就是在前臺中呼叫proxy程式的servlet，設定引數servletName和其它引數。代理程式會將該請求傳送到目的地址的名稱為servletName的servlet中去，並將其它引數作為請求的引數，在得到結果後，將內容原樣輸出到請求頁面。

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import
 
 java.net.URL;
import java.net.URLEncoder;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class
 
 ProxyServlet extends HttpServlet {
    private String url;
    /**
     * 對servlet進行請求處理，並將結果在指定輸出流中輸出
     * 
     * @param os
     * @param servletName
     * @param parm
     * @throws IOException
     * @throws MalformedURLException
     */
    private void process(HttpServletRequest req, HttpServletResponse resp,
            String[] target) throws
 
 MalformedURLException, IOException {
        // 取得連線
        HttpURLConnection huc = (HttpURLConnection) new URL(url + target[0])
                .openConnection();
        // 設定連線屬性
        huc.setDoOutput(true);
        huc.setRequestMethod("POST");
        huc.setUseCaches(false);
        huc.setInstanceFollowRedirects(true);
        huc.setRequestProperty("Content-Type",
                "application/x-www-form-urlencoded");
        huc.connect();
        // 往目標servlet中提供引數
        OutputStream targetOS = huc.getOutputStream();
        targetOS.write(target[1].getBytes());
        targetOS.flush();
        targetOS.close();
        // 取得頁面輸出,並設定頁面編碼及快取設定
        resp.setContentType(huc.getContentType());
        resp.setHeader("Cache-Control", huc.getHeaderField("Cache-Control"));
        resp.setHeader("Pragma", huc.getHeaderField("Pragma"));
        resp.setHeader("Expires", huc.getHeaderField("Expires"));
        OutputStream os = resp.getOutputStream();
        // 將目標servlet的輸入流直接往頁面輸出
        InputStream targetIS = huc.getInputStream();
        int r;
        while ((r = targetIS.read()) != -1) {
            os.write(r);
        }
        targetIS.close();
        os.flush();
        os.close();
        huc.disconnect();
    }
    /**
     * 將引數中的目標分離成由目標servlet名稱和引數組成的陣列
     * 
     * @param queryString
     * @return
     * @throws UnsupportedEncodingException
     */
    private String[] parse(Map map) throws UnsupportedEncodingException {
        String[] arr = { "", "" };
        Iterator iter = map.entrySet().iterator();
        while (iter.hasNext()) {
            Map.Entry me = (Entry) iter.next();
            String[] varr = (String[]) me.getValue();
            if ("servletName".equals(me.getKey())) {
                // 取出servlet名稱
                arr[0] = varr[0];
            } else {
                // 重新組裝引數字串
                for (int i = 0; i < varr.length; i++) {
                    // 引數需要進行轉碼，實現字符集的統一
                    arr[1] += "&" + me.getKey() + "="
                            + URLEncoder.encode(varr[i], "utf-8");
                }
            }
        }
        arr[1] = arr[1].replaceAll("^&", "");
        return arr;
    }
    @Override
    public void init() throws ServletException {
        // 設定目標伺服器地址
        url = this.getInitParameter("url");
        if (!url.endsWith("/"))
            url = url + "/";
    }
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        this.doPost(req, resp);
    }
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        String[] target = parse(req.getParameterMap());
        process(req, resp, target);
    }
}