org.springframework.web.servlet.mvc.UrlFilenameViewController Maven / Gradle / Ivy
/*
* Copyright 2002-2020 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.web.servlet.mvc;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import javax.servlet.http.HttpServletRequest;
import org.springframework.lang.Nullable;
import org.springframework.util.StringUtils;
import org.springframework.web.servlet.HandlerMapping;
/**
* Simple {@code Controller} implementation that transforms the virtual
* path of a URL into a view name and returns that view.
*
* Can optionally prepend a {@link #setPrefix prefix} and/or append a
* {@link #setSuffix suffix} to build the viewname from the URL filename.
*
*
Find some examples below:
*
* - {@code "/index" -> "index"}
* - {@code "/index.html" -> "index"}
* - {@code "/index.html"} + prefix {@code "pre_"} and suffix {@code "_suf" -> "pre_index_suf"}
* - {@code "/products/view.html" -> "products/view"}
*
*
* Thanks to David Barri for suggesting prefix/suffix support!
*
* @author Alef Arendsen
* @author Juergen Hoeller
* @author Rob Harrop
* @see #setPrefix
* @see #setSuffix
*/
public class UrlFilenameViewController extends AbstractUrlViewController {
private String prefix = "";
private String suffix = "";
/** Request URL path String to view name String. */
private final Map viewNameCache = new ConcurrentHashMap<>(256);
/**
* Set the prefix to prepend to the request URL filename
* to build a view name.
*/
public void setPrefix(@Nullable String prefix) {
this.prefix = (prefix != null ? prefix : "");
}
/**
* Return the prefix to prepend to the request URL filename.
*/
protected String getPrefix() {
return this.prefix;
}
/**
* Set the suffix to append to the request URL filename
* to build a view name.
*/
public void setSuffix(@Nullable String suffix) {
this.suffix = (suffix != null ? suffix : "");
}
/**
* Return the suffix to append to the request URL filename.
*/
protected String getSuffix() {
return this.suffix;
}
/**
* Returns view name based on the URL filename,
* with prefix/suffix applied when appropriate.
* @see #extractViewNameFromUrlPath
* @see #setPrefix
* @see #setSuffix
*/
@Override
protected String getViewNameForRequest(HttpServletRequest request) {
String uri = extractOperableUrl(request);
return getViewNameForUrlPath(uri);
}
/**
* Extract a URL path from the given request,
* suitable for view name extraction.
* @param request current HTTP request
* @return the URL to use for view name extraction
*/
protected String extractOperableUrl(HttpServletRequest request) {
String urlPath = (String) request.getAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE);
if (!StringUtils.hasText(urlPath)) {
urlPath = getUrlPathHelper().getLookupPathForRequest(request, HandlerMapping.LOOKUP_PATH);
}
return urlPath;
}
/**
* Returns view name based on the URL filename,
* with prefix/suffix applied when appropriate.
* @param uri the request URI; for example {@code "/index.html"}
* @return the extracted URI filename; for example {@code "index"}
* @see #extractViewNameFromUrlPath
* @see #postProcessViewName
*/
protected String getViewNameForUrlPath(String uri) {
return this.viewNameCache.computeIfAbsent(uri, u -> postProcessViewName(extractViewNameFromUrlPath(u)));
}
/**
* Extract the URL filename from the given request URI.
* @param uri the request URI; for example {@code "/index.html"}
* @return the extracted URI filename; for example {@code "index"}
*/
protected String extractViewNameFromUrlPath(String uri) {
int start = (uri.charAt(0) == '/' ? 1 : 0);
int lastIndex = uri.lastIndexOf('.');
int end = (lastIndex < 0 ? uri.length() : lastIndex);
return uri.substring(start, end);
}
/**
* Build the full view name based on the given view name
* as indicated by the URL path.
* The default implementation simply applies prefix and suffix.
* This can be overridden, for example, to manipulate upper case
* / lower case, etc.
* @param viewName the original view name, as indicated by the URL path
* @return the full view name to use
* @see #getPrefix()
* @see #getSuffix()
*/
protected String postProcessViewName(String viewName) {
return getPrefix() + viewName + getSuffix();
}
}