io.*" %>

<%    

    String url = "http://tw.stock.yahoo.com/";

    

    String stockId = request.getParameter("stock_id");

    if (stockId != null) { 

      url += "q/q?s="+stockId;

    }

    

    // Create an instance of HttpClient.

    HttpClient client = new HttpClient();



    // Create a method instance.

    HttpMethod method = new GetMethod(url);

    

    // Provide custom retry handler is necessary

    method.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, 

    		new DefaultHttpMethodRetryHandler(3, false));



    try {

      // Execute the method.

      int statusCode = client.executeMethod(method);



      if (statusCode != HttpStatus.SC_OK) {

        System.err.println("Method failed: " + method.getStatusLine());

      }



      // Read the response body.

      byte[] responseBody = method.getResponseBody();



      // Deal with the response.

      // Use caution: ensure correct character encoding and is not binary data

      //System.out.println(new String(responseBody));

      

      String result = new String(responseBody, "Big5");

      if (stockId != null) {        

        result = result.substring(result.indexOf("nowrap><b>")+"nowrap><b>".length());

        result = result.substring(0, result.indexOf("</b>"));

        out.println(stockId + " Price Now: " + result);

      } else {

        out.println(result);

      }

    } catch (HttpException e) {

      System.err.println("Fatal protocol violation: " + e.getMessage());

      e.printStackTrace();

    } catch (IOException e) {

      System.err.println("Fatal transport error: " + e.getMessage());

      e.printStackTrace();

    } finally {

      // Release the connection.

      method.releaseConnection();

    } 

%>

參考資料：
http://hc.apache.org/httpclient-3.x/tutorial.html

改用Apache HttpComponents HttpClient 4撰寫的版本：
httpclient4.jsp:

<%@ page contentType="text/html;charset=big5" %>

<%@ page import="java.io.IOException" %>

<%@ page import="org.apache.http.client.ClientProtocolException" %>

<%@ page import="org.apache.http.client.HttpClient" %>

<%@ page import="org.apache.http.client.ResponseHandler" %>

<%@ page import="org.apache.http.client.methods.HttpGet" %>

<%@ page import="org.apache.http.impl.client.BasicResponseHandler" %>

<%@ page import="org.apache.http.impl.client.DefaultHttpClient" %>

<%    

    String url = "http://tw.stock.yahoo.com/";

    

    String stockId = request.getParameter("stock_id");

    if (stockId != null) { 

      url += "q/q?s="+stockId;

    }

    

   // Create an instance of HttpClient.

    HttpClient httpclient = new DefaultHttpClient();

    try {

    	// Create an HttpGet method instance.

    	HttpGet httpget = new HttpGet(url);



        System.out.println("executing request " + httpget.getURI());



        // Create a response handler

        ResponseHandler<String> responseHandler = new BasicResponseHandler();

        String responseBody = httpclient.execute(httpget, responseHandler);

        if (stockId != null) {

        	responseBody = responseBody.substring(responseBody.indexOf("nowrap><b>")+"nowrap><b>".length());

        	responseBody = responseBody.substring(0, responseBody.indexOf("</b>"));					

    		out.println(stockId + " Price Now: " + responseBody);

        } else {

        	out.println(responseBody);

        }

    } catch (ClientProtocolException e) {

		e.printStackTrace();

	} catch (IOException e) {

		e.printStackTrace();

	} finally {

        // When HttpClient instance is no longer needed,

        // shut down the connection manager to ensure

        // immediate deallocation of all system resources

        httpclient.getConnectionManager().shutdown();

    }   

%>

如果是在公司內部環境使用HttpClient 4去連外部網站須走proxy才能通時，
將原來這行:

HttpClient httpclient = new DefaultHttpClient();

修改為(假設proxy是http://10.160.3.88:8080/):

HttpHost proxy = new HttpHost("10.160.3.88", 8080);

HttpClient httpclient = new DefaultHttpClient();

httpclient.getParams().setParameter(ConnRoutePNames.DEFAULT_PROXY, proxy);

同時補上宣告:

<% @page import="org.apache.http.HttpHost" %>

<% @page import="org.apache.http.conn.params.ConnRoutePNames" %>

即可。