encodeurltag.java

老外的在线考试

/*
 * Core - Library of useful classes that are used in many CyberDemia projects.
 * Copyright (C) 2004 CyberDemia Research and Services
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA  02111-1307, USA.
 *
 * See the COPYING file located in the top-level-directory of
 * the archive of this library for complete text of license.
 */
package com.cyberdemia.jsp;

import javax.servlet.http.*;
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;
import java.io.IOException;
import org.apache.struts.Globals;

/**
 * EncodeUrlTag encodes a raw URL with Struts transaction token (if available, otherwise a random token is used)
 * and session ID (if required). It also prepends the context path.
 *
 * @author Alexander Yap
 * @version $Revision: 1.1 $ at $Date: 2004/03/22 06:56:38 $ by $Author: alexycyap $
 *
 */
public class EncodeUrlTag extends BodyTagSupport
{
	public int doAfterBody() throws JspException
	{
		BodyContent body = getBodyContent();
		String targetUrl = body.getString();
		String paramPrefix = (targetUrl.indexOf("?")!=-1) ? "&" : "?";
		body.clearBody();
		try
		{
			HttpServletResponse response = (HttpServletResponse)pageContext.getResponse();
			HttpServletRequest request = (HttpServletRequest)pageContext.getRequest();
			HttpSession session = pageContext.getSession();
			Object transactionToken = (session!=null) ? session.getAttribute(Globals.TRANSACTION_TOKEN_KEY) : null;
			boolean relativeRoot = Boolean.valueOf( m_relativeRoot ).booleanValue();
			StringBuffer urlBuf = new StringBuffer();

			if (!relativeRoot)
			{
				urlBuf.append(request.getContextPath());
			}
			urlBuf.append(targetUrl);

			if ( (transactionToken!=null) && (Boolean.valueOf( m_token ).booleanValue()))
			{
				urlBuf.append(paramPrefix);
				urlBuf.append(org.apache.struts.taglib.html.Constants.TOKEN_KEY);
				urlBuf.append("=");
				urlBuf.append(transactionToken  );
			}
			else
			{
				if (Boolean.valueOf( m_random ).booleanValue())
				{
					urlBuf.append(paramPrefix);
					urlBuf.append("xxx=");
					urlBuf.append(Math.random() );
				}
			}
			String encodedUrl = response.encodeURL( urlBuf.toString() );

			getPreviousOut().print( encodedUrl );
		}
		catch (IOException ioex)
		{
			throw new JspException("Error rewriting encoded Url "+targetUrl,ioex);
		}
		return SKIP_BODY;
	}

	public void setRelativeRoot(String root)
	{
		m_relativeRoot = root;
	}

	public void setRandom(String rnd)
	{
		m_random = rnd;
	}

	public void setToken(String token)
	{
		m_token = token;
	}

	private String m_relativeRoot = "false";
	private String m_random = "true";
	private String m_token = "true";
}