Remove ResourceServlet deprecated in 4.3.x
Issue: SPR-15984
This commit is contained in:
Rossen Stoyanchev
parent
9c216c2144
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132022861e
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@ -1,346 +0,0 @@
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/*
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* Copyright 2002-2017 the original author or authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.springframework.web.servlet;
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import java.io.IOException;
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import javax.servlet.RequestDispatcher;
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import javax.servlet.ServletException;
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import javax.servlet.http.HttpServletRequest;
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import javax.servlet.http.HttpServletResponse;
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import org.springframework.lang.Nullable;
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import org.springframework.util.AntPathMatcher;
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import org.springframework.util.Assert;
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import org.springframework.util.PathMatcher;
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import org.springframework.util.StringUtils;
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import org.springframework.web.context.support.ServletContextResource;
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/**
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* Simple servlet that can expose an internal resource, including a
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* default URL if the specified resource is not found. An alternative,
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* for example, to trying and catching exceptions when using JSP include.
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*
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* <p>A further usage of this servlet is the ability to apply last-modified
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* timestamps to quasi-static resources (typically JSPs). This can happen
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* as bridge to parameter-specified resources, or as proxy for a specific
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* target resource (or a list of specific target resources to combine).
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*
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* <p>A typical usage would map a URL like "/ResourceServlet" onto an instance
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* of this servlet, and use the "JSP include" action to include this URL,
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* with the "resource" parameter indicating the actual target path in the WAR.
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*
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* <p>The {@code defaultUrl} property can be set to the internal
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* resource path of a default URL, to be rendered when the target resource
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* is not found or not specified in the first place.
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*
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* <p>The "resource" parameter and the {@code defaultUrl} property can
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* also specify a list of target resources to combine. Those resources will be
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* included one by one to build the response. If last-modified determination
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* is active, the newest timestamp among those files will be used.
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*
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* <p>The {@code allowedResources} property can be set to a URL
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* pattern of resources that should be available via this servlet.
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* If not set, any target resource can be requested, including resources
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* in the WEB-INF directory!
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*
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* <p>If using this servlet for direct access rather than via includes,
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* the {@code contentType} property should be specified to apply a
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* proper content type. Note that a content type header in the target JSP will
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* be ignored when including the resource via a RequestDispatcher include.
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*
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* <p>To apply last-modified timestamps for the target resource, set the
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* {@code applyLastModified} property to true. This servlet will then
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* return the file timestamp of the target resource as last-modified value,
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* falling back to the startup time of this servlet if not retrievable.
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*
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* <p>Note that applying the last-modified timestamp in the above fashion
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* just makes sense if the target resource does not generate content that
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* depends on the HttpSession or cookies; it is just allowed to evaluate
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* request parameters.
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*
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* <p>A typical case for such last-modified usage is a JSP that just makes
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* minimal usage of basic means like includes or message resolution to
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* build quasi-static content. Regenerating such content on every request
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* is unnecessary; it can be cached as long as the file hasn't changed.
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*
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* <p>Note that this servlet will apply the last-modified timestamp if you
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* tell it to do so: It's your decision whether the content of the target
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* resource can be cached in such a fashion. Typical use cases are helper
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* resources that are not fronted by a controller, like JavaScript files
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* that are generated by a JSP (without depending on the HttpSession).
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*
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* @author Juergen Hoeller
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* @author Rod Johnson
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* @see #setDefaultUrl
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* @see #setAllowedResources
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* @see #setApplyLastModified
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*/
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@SuppressWarnings("serial")
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public class ResourceServlet extends HttpServletBean {
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/**
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* Any number of these characters are considered delimiters
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* between multiple resource paths in a single String value.
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*/
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public static final String RESOURCE_URL_DELIMITERS = ",; \t\n";
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/**
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* Name of the parameter that must contain the actual resource path.
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*/
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public static final String RESOURCE_PARAM_NAME = "resource";
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@Nullable
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private String defaultUrl;
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@Nullable
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private String allowedResources;
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@Nullable
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private String contentType;
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private boolean applyLastModified = false;
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@Nullable
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private PathMatcher pathMatcher;
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private long startupTime;
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/**
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* Set the URL within the current web application from which to
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* include content if the requested path isn't found, or if none
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* is specified in the first place.
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* <p>If specifying multiple URLs, they will be included one by one
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* to build the response. If last-modified determination is active,
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* the newest timestamp among those files will be used.
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* @see #setApplyLastModified
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*/
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public void setDefaultUrl(String defaultUrl) {
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this.defaultUrl = defaultUrl;
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}
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/**
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* Set allowed resources as URL pattern, e.g. "/WEB-INF/res/*.jsp",
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* The parameter can be any Ant-style pattern parsable by AntPathMatcher.
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* @see org.springframework.util.AntPathMatcher
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*/
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public void setAllowedResources(String allowedResources) {
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this.allowedResources = allowedResources;
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}
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/**
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* Set the content type of the target resource (typically a JSP).
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* Default is none, which is appropriate when including resources.
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* <p>For directly accessing resources, for example to leverage this
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* servlet's last-modified support, specify a content type here.
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* Note that a content type header in the target JSP will be ignored
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* when including the resource via a RequestDispatcher include.
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*/
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public void setContentType(String contentType) {
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this.contentType = contentType;
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}
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/**
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* Set whether to apply the file timestamp of the target resource
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* as last-modified value. Default is "false".
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* <p>This is mainly intended for JSP targets that don't generate
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* session-specific or database-driven content: Such files can be
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* cached by the browser as long as the last-modified timestamp
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* of the JSP file doesn't change.
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* <p>This will only work correctly with expanded WAR files that
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* allow access to the file timestamps. Else, the startup time
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* of this servlet is returned.
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*/
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public void setApplyLastModified(boolean applyLastModified) {
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this.applyLastModified = applyLastModified;
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}
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/**
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* Remember the startup time, using no last-modified time before it.
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*/
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@Override
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protected void initServletBean() {
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this.pathMatcher = getPathMatcher();
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this.startupTime = System.currentTimeMillis();
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}
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/**
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* Return a PathMatcher to use for matching the "allowedResources" URL pattern.
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* Default is AntPathMatcher.
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* @see #setAllowedResources
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* @see org.springframework.util.AntPathMatcher
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*/
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protected PathMatcher getPathMatcher() {
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return new AntPathMatcher();
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}
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/**
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* Determine the URL of the target resource and include it.
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* @see #determineResourceUrl
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*/
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@Override
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protected final void doGet(HttpServletRequest request, HttpServletResponse response)
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throws ServletException, IOException {
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// determine URL of resource to include
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String resourceUrl = determineResourceUrl(request);
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if (resourceUrl != null) {
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try {
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doInclude(request, response, resourceUrl);
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}
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catch (ServletException | IOException ex) {
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if (logger.isWarnEnabled()) {
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logger.warn("Failed to include content of resource [" + resourceUrl + "]", ex);
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}
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// Try including default URL if appropriate.
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if (!includeDefaultUrl(request, response)) {
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throw ex;
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}
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}
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}
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// no resource URL specified -> try to include default URL.
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else if (!includeDefaultUrl(request, response)) {
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throw new ServletException("No target resource URL found for request");
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}
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}
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/**
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* Determine the URL of the target resource of this request.
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* <p>Default implementation returns the value of the "resource" parameter.
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* Can be overridden in subclasses.
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* @param request current HTTP request
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* @return the URL of the target resource, or {@code null} if none found
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* @see #RESOURCE_PARAM_NAME
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*/
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@Nullable
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protected String determineResourceUrl(HttpServletRequest request) {
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return request.getParameter(RESOURCE_PARAM_NAME);
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}
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/**
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* Include the specified default URL, if appropriate.
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* @param request current HTTP request
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* @param response current HTTP response
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* @return whether a default URL was included
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* @throws ServletException if thrown by the RequestDispatcher
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* @throws IOException if thrown by the RequestDispatcher
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*/
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private boolean includeDefaultUrl(HttpServletRequest request, HttpServletResponse response)
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throws ServletException, IOException {
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if (this.defaultUrl == null) {
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return false;
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}
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doInclude(request, response, this.defaultUrl);
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return true;
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}
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/**
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* Include the specified resource via the RequestDispatcher.
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* @param request current HTTP request
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* @param response current HTTP response
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* @param resourceUrl the URL of the target resource
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* @throws ServletException if thrown by the RequestDispatcher
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* @throws IOException if thrown by the RequestDispatcher
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*/
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private void doInclude(HttpServletRequest request, HttpServletResponse response, String resourceUrl)
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throws ServletException, IOException {
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if (this.contentType != null) {
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response.setContentType(this.contentType);
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}
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String[] resourceUrls =
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StringUtils.tokenizeToStringArray(resourceUrl, RESOURCE_URL_DELIMITERS);
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for (String url : resourceUrls) {
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// check whether URL matches allowed resources
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if (this.allowedResources != null) {
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Assert.state(this.pathMatcher != null, "No PathMatcher available");
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if (!this.pathMatcher.match(this.allowedResources, url)) {
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throw new ServletException("Resource [" + url +
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"] does not match allowed pattern [" + this.allowedResources + "]");
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}
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}
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if (logger.isDebugEnabled()) {
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logger.debug("Including resource [" + url + "]");
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}
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RequestDispatcher rd = request.getRequestDispatcher(url);
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rd.include(request, response);
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}
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}
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/**
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* Return the last-modified timestamp of the file that corresponds
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* to the target resource URL (i.e. typically the request ".jsp" file).
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* Will simply return -1 if "applyLastModified" is false (the default).
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* <p>Returns no last-modified date before the startup time of this servlet,
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* to allow for message resolution etc that influences JSP contents,
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* assuming that those background resources might have changed on restart.
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* <p>Returns the startup time of this servlet if the file that corresponds
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* to the target resource URL couldn't be resolved (for example, because
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* the WAR is not expanded).
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* @see #determineResourceUrl
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* @see #getFileTimestamp
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*/
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@Override
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protected final long getLastModified(HttpServletRequest request) {
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if (this.applyLastModified) {
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String resourceUrl = determineResourceUrl(request);
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if (resourceUrl == null) {
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resourceUrl = this.defaultUrl;
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}
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if (resourceUrl != null) {
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String[] resourceUrls = StringUtils.tokenizeToStringArray(resourceUrl, RESOURCE_URL_DELIMITERS);
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long latestTimestamp = -1;
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for (String url : resourceUrls) {
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long timestamp = getFileTimestamp(url);
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if (timestamp > latestTimestamp) {
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latestTimestamp = timestamp;
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}
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}
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return (latestTimestamp > this.startupTime ? latestTimestamp : this.startupTime);
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}
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}
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return -1;
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}
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/**
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* Return the file timestamp for the given resource.
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* @param resourceUrl the URL of the resource
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* @return the file timestamp in milliseconds, or -1 if not determinable
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*/
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protected long getFileTimestamp(String resourceUrl) {
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ServletContextResource resource = new ServletContextResource(getServletContext(), resourceUrl);
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try {
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long lastModifiedTime = resource.lastModified();
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if (logger.isDebugEnabled()) {
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logger.debug("Last-modified timestamp of " + resource + " is " + lastModifiedTime);
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}
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return lastModifiedTime;
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}
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catch (IOException ex) {
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logger.warn("Couldn't retrieve last-modified timestamp of [" + resource +
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"] - using ResourceServlet startup time");
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return -1;
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}
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}
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}
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