org.springframework.web.servlet.view.XmlViewResolver Maven / Gradle / Ivy
/*
* Copyright 2002-2018 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.view;
import java.util.Locale;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.beans.factory.xml.ResourceEntityResolver;
import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.core.Ordered;
import org.springframework.core.io.Resource;
import org.springframework.lang.Nullable;
import org.springframework.web.context.support.GenericWebApplicationContext;
import org.springframework.web.servlet.View;
/**
* A {@link org.springframework.web.servlet.ViewResolver} implementation that uses
* bean definitions in a dedicated XML file for view definitions, specified by
* resource location. The file will typically be located in the WEB-INF directory;
* the default is "/WEB-INF/views.xml".
*
* This {@code ViewResolver} does not support internationalization at the level
* of its definition resources. Consider {@link ResourceBundleViewResolver} if you
* need to apply different view resources per locale.
*
*
Note: This {@code ViewResolver} implements the {@link Ordered} interface
* in order to allow for flexible participation in {@code ViewResolver} chaining.
* For example, some special views could be defined via this {@code ViewResolver}
* (giving it 0 as "order" value), while all remaining views could be resolved by
* a {@link UrlBasedViewResolver}.
*
* @author Juergen Hoeller
* @since 18.06.2003
* @see org.springframework.context.ApplicationContext#getResource
* @see ResourceBundleViewResolver
* @see UrlBasedViewResolver
*/
public class XmlViewResolver extends AbstractCachingViewResolver
implements Ordered, InitializingBean, DisposableBean {
/** Default if no other location is supplied. */
public static final String DEFAULT_LOCATION = "/WEB-INF/views.xml";
@Nullable
private Resource location;
@Nullable
private ConfigurableApplicationContext cachedFactory;
private int order = Ordered.LOWEST_PRECEDENCE; // default: same as non-Ordered
/**
* Set the location of the XML file that defines the view beans.
*
The default is "/WEB-INF/views.xml".
* @param location the location of the XML file.
*/
public void setLocation(Resource location) {
this.location = location;
}
/**
* Specify the order value for this ViewResolver bean.
*
The default value is {@code Ordered.LOWEST_PRECEDENCE}, meaning non-ordered.
* @see org.springframework.core.Ordered#getOrder()
*/
public void setOrder(int order) {
this.order = order;
}
@Override
public int getOrder() {
return this.order;
}
/**
* Pre-initialize the factory from the XML file.
* Only effective if caching is enabled.
*/
@Override
public void afterPropertiesSet() throws BeansException {
if (isCache()) {
initFactory();
}
}
/**
* This implementation returns just the view name,
* as XmlViewResolver doesn't support localized resolution.
*/
@Override
protected Object getCacheKey(String viewName, Locale locale) {
return viewName;
}
@Override
protected View loadView(String viewName, Locale locale) throws BeansException {
BeanFactory factory = initFactory();
try {
return factory.getBean(viewName, View.class);
}
catch (NoSuchBeanDefinitionException ex) {
// Allow for ViewResolver chaining...
return null;
}
}
/**
* Initialize the view bean factory from the XML file.
* Synchronized because of access by parallel threads.
* @throws BeansException in case of initialization errors
*/
protected synchronized BeanFactory initFactory() throws BeansException {
if (this.cachedFactory != null) {
return this.cachedFactory;
}
ApplicationContext applicationContext = obtainApplicationContext();
Resource actualLocation = this.location;
if (actualLocation == null) {
actualLocation = applicationContext.getResource(DEFAULT_LOCATION);
}
// Create child ApplicationContext for views.
GenericWebApplicationContext factory = new GenericWebApplicationContext();
factory.setParent(applicationContext);
factory.setServletContext(getServletContext());
// Load XML resource with context-aware entity resolver.
XmlBeanDefinitionReader reader = new XmlBeanDefinitionReader(factory);
reader.setEnvironment(applicationContext.getEnvironment());
reader.setEntityResolver(new ResourceEntityResolver(applicationContext));
reader.loadBeanDefinitions(actualLocation);
factory.refresh();
if (isCache()) {
this.cachedFactory = factory;
}
return factory;
}
/**
* Close the view bean factory on context shutdown.
*/
@Override
public void destroy() throws BeansException {
if (this.cachedFactory != null) {
this.cachedFactory.close();
}
}
}