Java tutorial
/** * This file Copyright (c) 2010-2012 Magnolia International * Ltd. (http://www.magnolia-cms.com). All rights reserved. * * * This file is dual-licensed under both the Magnolia * Network Agreement and the GNU General Public License. * You may elect to use one or the other of these licenses. * * This file is distributed in the hope that it will be * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the * implied warranty of MERCHANTABILITY or FITNESS FOR A * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT. * Redistribution, except as permitted by whichever of the GPL * or MNA you select, is prohibited. * * 1. For the GPL license (GPL), you can redistribute and/or * modify this file under the terms of the GNU General * Public License, Version 3, as published by the Free Software * Foundation. You should have received a copy of the GNU * General Public License, Version 3 along with this program; * if not, write to the Free Software Foundation, Inc., 51 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * 2. For the Magnolia Network Agreement (MNA), this file * and the accompanying materials are made available under the * terms of the MNA which accompanies this distribution, and * is available at http://www.magnolia-cms.com/mna.html * * Any modifications to this file must keep this entire header * intact. * */ package info.magnolia.cms.util; import java.io.IOException; import java.net.MalformedURLException; import java.net.URL; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.lang.ClassUtils; import org.apache.commons.lang.StringUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * Provides support for a simple syntax form of doing redirects and forwards. You pass it a url prefixed with either * "redirect:", "permanent:" or "forward:". The context path is added to the url. * * @version $Id$ */ public class RequestDispatchUtil { private static final Logger log = LoggerFactory.getLogger(RequestDispatchUtil.class); public static final String REDIRECT_PREFIX = "redirect:"; public static final String PERMANENT_PREFIX = "permanent:"; public static final String FORWARD_PREFIX = "forward:"; /** * Returns true if processing took place, even if it fails. */ public static boolean dispatch(String targetUri, HttpServletRequest request, HttpServletResponse response) { if (targetUri == null) { return false; } if (targetUri.startsWith(REDIRECT_PREFIX)) { String redirectUrl = StringUtils.substringAfter(targetUri, REDIRECT_PREFIX); try { if (isInternal(redirectUrl)) { redirectUrl = request.getContextPath() + redirectUrl; } response.sendRedirect(response.encodeRedirectURL(redirectUrl)); } catch (IOException e) { log.error("Failed to redirect to {}:{}", targetUri, e.getMessage()); } return true; } if (targetUri.startsWith(PERMANENT_PREFIX)) { String permanentUrl = StringUtils.substringAfter(targetUri, PERMANENT_PREFIX); try { if (isInternal(permanentUrl)) { if (isUsingStandardPort(request)) { permanentUrl = new URL(request.getScheme(), request.getServerName(), request.getContextPath() + permanentUrl).toExternalForm(); } else { permanentUrl = new URL(request.getScheme(), request.getServerName(), request.getServerPort(), request.getContextPath() + permanentUrl).toExternalForm(); } } response.setStatus(HttpServletResponse.SC_MOVED_PERMANENTLY); response.setHeader("Location", permanentUrl); } catch (MalformedURLException e) { log.error("Failed to create permanent url to redirect to {}:{}", targetUri, e.getMessage()); } return true; } if (targetUri.startsWith(FORWARD_PREFIX)) { String forwardUrl = StringUtils.substringAfter(targetUri, FORWARD_PREFIX); try { request.getRequestDispatcher(forwardUrl).forward(request, response); } catch (Exception e) { log.error("Failed to forward to {} - {}:{}", new Object[] { forwardUrl, ClassUtils.getShortClassName(e.getClass()), e.getMessage() }); } return true; } return false; } private static boolean isUsingStandardPort(HttpServletRequest request) { String requestScheme = request.getScheme(); int serverPort = request.getServerPort(); return (serverPort == 80 && "http".equals(requestScheme)) || (serverPort == 443 && "https".equals(requestScheme)); } private static boolean isInternal(String url) { return !url.startsWith("http://") && !url.startsWith("https://"); } }