org.springframework.web.servlet.DispatcherServlet Maven / Gradle / Ivy
/*
* Copyright 2002-2007 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;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactoryUtils;
import org.springframework.beans.factory.BeanInitializationException;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.beans.factory.config.AutowireCapableBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.i18n.LocaleContext;
import org.springframework.context.i18n.LocaleContextHolder;
import org.springframework.core.OrderComparator;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.support.PropertiesLoaderUtils;
import org.springframework.ui.context.ThemeSource;
import org.springframework.util.ClassUtils;
import org.springframework.util.StringUtils;
import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import org.springframework.web.multipart.MultipartException;
import org.springframework.web.multipart.MultipartHttpServletRequest;
import org.springframework.web.multipart.MultipartResolver;
import org.springframework.web.util.NestedServletException;
import org.springframework.web.util.UrlPathHelper;
import org.springframework.web.util.WebUtils;
/**
* Central dispatcher for HTTP request handlers/controllers,
* e.g. for web UI controllers or HTTP-based remote service exporters.
* Dispatches to registered handlers for processing a web request,
* providing convenient mapping and exception handling facilities.
*
* This servlet is very flexible: It can be used with just about any workflow,
* with the installation of the appropriate adapter classes. It offers the
* following functionality that distinguishes it from other request-driven
* web MVC frameworks:
*
*
* - It is based around a JavaBeans configuration mechanism.
*
*
- It can use any {@link HandlerMapping} implementation - pre-built or provided
* as part of an application - to control the routing of requests to handler objects.
* Default is {@link org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping}.
* HandlerMapping objects can be defined as beans in the servlet's application context,
* implementing the HandlerMapping interface, overriding the default HandlerMapping
* if present. HandlerMappings can be given any bean name (they are tested by type).
*
*
- It can use any {@link HandlerAdapter}; this allows to use any handler interface.
* Default adapters are {@link org.springframework.web.servlet.mvc.HttpRequestHandlerAdapter},
* {@link org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter} and
* {@link org.springframework.web.servlet.mvc.throwaway.ThrowawayControllerHandlerAdapter},
* for Spring's {@link org.springframework.web.HttpRequestHandler},
* {@link org.springframework.web.servlet.mvc.Controller} and
* {@link org.springframework.web.servlet.mvc.throwaway.ThrowawayController} interfaces,
* respectively. HandlerAdapter objects can be added as beans in the application context,
* overriding the default HandlerAdapters. Like HandlerMappings, HandlerAdapters
* can be given any bean name (they are tested by type).
*
*
- The dispatcher's exception resolution strategy can be specified via a
* {@link HandlerExceptionResolver}, for example mapping certain exceptions to
* error pages. Default is none. Additional HandlerExceptionResolvers can be added
* through the application context. HandlerExceptionResolver can be given any
* bean name (they are tested by type).
*
*
- Its view resolution strategy can be specified via a {@link ViewResolver}
* implementation, resolving symbolic view names into View objects. Default is
* {@link org.springframework.web.servlet.view.InternalResourceViewResolver}.
* ViewResolver objects can be added as beans in the application context,
* overriding the default ViewResolver. ViewResolvers can be given any bean name
* (they are tested by type).
*
*
- If a {@link View} or view name is not supplied by the user, then the configured
* {@link RequestToViewNameTranslator} will translate the current request into a
* view name. The corresponding bean name is "viewNameTranslator"; the default is
* {@link org.springframework.web.servlet.view.DefaultRequestToViewNameTranslator}.
*
*
- The dispatcher's strategy for resolving multipart requests is determined by
* a {@link org.springframework.web.multipart.MultipartResolver} implementation.
* Implementations for Jakarta Commons FileUpload and Jason Hunter's COS are
* included; the typical choise is
* {@link org.springframework.web.multipart.commons.CommonsMultipartResolver}.
* The MultipartResolver bean name is "multipartResolver"; default is none.
*
*
- Its locale resolution strategy is determined by a {@link LocaleResolver}.
* Out-of-the-box implementations work via HTTP accept header, cookie, or session.
* The LocaleResolver bean name is "localeResolver"; default is
* {@link org.springframework.web.servlet.i18n.AcceptHeaderLocaleResolver}.
*
*
- Its theme resolution strategy is determined by a {@link ThemeResolver}.
* Implementations for a fixed theme and for cookie and session storage are included.
* The ThemeResolver bean name is "themeResolver"; default is
* {@link org.springframework.web.servlet.theme.FixedThemeResolver}.
*
*
* A web application can define any number of DispatcherServlets.
* Each servlet will operate in its own namespace, loading its own application
* context with mappings, handlers, etc. Only the root application context
* as loaded by {@link org.springframework.web.context.ContextLoaderListener},
* if any, will be shared.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @author Rob Harrop
* @see org.springframework.web.HttpRequestHandler
* @see org.springframework.web.servlet.mvc.Controller
* @see org.springframework.web.context.ContextLoaderListener
*/
public class DispatcherServlet extends FrameworkServlet {
/**
* Well-known name for the MultipartResolver object in the bean factory for this namespace.
*/
public static final String MULTIPART_RESOLVER_BEAN_NAME = "multipartResolver";
/**
* Well-known name for the LocaleResolver object in the bean factory for this namespace.
*/
public static final String LOCALE_RESOLVER_BEAN_NAME = "localeResolver";
/**
* Well-known name for the ThemeResolver object in the bean factory for this namespace.
*/
public static final String THEME_RESOLVER_BEAN_NAME = "themeResolver";
/**
* Well-known name for the HandlerMapping object in the bean factory for this namespace.
* Only used when "detectAllHandlerMappings" is turned off.
* @see #setDetectAllHandlerMappings
*/
public static final String HANDLER_MAPPING_BEAN_NAME = "handlerMapping";
/**
* Well-known name for the HandlerAdapter object in the bean factory for this namespace.
* Only used when "detectAllHandlerAdapters" is turned off.
* @see #setDetectAllHandlerAdapters
*/
public static final String HANDLER_ADAPTER_BEAN_NAME = "handlerAdapter";
/**
* Well-known name for the HandlerExceptionResolver object in the bean factory for this
* namespace. Only used when "detectAllHandlerExceptionResolvers" is turned off.
* @see #setDetectAllHandlerExceptionResolvers
*/
public static final String HANDLER_EXCEPTION_RESOLVER_BEAN_NAME = "handlerExceptionResolver";
/**
* Well-known name for the RequestToViewNameTranslator object in the bean factory for
* this namespace.
*/
public static final String REQUEST_TO_VIEW_NAME_TRANSLATOR_BEAN_NAME = "viewNameTranslator";
/**
* Well-known name for the ViewResolver object in the bean factory for this namespace.
* Only used when "detectAllViewResolvers" is turned off.
* @see #setDetectAllViewResolvers
*/
public static final String VIEW_RESOLVER_BEAN_NAME = "viewResolver";
/**
* Request attribute to hold the currently chosen HandlerExecutionChain.
* Only used for internal optimizations.
*/
public static final String HANDLER_EXECUTION_CHAIN_ATTRIBUTE = DispatcherServlet.class.getName() + ".HANDLER";
/**
* Request attribute to hold the current web application context.
* Otherwise only the global web app context is obtainable by tags etc.
* @see org.springframework.web.servlet.support.RequestContextUtils#getWebApplicationContext
*/
public static final String WEB_APPLICATION_CONTEXT_ATTRIBUTE = DispatcherServlet.class.getName() + ".CONTEXT";
/**
* Request attribute to hold the current LocaleResolver, retrievable by views.
* @see org.springframework.web.servlet.support.RequestContextUtils#getLocaleResolver
*/
public static final String LOCALE_RESOLVER_ATTRIBUTE = DispatcherServlet.class.getName() + ".LOCALE_RESOLVER";
/**
* Request attribute to hold the current ThemeResolver, retrievable by views.
* @see org.springframework.web.servlet.support.RequestContextUtils#getThemeResolver
*/
public static final String THEME_RESOLVER_ATTRIBUTE = DispatcherServlet.class.getName() + ".THEME_RESOLVER";
/**
* Request attribute to hold the current ThemeSource, retrievable by views.
* @see org.springframework.web.servlet.support.RequestContextUtils#getThemeSource
*/
public static final String THEME_SOURCE_ATTRIBUTE = DispatcherServlet.class.getName() + ".THEME_SOURCE";
/**
* Log category to use when no mapped handler is found for a request.
*/
public static final String PAGE_NOT_FOUND_LOG_CATEGORY = "org.springframework.web.servlet.PageNotFound";
/**
* Name of the class path resource (relative to the DispatcherServlet class)
* that defines DispatcherServlet's default strategy names.
*/
private static final String DEFAULT_STRATEGIES_PATH = "DispatcherServlet.properties";
/**
* Additional logger to use when no mapped handler is found for a request.
*/
protected static final Log pageNotFoundLogger = LogFactory.getLog(PAGE_NOT_FOUND_LOG_CATEGORY);
private static final Properties defaultStrategies;
static {
// Load default strategy implementations from properties file.
// This is currently strictly internal and not meant to be customized
// by application developers.
try {
ClassPathResource resource = new ClassPathResource(DEFAULT_STRATEGIES_PATH, DispatcherServlet.class);
defaultStrategies = PropertiesLoaderUtils.loadProperties(resource);
}
catch (IOException ex) {
throw new IllegalStateException("Could not load 'DispatcherServlet.properties': " + ex.getMessage());
}
}
/** Detect all HandlerMappings or just expect "handlerMapping" bean? */
private boolean detectAllHandlerMappings = true;
/** Detect all HandlerAdapters or just expect "handlerAdapter" bean? */
private boolean detectAllHandlerAdapters = true;
/** Detect all HandlerExceptionResolvers or just expect "handlerExceptionResolver" bean? */
private boolean detectAllHandlerExceptionResolvers = true;
/** Detect all ViewResolvers or just expect "viewResolver" bean? */
private boolean detectAllViewResolvers = true;
/** Perform cleanup of request attributes after include request? */
private boolean cleanupAfterInclude = true;
/** Expose LocaleContext and RequestAttributes as inheritable for child threads? */
private boolean threadContextInheritable = false;
/** MultipartResolver used by this servlet */
private MultipartResolver multipartResolver;
/** LocaleResolver used by this servlet */
private LocaleResolver localeResolver;
/** ThemeResolver used by this servlet */
private ThemeResolver themeResolver;
/** List of HandlerMappings used by this servlet */
private List handlerMappings;
/** List of HandlerAdapters used by this servlet */
private List handlerAdapters;
/** List of HandlerExceptionResolvers used by this servlet */
private List handlerExceptionResolvers;
/** RequestToViewNameTranslator used by this servlet */
private RequestToViewNameTranslator viewNameTranslator;
/** List of ViewResolvers used by this servlet */
private List viewResolvers;
/**
* Set whether to detect all HandlerMapping beans in this servlet's context.
* Else, just a single bean with name "handlerMapping" will be expected.
*
Default is "true". Turn this off if you want this servlet to use a
* single HandlerMapping, despite multiple HandlerMapping beans being
* defined in the context.
*/
public void setDetectAllHandlerMappings(boolean detectAllHandlerMappings) {
this.detectAllHandlerMappings = detectAllHandlerMappings;
}
/**
* Set whether to detect all HandlerAdapter beans in this servlet's context.
* Else, just a single bean with name "handlerAdapter" will be expected.
*
Default is "true". Turn this off if you want this servlet to use a
* single HandlerAdapter, despite multiple HandlerAdapter beans being
* defined in the context.
*/
public void setDetectAllHandlerAdapters(boolean detectAllHandlerAdapters) {
this.detectAllHandlerAdapters = detectAllHandlerAdapters;
}
/**
* Set whether to detect all HandlerExceptionResolver beans in this servlet's context.
* Else, just a single bean with name "handlerExceptionResolver" will be expected.
*
Default is "true". Turn this off if you want this servlet to use a
* single HandlerExceptionResolver, despite multiple HandlerExceptionResolver
* beans being defined in the context.
*/
public void setDetectAllHandlerExceptionResolvers(boolean detectAllHandlerExceptionResolvers) {
this.detectAllHandlerExceptionResolvers = detectAllHandlerExceptionResolvers;
}
/**
* Set whether to detect all ViewResolver beans in this servlet's context.
* Else, just a single bean with name "viewResolver" will be expected.
*
Default is "true". Turn this off if you want this servlet to use a
* single ViewResolver, despite multiple ViewResolver beans being
* defined in the context.
*/
public void setDetectAllViewResolvers(boolean detectAllViewResolvers) {
this.detectAllViewResolvers = detectAllViewResolvers;
}
/**
* Set whether to perform cleanup of request attributes after an include request,
* that is, whether to reset the original state of all request attributes after
* the DispatcherServlet has processed within an include request. Else, just the
* DispatcherServlet's own request attributes will be reset, but not model
* attributes for JSPs or special attributes set by views (for example, JSTL's).
*
Default is "true", which is strongly recommended. Views should not rely on
* request attributes having been set by (dynamic) includes. This allows JSP views
* rendered by an included controller to use any model attributes, even with the
* same names as in the main JSP, without causing side effects. Only turn this
* off for special needs, for example to deliberately allow main JSPs to access
* attributes from JSP views rendered by an included controller.
*/
public void setCleanupAfterInclude(boolean cleanupAfterInclude) {
this.cleanupAfterInclude = cleanupAfterInclude;
}
/**
* Set whether to expose the LocaleContext and RequestAttributes as inheritable
* for child threads (using an {@link java.lang.InheritableThreadLocal}).
*
Default is "false", to avoid side effects on spawned background threads.
* Switch this to "true" to enable inheritance for custom child threads which
* are spawned during request processing and only used for this request
* (that is, ending after their initial task, without reuse of the thread).
*
WARNING: Do not use inheritance for child threads if you are
* accessing a thread pool which is configured to potentially add new threads
* on demand (e.g. a JDK {@link java.util.concurrent.ThreadPoolExecutor}),
* since this will expose the inherited context to such a pooled thread.
*/
public void setThreadContextInheritable(boolean threadContextInheritable) {
this.threadContextInheritable = threadContextInheritable;
}
/**
* This implementation calls {@link #initStrategies}.
*/
protected void onRefresh(ApplicationContext context) throws BeansException {
initStrategies(context);
}
/**
* Initialize the strategy objects that this servlet uses.
*
May be overridden in subclasses in order to initialize
* further strategy objects.
*/
protected void initStrategies(ApplicationContext context) {
initMultipartResolver(context);
initLocaleResolver(context);
initThemeResolver(context);
initHandlerMappings(context);
initHandlerAdapters(context);
initHandlerExceptionResolvers(context);
initRequestToViewNameTranslator(context);
initViewResolvers(context);
}
/**
* Initialize the MultipartResolver used by this class.
*
If no bean is defined with the given name in the BeanFactory
* for this namespace, no multipart handling is provided.
*/
private void initMultipartResolver(ApplicationContext context) {
try {
this.multipartResolver = (MultipartResolver)
context.getBean(MULTIPART_RESOLVER_BEAN_NAME, MultipartResolver.class);
if (logger.isDebugEnabled()) {
logger.debug("Using MultipartResolver [" + this.multipartResolver + "]");
}
}
catch (NoSuchBeanDefinitionException ex) {
// Default is no multipart resolver.
this.multipartResolver = null;
if (logger.isDebugEnabled()) {
logger.debug("Unable to locate MultipartResolver with name '" + MULTIPART_RESOLVER_BEAN_NAME +
"': no multipart request handling provided");
}
}
}
/**
* Initialize the LocaleResolver used by this class.
*
If no bean is defined with the given name in the BeanFactory
* for this namespace, we default to AcceptHeaderLocaleResolver.
*/
private void initLocaleResolver(ApplicationContext context) {
try {
this.localeResolver = (LocaleResolver)
context.getBean(LOCALE_RESOLVER_BEAN_NAME, LocaleResolver.class);
if (logger.isDebugEnabled()) {
logger.debug("Using LocaleResolver [" + this.localeResolver + "]");
}
}
catch (NoSuchBeanDefinitionException ex) {
// We need to use the default.
this.localeResolver = (LocaleResolver) getDefaultStrategy(context, LocaleResolver.class);
if (logger.isDebugEnabled()) {
logger.debug("Unable to locate LocaleResolver with name '" + LOCALE_RESOLVER_BEAN_NAME +
"': using default [" + this.localeResolver + "]");
}
}
}
/**
* Initialize the ThemeResolver used by this class.
*
If no bean is defined with the given name in the BeanFactory
* for this namespace, we default to a FixedThemeResolver.
*/
private void initThemeResolver(ApplicationContext context) {
try {
this.themeResolver = (ThemeResolver)
context.getBean(THEME_RESOLVER_BEAN_NAME, ThemeResolver.class);
if (logger.isDebugEnabled()) {
logger.debug("Using ThemeResolver [" + this.themeResolver + "]");
}
}
catch (NoSuchBeanDefinitionException ex) {
// We need to use the default.
this.themeResolver = (ThemeResolver) getDefaultStrategy(context, ThemeResolver.class);
if (logger.isDebugEnabled()) {
logger.debug("Unable to locate ThemeResolver with name '" + THEME_RESOLVER_BEAN_NAME +
"': using default [" + this.themeResolver + "]");
}
}
}
/**
* Initialize the HandlerMappings used by this class.
*
If no HandlerMapping beans are defined in the BeanFactory
* for this namespace, we default to BeanNameUrlHandlerMapping.
*/
private void initHandlerMappings(ApplicationContext context) {
this.handlerMappings = null;
if (this.detectAllHandlerMappings) {
// Find all HandlerMappings in the ApplicationContext,
// including ancestor contexts.
Map matchingBeans = BeanFactoryUtils.beansOfTypeIncludingAncestors(
context, HandlerMapping.class, true, false);
if (!matchingBeans.isEmpty()) {
this.handlerMappings = new ArrayList(matchingBeans.values());
// We keep HandlerMappings in sorted order.
Collections.sort(this.handlerMappings, new OrderComparator());
}
}
else {
try {
Object hm = context.getBean(HANDLER_MAPPING_BEAN_NAME, HandlerMapping.class);
this.handlerMappings = Collections.singletonList(hm);
}
catch (NoSuchBeanDefinitionException ex) {
// Ignore, we'll add a default HandlerMapping later.
}
}
// Ensure we have at least one HandlerMapping, by registering
// a default HandlerMapping if no other mappings are found.
if (this.handlerMappings == null) {
this.handlerMappings = getDefaultStrategies(context, HandlerMapping.class);
if (logger.isDebugEnabled()) {
logger.debug("No HandlerMappings found in servlet '" + getServletName() + "': using default");
}
}
}
/**
* Initialize the HandlerAdapters used by this class.
*
If no HandlerAdapter beans are defined in the BeanFactory
* for this namespace, we default to SimpleControllerHandlerAdapter.
*/
private void initHandlerAdapters(ApplicationContext context) {
this.handlerAdapters = null;
if (this.detectAllHandlerAdapters) {
// Find all HandlerAdapters in the ApplicationContext,
// including ancestor contexts.
Map matchingBeans = BeanFactoryUtils.beansOfTypeIncludingAncestors(
context, HandlerAdapter.class, true, false);
if (!matchingBeans.isEmpty()) {
this.handlerAdapters = new ArrayList(matchingBeans.values());
// We keep HandlerAdapters in sorted order.
Collections.sort(this.handlerAdapters, new OrderComparator());
}
}
else {
try {
Object ha = context.getBean(HANDLER_ADAPTER_BEAN_NAME, HandlerAdapter.class);
this.handlerAdapters = Collections.singletonList(ha);
}
catch (NoSuchBeanDefinitionException ex) {
// Ignore, we'll add a default HandlerAdapter later.
}
}
// Ensure we have at least some HandlerAdapters, by registering
// default HandlerAdapters if no other adapters are found.
if (this.handlerAdapters == null) {
this.handlerAdapters = getDefaultStrategies(context, HandlerAdapter.class);
if (logger.isDebugEnabled()) {
logger.debug("No HandlerAdapters found in servlet '" + getServletName() + "': using default");
}
}
}
/**
* Initialize the HandlerExceptionResolver used by this class.
*
If no bean is defined with the given name in the BeanFactory
* for this namespace, we default to no exception resolver.
*/
private void initHandlerExceptionResolvers(ApplicationContext context) {
this.handlerExceptionResolvers = null;
if (this.detectAllHandlerExceptionResolvers) {
// Find all HandlerExceptionResolvers in the ApplicationContext,
// including ancestor contexts.
Map matchingBeans = BeanFactoryUtils.beansOfTypeIncludingAncestors(
context, HandlerExceptionResolver.class, true, false);
if (!matchingBeans.isEmpty()) {
this.handlerExceptionResolvers = new ArrayList(matchingBeans.values());
// We keep HandlerExceptionResolvers in sorted order.
Collections.sort(this.handlerExceptionResolvers, new OrderComparator());
}
}
else {
try {
Object her = context.getBean(
HANDLER_EXCEPTION_RESOLVER_BEAN_NAME, HandlerExceptionResolver.class);
this.handlerExceptionResolvers = Collections.singletonList(her);
}
catch (NoSuchBeanDefinitionException ex) {
// Ignore, no HandlerExceptionResolver is fine too.
}
}
// Just for consistency, check for default HandlerExceptionResolvers...
// There aren't any in usual scenarios.
if (this.handlerExceptionResolvers == null) {
this.handlerExceptionResolvers = getDefaultStrategies(context, HandlerExceptionResolver.class);
if (logger.isDebugEnabled()) {
logger.debug("No HandlerExceptionResolvers found in servlet '" + getServletName() + "': using default");
}
}
}
/**
* Initialize the RequestToViewNameTranslator used by this servlet instance. If no
* implementation is configured then we default to DefaultRequestToViewNameTranslator.
*/
private void initRequestToViewNameTranslator(ApplicationContext context) {
try {
this.viewNameTranslator = (RequestToViewNameTranslator) context.getBean(
REQUEST_TO_VIEW_NAME_TRANSLATOR_BEAN_NAME, RequestToViewNameTranslator.class);
if (logger.isDebugEnabled()) {
logger.debug("Using RequestToViewNameTranslator [" + this.viewNameTranslator + "]");
}
}
catch (NoSuchBeanDefinitionException ex) {
// We need to use the default.
this.viewNameTranslator =
(RequestToViewNameTranslator) getDefaultStrategy(context, RequestToViewNameTranslator.class);
if (logger.isDebugEnabled()) {
logger.debug("Unable to locate RequestToViewNameTranslator with name '" +
REQUEST_TO_VIEW_NAME_TRANSLATOR_BEAN_NAME +
"': using default [" + this.viewNameTranslator + "]");
}
}
}
/**
* Initialize the ViewResolvers used by this class.
*
If no ViewResolver beans are defined in the BeanFactory
* for this namespace, we default to InternalResourceViewResolver.
*/
private void initViewResolvers(ApplicationContext context) {
this.viewResolvers = null;
if (this.detectAllViewResolvers) {
// Find all ViewResolvers in the ApplicationContext,
// including ancestor contexts.
Map matchingBeans = BeanFactoryUtils.beansOfTypeIncludingAncestors(
context, ViewResolver.class, true, false);
if (!matchingBeans.isEmpty()) {
this.viewResolvers = new ArrayList(matchingBeans.values());
// We keep ViewResolvers in sorted order.
Collections.sort(this.viewResolvers, new OrderComparator());
}
}
else {
try {
Object vr = context.getBean(VIEW_RESOLVER_BEAN_NAME, ViewResolver.class);
this.viewResolvers = Collections.singletonList(vr);
}
catch (NoSuchBeanDefinitionException ex) {
// Ignore, we'll add a default ViewResolver later.
}
}
// Ensure we have at least one ViewResolver, by registering
// a default ViewResolver if no other resolvers are found.
if (this.viewResolvers == null) {
this.viewResolvers = getDefaultStrategies(context, ViewResolver.class);
if (logger.isDebugEnabled()) {
logger.debug("No ViewResolvers found in servlet '" + getServletName() + "': using default");
}
}
}
/**
* Return this servlet's ThemeSource, if any; else return null.
*
Default is to return the WebApplicationContext as ThemeSource,
* provided that it implements the ThemeSource interface.
* @return the ThemeSource, if any
* @see #getWebApplicationContext()
*/
public ThemeSource getThemeSource() {
if (getWebApplicationContext() instanceof ThemeSource) {
return (ThemeSource) getWebApplicationContext();
}
else {
return null;
}
}
/**
* Return the default strategy object for the given strategy interface.
*
The default implementation delegates to {@link #getDefaultStrategies},
* expecting a single object in the list.
* @param context the current WebApplicationContext
* @param strategyInterface the strategy interface
* @return the corresponding strategy object
* @throws BeansException if initialization failed
* @see #getDefaultStrategies
*/
protected Object getDefaultStrategy(ApplicationContext context, Class strategyInterface) throws BeansException {
List strategies = getDefaultStrategies(context, strategyInterface);
if (strategies.size() != 1) {
throw new BeanInitializationException(
"DispatcherServlet needs exactly 1 strategy for interface [" + strategyInterface.getName() + "]");
}
return strategies.get(0);
}
/**
* Create a List of default strategy objects for the given strategy interface.
*
The default implementation uses the "DispatcherServlet.properties" file
* (in the same package as the DispatcherServlet class) to determine the class names.
* It instantiates the strategy objects through the context's BeanFactory.
* @param context the current WebApplicationContext
* @param strategyInterface the strategy interface
* @return the List of corresponding strategy objects
* @throws BeansException if initialization failed
*/
protected List getDefaultStrategies(ApplicationContext context, Class strategyInterface) throws BeansException {
String key = strategyInterface.getName();
List strategies = null;
String value = defaultStrategies.getProperty(key);
if (value != null) {
String[] classNames = StringUtils.commaDelimitedListToStringArray(value);
strategies = new ArrayList(classNames.length);
for (int i = 0; i < classNames.length; i++) {
String className = classNames[i];
try {
Class clazz = ClassUtils.forName(className, getClass().getClassLoader());
Object strategy = createDefaultStrategy(context, clazz);
strategies.add(strategy);
}
catch (ClassNotFoundException ex) {
throw new BeanInitializationException(
"Could not find DispatcherServlet's default strategy class [" + className +
"] for interface [" + key + "]", ex);
}
catch (LinkageError err) {
throw new BeanInitializationException(
"Error loading DispatcherServlet's default strategy class [" + className +
"] for interface [" + key + "]: problem with class file or dependent class", err);
}
}
}
else {
strategies = Collections.EMPTY_LIST;
}
return strategies;
}
/**
* Create a default strategy.
*
The default implementation uses
* {@link org.springframework.beans.factory.config.AutowireCapableBeanFactory#createBean}.
* @param context the current WebApplicationContext
* @param clazz the strategy implementation class to instantiate
* @throws BeansException if initialization failed
* @return the fully configured strategy instance
* @see org.springframework.context.ApplicationContext#getAutowireCapableBeanFactory()
* @see org.springframework.beans.factory.config.AutowireCapableBeanFactory#createBean
*/
protected Object createDefaultStrategy(ApplicationContext context, Class clazz) throws BeansException {
return context.getAutowireCapableBeanFactory().createBean(
clazz, AutowireCapableBeanFactory.AUTOWIRE_NO, false);
}
/**
* Obtain this servlet's MultipartResolver, if any.
* @return the MultipartResolver used by this servlet, or null
* if none (indicating that no multipart support is available)
*/
public MultipartResolver getMultipartResolver() {
return this.multipartResolver;
}
/**
* Exposes the DispatcherServlet-specific request attributes and
* delegates to {@link #doDispatch} for the actual dispatching.
*/
protected void doService(HttpServletRequest request, HttpServletResponse response) throws Exception {
if (logger.isDebugEnabled()) {
String requestUri = new UrlPathHelper().getRequestUri(request);
logger.debug(
"DispatcherServlet with name '" + getServletName() + "' received request for [" + requestUri + "]");
}
// Keep a snapshot of the request attributes in case of an include,
// to be able to restore the original attributes after the include.
Map attributesSnapshot = null;
if (WebUtils.isIncludeRequest(request)) {
logger.debug("Taking snapshot of request attributes before include");
attributesSnapshot = new HashMap();
Enumeration attrNames = request.getAttributeNames();
while (attrNames.hasMoreElements()) {
String attrName = (String) attrNames.nextElement();
if (this.cleanupAfterInclude || attrName.startsWith(DispatcherServlet.class.getName())) {
attributesSnapshot.put(attrName, request.getAttribute(attrName));
}
}
}
// Make framework objects available to handlers and view objects.
request.setAttribute(WEB_APPLICATION_CONTEXT_ATTRIBUTE, getWebApplicationContext());
request.setAttribute(LOCALE_RESOLVER_ATTRIBUTE, this.localeResolver);
request.setAttribute(THEME_RESOLVER_ATTRIBUTE, this.themeResolver);
request.setAttribute(THEME_SOURCE_ATTRIBUTE, getThemeSource());
try {
doDispatch(request, response);
}
finally {
// Restore the original attribute snapshot, in case of an include.
if (attributesSnapshot != null) {
restoreAttributesAfterInclude(request, attributesSnapshot);
}
}
}
/**
* Process the actual dispatching to the handler.
*
The handler will be obtained by applying the servlet's HandlerMappings in order.
* The HandlerAdapter will be obtained by querying the servlet's installed
* HandlerAdapters to find the first that supports the handler class.
*
All HTTP methods are handled by this method. It's up to HandlerAdapters or
* handlers themselves to decide which methods are acceptable.
* @param request current HTTP request
* @param response current HTTP response
* @throws Exception in case of any kind of processing failure
*/
protected void doDispatch(HttpServletRequest request, HttpServletResponse response) throws Exception {
HttpServletRequest processedRequest = request;
HandlerExecutionChain mappedHandler = null;
int interceptorIndex = -1;
// Expose current LocaleResolver and request as LocaleContext.
LocaleContext previousLocaleContext = LocaleContextHolder.getLocaleContext();
LocaleContextHolder.setLocaleContext(buildLocaleContext(request), this.threadContextInheritable);
// Expose current RequestAttributes to current thread.
RequestAttributes previousRequestAttributes = RequestContextHolder.getRequestAttributes();
ServletRequestAttributes requestAttributes = new ServletRequestAttributes(request);
RequestContextHolder.setRequestAttributes(requestAttributes, this.threadContextInheritable);
if (logger.isDebugEnabled()) {
logger.debug("Bound request context to thread: " + request);
}
try {
ModelAndView mv = null;
try {
processedRequest = checkMultipart(request);
// Determine handler for the current request.
mappedHandler = getHandler(processedRequest, false);
if (mappedHandler == null || mappedHandler.getHandler() == null) {
noHandlerFound(processedRequest, response);
return;
}
// Apply preHandle methods of registered interceptors.
HandlerInterceptor[] interceptors = mappedHandler.getInterceptors();
if (interceptors != null) {
for (int i = 0; i < interceptors.length; i++) {
HandlerInterceptor interceptor = interceptors[i];
if (!interceptor.preHandle(processedRequest, response, mappedHandler.getHandler())) {
triggerAfterCompletion(mappedHandler, interceptorIndex, processedRequest, response, null);
return;
}
interceptorIndex = i;
}
}
// Actually invoke the handler.
HandlerAdapter ha = getHandlerAdapter(mappedHandler.getHandler());
mv = ha.handle(processedRequest, response, mappedHandler.getHandler());
// Apply postHandle methods of registered interceptors.
if (interceptors != null) {
for (int i = interceptors.length - 1; i >= 0; i--) {
HandlerInterceptor interceptor = interceptors[i];
interceptor.postHandle(processedRequest, response, mappedHandler.getHandler(), mv);
}
}
}
catch (ModelAndViewDefiningException ex) {
logger.debug("ModelAndViewDefiningException encountered", ex);
mv = ex.getModelAndView();
}
catch (Exception ex) {
Object handler = (mappedHandler != null ? mappedHandler.getHandler() : null);
mv = processHandlerException(processedRequest, response, handler, ex);
}
// Did the handler return a view to render?
if (mv != null && !mv.wasCleared()) {
render(mv, processedRequest, response);
}
else {
if (logger.isDebugEnabled()) {
logger.debug("Null ModelAndView returned to DispatcherServlet with name '" +
getServletName() + "': assuming HandlerAdapter completed request handling");
}
}
// Trigger after-completion for successful outcome.
triggerAfterCompletion(mappedHandler, interceptorIndex, processedRequest, response, null);
}
catch (Exception ex) {
// Trigger after-completion for thrown exception.
triggerAfterCompletion(mappedHandler, interceptorIndex, processedRequest, response, ex);
throw ex;
}
catch (Error err) {
ServletException ex = new NestedServletException("Handler processing failed", err);
// Trigger after-completion for thrown exception.
triggerAfterCompletion(mappedHandler, interceptorIndex, processedRequest, response, ex);
throw ex;
}
finally {
// Clean up any resources used by a multipart request.
if (processedRequest != request) {
cleanupMultipart(processedRequest);
}
// Reset thread-bound context.
RequestContextHolder.setRequestAttributes(previousRequestAttributes, this.threadContextInheritable);
LocaleContextHolder.setLocaleContext(previousLocaleContext, this.threadContextInheritable);
// Clear request attributes.
requestAttributes.requestCompleted();
if (logger.isDebugEnabled()) {
logger.debug("Cleared thread-bound request context: " + request);
}
}
}
/**
* Override HttpServlet's getLastModified method to evaluate
* the Last-Modified value of the mapped handler.
*/
protected long getLastModified(HttpServletRequest request) {
try {
HandlerExecutionChain mappedHandler = getHandler(request, true);
if (mappedHandler == null || mappedHandler.getHandler() == null) {
// Ignore -> will reappear on doService.
logger.debug("No handler found in getLastModified");
return -1;
}
HandlerAdapter ha = getHandlerAdapter(mappedHandler.getHandler());
long lastModified = ha.getLastModified(request, mappedHandler.getHandler());
if (logger.isDebugEnabled()) {
String requestUri = new UrlPathHelper().getRequestUri(request);
logger.debug("Last-Modified value for [" + requestUri + "] is: " + lastModified);
}
return lastModified;
}
catch (Exception ex) {
// Ignore -> will reappear on doService.
logger.debug("Exception thrown in getLastModified", ex);
return -1;
}
}
/**
* Build a LocaleContext for the given request, exposing the request's
* primary locale as current locale.
*
The default implementation uses the dispatcher's LocaleResolver
* to obtain the current locale, which might change during a request.
* @param request current HTTP request
* @return the corresponding LocaleContext
*/
protected LocaleContext buildLocaleContext(final HttpServletRequest request) {
return new LocaleContext() {
public Locale getLocale() {
return localeResolver.resolveLocale(request);
}
};
}
/**
* Convert the request into a multipart request, and make multipart resolver available.
* If no multipart resolver is set, simply use the existing request.
* @param request current HTTP request
* @return the processed request (multipart wrapper if necessary)
* @see MultipartResolver#resolveMultipart
*/
protected HttpServletRequest checkMultipart(HttpServletRequest request) throws MultipartException {
if (this.multipartResolver != null && this.multipartResolver.isMultipart(request)) {
if (request instanceof MultipartHttpServletRequest) {
logger.debug("Request is already a MultipartHttpServletRequest - if not in a forward, " +
"this typically results from an additional MultipartFilter in web.xml");
}
else {
return this.multipartResolver.resolveMultipart(request);
}
}
// If not returned before: return original request.
return request;
}
/**
* Clean up any resources used by the given multipart request (if any).
* @param request current HTTP request
* @see MultipartResolver#cleanupMultipart
*/
protected void cleanupMultipart(HttpServletRequest request) {
if (request instanceof MultipartHttpServletRequest) {
this.multipartResolver.cleanupMultipart((MultipartHttpServletRequest) request);
}
}
/**
* Return the HandlerExecutionChain for this request.
* Try all handler mappings in order.
* @param request current HTTP request
* @param cache whether to cache the HandlerExecutionChain in a request attribute
* @return the HandlerExceutionChain, or null if no handler could be found
*/
protected HandlerExecutionChain getHandler(HttpServletRequest request, boolean cache) throws Exception {
HandlerExecutionChain handler =
(HandlerExecutionChain) request.getAttribute(HANDLER_EXECUTION_CHAIN_ATTRIBUTE);
if (handler != null) {
if (!cache) {
request.removeAttribute(HANDLER_EXECUTION_CHAIN_ATTRIBUTE);
}
return handler;
}
Iterator it = this.handlerMappings.iterator();
while (it.hasNext()) {
HandlerMapping hm = (HandlerMapping) it.next();
if (logger.isDebugEnabled()) {
logger.debug("Testing handler map [" + hm + "] in DispatcherServlet with name '" +
getServletName() + "'");
}
handler = hm.getHandler(request);
if (handler != null) {
if (cache) {
request.setAttribute(HANDLER_EXECUTION_CHAIN_ATTRIBUTE, handler);
}
return handler;
}
}
return null;
}
/**
* No handler found -> set appropriate HTTP response status.
* @param request current HTTP request
* @param response current HTTP response
* @throws IOException if preparing the response failed
*/
protected void noHandlerFound(HttpServletRequest request, HttpServletResponse response) throws IOException {
if (pageNotFoundLogger.isWarnEnabled()) {
String requestUri = new UrlPathHelper().getRequestUri(request);
pageNotFoundLogger.warn("No mapping for [" + requestUri +
"] in DispatcherServlet with name '" + getServletName() + "'");
}
response.sendError(HttpServletResponse.SC_NOT_FOUND);
}
/**
* Return the HandlerAdapter for this handler object.
* @param handler the handler object to find an adapter for
* @throws ServletException if no HandlerAdapter can be found for the handler.
* This is a fatal error.
*/
protected HandlerAdapter getHandlerAdapter(Object handler) throws ServletException {
Iterator it = this.handlerAdapters.iterator();
while (it.hasNext()) {
HandlerAdapter ha = (HandlerAdapter) it.next();
if (logger.isDebugEnabled()) {
logger.debug("Testing handler adapter [" + ha + "]");
}
if (ha.supports(handler)) {
return ha;
}
}
throw new ServletException("No adapter for handler [" + handler +
"]: Does your handler implement a supported interface like Controller?");
}
/**
* Determine an error ModelAndView via the registered HandlerExceptionResolvers.
* @param request current HTTP request
* @param response current HTTP response
* @param handler the executed handler, or null if none chosen at the time of
* the exception (for example, if multipart resolution failed)
* @param ex the exception that got thrown during handler execution
* @return a corresponding ModelAndView to forward to
* @throws Exception if no error ModelAndView found
*/
protected ModelAndView processHandlerException(
HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
throws Exception {
ModelAndView exMv = null;
for (Iterator it = this.handlerExceptionResolvers.iterator(); exMv == null && it.hasNext();) {
HandlerExceptionResolver resolver = (HandlerExceptionResolver) it.next();
exMv = resolver.resolveException(request, response, handler, ex);
}
if (exMv != null) {
if (logger.isDebugEnabled()) {
logger.debug("Handler execution resulted in exception - forwarding to resolved error view: " + exMv, ex);
}
return exMv;
}
else {
throw ex;
}
}
/**
* Render the given ModelAndView. This is the last stage in handling a request.
* It may involve resolving the view by name.
* @param mv the ModelAndView to render
* @param request current HTTP servlet request
* @param response current HTTP servlet response
* @throws Exception if there's a problem rendering the view
*/
protected void render(ModelAndView mv, HttpServletRequest request, HttpServletResponse response)
throws Exception {
// Determine locale for request and apply it to the response.
Locale locale = this.localeResolver.resolveLocale(request);
response.setLocale(locale);
View view = null;
// Do we need view name translation?
if (!mv.hasView()) {
mv.setViewName(getDefaultViewName(request));
}
if (mv.isReference()) {
// We need to resolve the view name.
view = resolveViewName(mv.getViewName(), mv.getModelInternal(), locale, request);
if (view == null) {
throw new ServletException("Could not resolve view with name '" + mv.getViewName() +
"' in servlet with name '" + getServletName() + "'");
}
}
else {
// No need to lookup: the ModelAndView object contains the actual View object.
view = mv.getView();
if (view == null) {
throw new ServletException("ModelAndView [" + mv + "] neither contains a view name nor a " +
"View object in servlet with name '" + getServletName() + "'");
}
}
// Delegate to the View object for rendering.
if (logger.isDebugEnabled()) {
logger.debug("Rendering view [" + view + "] in DispatcherServlet with name '" + getServletName() + "'");
}
view.render(mv.getModelInternal(), request, response);
}
/**
* Translate the supplied request into a default view name.
* @param request current HTTP servlet request
* @return the view name
* @throws Exception if view name translation failed
*/
protected String getDefaultViewName(HttpServletRequest request) throws Exception {
String viewName = this.viewNameTranslator.getViewName(request);
if (viewName == null) {
throw new ServletException("Could not translate request [" + request +
"] into view name using [" + this.viewNameTranslator.getClass().getName() + "]");
}
return viewName;
}
/**
* Resolve the given view name into a View object (to be rendered).
*
Default implementations asks all ViewResolvers of this dispatcher.
* Can be overridden for custom resolution strategies, potentially based
* on specific model attributes or request parameters.
* @param viewName the name of the view to resolve
* @param model the model to be passed to the view
* @param locale the current locale
* @param request current HTTP servlet request
* @return the View object, or null if none found
* @throws Exception if the view cannot be resolved
* (typically in case of problems creating an actual View object)
* @see ViewResolver#resolveViewName
*/
protected View resolveViewName(String viewName, Map model, Locale locale, HttpServletRequest request)
throws Exception {
for (Iterator it = this.viewResolvers.iterator(); it.hasNext();) {
ViewResolver viewResolver = (ViewResolver) it.next();
View view = viewResolver.resolveViewName(viewName, locale);
if (view != null) {
return view;
}
}
return null;
}
/**
* Trigger afterCompletion callbacks on the mapped HandlerInterceptors.
* Will just invoke afterCompletion for all interceptors whose preHandle
* invocation has successfully completed and returned true.
* @param mappedHandler the mapped HandlerExecutionChain
* @param interceptorIndex index of last interceptor that successfully completed
* @param ex Exception thrown on handler execution, or null if none
* @see HandlerInterceptor#afterCompletion
*/
private void triggerAfterCompletion(
HandlerExecutionChain mappedHandler, int interceptorIndex,
HttpServletRequest request, HttpServletResponse response, Exception ex)
throws Exception {
// Apply afterCompletion methods of registered interceptors.
if (mappedHandler != null) {
HandlerInterceptor[] interceptors = mappedHandler.getInterceptors();
if (interceptors != null) {
for (int i = interceptorIndex; i >= 0; i--) {
HandlerInterceptor interceptor = interceptors[i];
try {
interceptor.afterCompletion(request, response, mappedHandler.getHandler(), ex);
}
catch (Throwable ex2) {
logger.error("HandlerInterceptor.afterCompletion threw exception", ex2);
}
}
}
}
}
/**
* Restore the request attributes after an include.
* @param request current HTTP request
* @param attributesSnapshot the snapshot of the request attributes
* before the include
*/
private void restoreAttributesAfterInclude(HttpServletRequest request, Map attributesSnapshot) {
logger.debug("Restoring snapshot of request attributes after include");
// Need to copy into separate Collection here, to avoid side effects
// on the Enumeration when removing attributes.
Set attrsToCheck = new HashSet();
Enumeration attrNames = request.getAttributeNames();
while (attrNames.hasMoreElements()) {
String attrName = (String) attrNames.nextElement();
if (this.cleanupAfterInclude || attrName.startsWith(DispatcherServlet.class.getName())) {
attrsToCheck.add(attrName);
}
}
// Iterate over the attributes to check, restoring the original value
// or removing the attribute, respectively, if appropriate.
for (Iterator it = attrsToCheck.iterator(); it.hasNext();) {
String attrName = (String) it.next();
Object attrValue = attributesSnapshot.get(attrName);
if (attrValue != null) {
if (logger.isDebugEnabled()) {
logger.debug("Restoring original value of attribute [" + attrName + "] after include");
}
request.setAttribute(attrName, attrValue);
}
else {
if (logger.isDebugEnabled()) {
logger.debug("Removing attribute [" + attrName + "] after include");
}
request.removeAttribute(attrName);
}
}
}
}