org.springframework.web.servlet.view.UrlBasedViewResolver Maven / Gradle / Ivy
/*
* Copyright 2002-2004 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
*
* http://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.view;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;
import java.util.Properties;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.BeansException;
import org.springframework.web.servlet.View;
/**
* Simple implementation of ViewResolver that allows for direct resolution of
* symbolic view names to URLs, without explicit mapping definition. This is
* appropriate if your symbolic names match the names of your view resources
* in a straightforward manner, without the need for arbitrary mappings.
*
* Supports AbstractUrlBasedView subclasses like InternalResourceView,
* VelocityView and FreeMarkerView. The view class for all views generated
* by this resolver can be specified via the "viewClass" property.
*
*
View names can either be resource URLs themselves, or get augmented by a
* specified prefix and/or suffix. Exporting an attribute that holds the
* RequestContext to all views is explicitly supported.
*
*
Example: prefix="/WEB-INF/jsp/", suffix=".jsp", viewname="test" ->
* "/WEB-INF/jsp/test.jsp"
*
*
As a special feature, redirect URLs can be specified via the "redirect:"
* prefix. E.g.: "redirect:myAction.do" will trigger a redirect to the given
* URL, rather than resolution as standard view name. This is typically used
* for redirecting to a controller URL after finishing a form workflow.
*
*
Furthermore, forward URLs can be specified via the "forward:" prefix. E.g.:
* "forward:myAction.do" will trigger a forward to the given URL, rather than
* resolution as standard view name. This is typically used for controller URLs;
* it is not supposed to be used for JSP URLs - use logical view names there.
*
*
Note: This class does not support localized resolution, i.e. resolving
* a symbolic view name to different resources depending on the current locale.
*
*
Note: When chaining ViewResolvers, a UrlBasedViewResolver always needs
* to be last, as it will attempt to resolve any view name, no matter whether
* the underlying resource actually exists.
*
* @author Juergen Hoeller
* @since 13.12.2003
* @see #setViewClass
* @see #setPrefix
* @see #setSuffix
* @see #setRequestContextAttribute
* @see #REDIRECT_URL_PREFIX
* @see AbstractUrlBasedView
* @see InternalResourceView
* @see org.springframework.web.servlet.view.velocity.VelocityView
* @see org.springframework.web.servlet.view.freemarker.FreeMarkerView
*/
public class UrlBasedViewResolver extends AbstractCachingViewResolver {
/**
* Prefix for special view names that specify a redirect URL (usually
* to a controller after a form has been submitted and processed).
* Such view names will not be resolved in the configured default
* way but rather be treated as special shortcut.
*/
public static final String REDIRECT_URL_PREFIX = "redirect:";
/**
* Prefix for special view names that specify a forward URL (usually
* to a controller after a form has been submitted and processed).
* Such view names will not be resolved in the configured default
* way but rather be treated as special shortcut.
*/
public static final String FORWARD_URL_PREFIX = "forward:";
private Class viewClass;
private String prefix = "";
private String suffix = "";
private String contentType;
private boolean redirectContextRelative = true;
private boolean redirectHttp10Compatible = true;
private String requestContextAttribute;
/** Map of static attributes, keyed by attribute name (String) */
private final Map staticAttributes = new HashMap();
/**
* Set the view class that should be used to create views.
* @param viewClass class that is assignable to the required view class
* (by default, AbstractUrlBasedView)
* @see AbstractUrlBasedView
*/
public void setViewClass(Class viewClass) {
if (viewClass == null || !requiredViewClass().isAssignableFrom(viewClass)) {
throw new IllegalArgumentException(
"Given view class [" + (viewClass != null ? viewClass.getName() : null) +
"] is not of type [" + requiredViewClass().getName() + "]");
}
this.viewClass = viewClass;
}
/**
* Return the required type of view for this resolver.
* This implementation returns AbstractUrlBasedView.
* @see AbstractUrlBasedView
*/
protected Class requiredViewClass() {
return AbstractUrlBasedView.class;
}
/**
* Set the prefix that gets applied to view names when building a URL.
* @param prefix view name prefix
*/
public void setPrefix(String prefix) {
this.prefix = prefix;
}
/**
* Set the suffix that gets applied to view names when building a URL.
* @param suffix view name suffix
*/
public void setSuffix(String suffix) {
this.suffix = suffix;
}
/**
* Set the content type for all views.
* May be ignored by view classes if the view itself is assumed
* to set the content type, e.g. in case of JSPs.
* @param contentType the content type
*/
public void setContentType(String contentType) {
this.contentType = contentType;
}
/**
* Set whether to interpret a given redirect URL that starts with a
* slash ("/") as relative to the current ServletContext, i.e. as
* relative to the web application root.
*
Default is true: A redirect URL that starts with a slash will be
* interpreted as relative to the web application root, i.e. the context
* path will be prepended to the URL.
*
Redirect URLs can be specified via the "redirect:" prefix.
* E.g.: "redirect:myAction.do"
* @see RedirectView#setContextRelative
* @see #REDIRECT_URL_PREFIX
*/
public void setRedirectContextRelative(boolean redirectContextRelative) {
this.redirectContextRelative = redirectContextRelative;
}
/**
* Set whether redirects should stay compatible with HTTP 1.0 clients.
*
In the default implementation, this will enforce HTTP status code 302
* in any case, i.e. delegate to HttpServletResponse.sendRedirect.
* Turning this off will send HTTP status code 303, which is the correct
* code for HTTP 1.1 clients, but not understood by HTTP 1.0 clients.
*
Many HTTP 1.1 clients treat 302 just like 303, not making any
* difference. However, some clients depend on 303 when redirecting
* after a POST request; turn this flag off in such a scenario.
*
Redirect URLs can be specified via the "redirect:" prefix.
* E.g.: "redirect:myAction.do"
* @see RedirectView#setHttp10Compatible
* @see #REDIRECT_URL_PREFIX
*/
public void setRedirectHttp10Compatible(boolean redirectHttp10Compatible) {
this.redirectHttp10Compatible = redirectHttp10Compatible;
}
/**
* Set the name of the RequestContext attribute for all views.
* @param requestContextAttribute name of the RequestContext attribute
* @see AbstractView#setRequestContextAttribute
*/
public void setRequestContextAttribute(String requestContextAttribute) {
this.requestContextAttribute = requestContextAttribute;
}
/**
* Set static attributes from a java.util.Properties object,
* for all views returned by this resolver.
*
This is the most convenient way to set static attributes. Note that
* static attributes can be overridden by dynamic attributes, if a value
* with the same name is included in the model.
*
Can be populated with a String "value" (parsed via PropertiesEditor)
* or a "props" element in XML bean definitions.
* @see org.springframework.beans.propertyeditors.PropertiesEditor
* @see AbstractView#setAttributes
*/
public void setAttributes(Properties props) {
setAttributesMap(props);
}
/**
* Set static attributes from a Map, for all views returned by this resolver.
* This allows to set any kind of attribute values, for example bean references.
*
Can be populated with a "map" or "props" element in XML bean definitions.
* @param attributes Map with name Strings as keys and attribute objects as values
* @see AbstractView#setAttributesMap
*/
public void setAttributesMap(Map attributes) {
if (attributes != null) {
this.staticAttributes.putAll(attributes);
}
}
/**
* Allow Map access to the static attributes for views returned by
* this resolver, with the option to add or override specific entries.
*
Useful for specifying entries directly, for example via
* "attributesMap[myKey]". This is particularly useful for
* adding or overriding entries in child view definitions.
*/
public Map getAttributesMap() {
return this.staticAttributes;
}
protected void initApplicationContext() {
super.initApplicationContext();
if (this.viewClass == null) {
throw new IllegalArgumentException("viewClass is required");
}
}
/**
* This implementation returns just the view name,
* as this ViewResolver doesn't support localized resolution.
*/
protected String getCacheKey(String viewName, Locale locale) {
return viewName;
}
/**
* Overridden to implement check for "redirect:" prefix.
*
Not possible in loadView, as overridden loadView versions in
* subclasses might rely on the superclass always creating instances
* of the required view class.
* @see #loadView
* @see #requiredViewClass
*/
protected View createView(String viewName, Locale locale) throws Exception {
// Check for special "redirect:" prefix.
if (viewName.startsWith(REDIRECT_URL_PREFIX)) {
String redirectUrl = viewName.substring(REDIRECT_URL_PREFIX.length());
return new RedirectView(
redirectUrl, this.redirectContextRelative, this.redirectHttp10Compatible);
}
// Check for special "forward:" prefix.
if (viewName.startsWith(FORWARD_URL_PREFIX)) {
String forwardUrl = viewName.substring(FORWARD_URL_PREFIX.length());
return new InternalResourceView(forwardUrl);
}
// Else fall back to superclass implementation: calling loadView.
return super.createView(viewName, locale);
}
/**
* Creates a new instance of the specified view class and configures it.
* Does not perform any lookup for pre-defined View instances.
*/
protected View loadView(String viewName, Locale locale) throws BeansException {
AbstractUrlBasedView view = (AbstractUrlBasedView) BeanUtils.instantiateClass(this.viewClass);
view.setBeanName(viewName);
view.setUrl(this.prefix + viewName + this.suffix);
if (this.contentType != null) {
view.setContentType(this.contentType);
}
view.setRequestContextAttribute(this.requestContextAttribute);
view.setAttributesMap(this.staticAttributes);
return view;
}
}