jsessionid filter

最近因某專案需要做網站偽裝
突然注意到雖然網頁檔名變了但是卻有意無意的在URL中出現jessionid(等於還是昭告天下了)
所以就想找可以將jessionid過濾掉的方法..參考網址如下
http://www.blogjava.net/steady/archive/2007/09/08/143664.html

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;
import javax.servlet.http.HttpSession;
import java.io.IOException;

/**
 * Servlet filter which disables URL-encoded session identifiers.
 * 

 * 

 * Copyright (c) 2006, Craig Condit. All rights reserved.
 * 

 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 

 *   * Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright notice,
 *     this list of conditions and the following disclaimer in the documentation
 *     and/or other materials provided with the distribution.
 * 

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * 
 */
@SuppressWarnings("deprecation")
public class DisableUrlSessionFilter implements Filter {

    /**
     * Filters requests to disable URL-based session identifiers.
     */
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        // skip non-http requests
        if (!(request instanceof HttpServletRequest)) {
            chain.doFilter(request, response);
            return;
        }

        HttpServletRequest httpRequest = (HttpServletRequest) request;
        HttpServletResponse httpResponse = (HttpServletResponse) response;

        // clear session if session id in URL
        if (httpRequest.isRequestedSessionIdFromURL()) {
            HttpSession session = httpRequest.getSession();
            if (session != null) session.invalidate();
        }

        // wrap response to remove URL encoding
        HttpServletResponseWrapper wrappedResponse = new HttpServletResponseWrapper(httpResponse) {
            @Override
            public String encodeRedirectUrl(String url) {
                return url;
            }

            @Override
            public String encodeRedirectURL(String url) {
                return url;
            }

            @Override
            public String encodeUrl(String url) {
                return url;
            }

            @Override
            public String encodeURL(String url) {
                return url;
            }
        };

        // process next request in chain
        chain.doFilter(request, wrappedResponse);
    }

    /**
     * Unused.
     */
    public void init(FilterConfig config) throws ServletException {
    }

    /**
     * Unused.
     */
    public void destroy() {
    }