/*
* Copyright 2002-2011 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.security.Principal;
import java.util.ArrayList;
import java.util.Collections;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.beans.BeanUtils;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextException;
import org.springframework.context.ApplicationContextInitializer;
import org.springframework.context.ApplicationListener;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.event.ContextRefreshedEvent;
import org.springframework.context.event.SourceFilteringListener;
import org.springframework.context.i18n.LocaleContext;
import org.springframework.context.i18n.LocaleContextHolder;
import org.springframework.context.i18n.SimpleLocaleContext;
import org.springframework.core.annotation.AnnotationAwareOrderComparator;
import org.springframework.util.ClassUtils;
import org.springframework.util.ObjectUtils;
import org.springframework.util.StringUtils;
import org.springframework.web.context.ConfigurableWebApplicationContext;
import org.springframework.web.context.WebApplicationContext;
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.context.support.ServletRequestHandledEvent;
import org.springframework.web.context.support.WebApplicationContextUtils;
import org.springframework.web.context.support.XmlWebApplicationContext;
import org.springframework.web.util.NestedServletException;
import org.springframework.web.util.WebUtils;
/**
* Base servlet for Spring's web framework. Provides integration with
* a Spring application context, in a JavaBean-based overall solution.
*
* <p>This class offers the following functionality:
* <ul>
* <li>Manages a {@link org.springframework.web.context.WebApplicationContext
* WebApplicationContext} instance per servlet. The servlet's configuration is determined
* by beans in the servlet's namespace.
* <li>Publishes events on request processing, whether or not a request is
* successfully handled.
* </ul>
*
* <p>Subclasses must implement {@link #doService} to handle requests. Because this extends
* {@link HttpServletBean} rather than HttpServlet directly, bean properties are
* automatically mapped onto it. Subclasses can override {@link #initFrameworkServlet()}
* for custom initialization.
*
* <p>Detects a "contextClass" parameter at the servlet init-param level,
* falling back to the default context class,
* {@link org.springframework.web.context.support.XmlWebApplicationContext
* XmlWebApplicationContext}, if not found. Note that, with the default
* {@code FrameworkServlet}, a custom context class needs to implement the
* {@link org.springframework.web.context.ConfigurableWebApplicationContext
* ConfigurableWebApplicationContext} SPI.
*
* <p>Accepts an optional "contextInitializerClasses" servlet init-param that
* specifies one or more {@link org.springframework.context.ApplicationContextInitializer
* ApplicationContextInitializer} classes. The managed web application context will be
* delegated to these initializers, allowing for additional programmatic configuration,
* e.g. adding property sources or activating profiles against the {@linkplain
* org.springframework.context.ConfigurableApplicationContext#getEnvironment() context's
* environment}. See also {@link org.springframework.web.context.ContextLoader} which
* supports a "contextInitializerClasses" context-param with identical semantics for
* the "root" web application context.
*
* <p>Passes a "contextConfigLocation" servlet init-param to the context instance,
* parsing it into potentially multiple file paths which can be separated by any
* number of commas and spaces, like "test-servlet.xml, myServlet.xml".
* If not explicitly specified, the context implementation is supposed to build a
* default location from the namespace of the servlet.
*
* <p>Note: In case of multiple config locations, later bean definitions will
* override ones defined in earlier loaded files, at least when using Spring's
* default ApplicationContext implementation. This can be leveraged to
* deliberately override certain bean definitions via an extra XML file.
*
* <p>The default namespace is "'servlet-name'-servlet", e.g. "test-servlet" for a
* servlet-name "test" (leading to a "/WEB-INF/test-servlet.xml" default location
* with XmlWebApplicationContext). The namespace can also be set explicitly via
* the "namespace" servlet init-param.
*
* <p>As of Spring 3.1, {@code FrameworkServlet} may now be injected with a web
* application context, rather than creating its own internally. This is useful in Servlet
* 3.0+ environments, which support programmatic registration of servlet instances. See
* {@link #FrameworkServlet(WebApplicationContext)} Javadoc for details.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @author Sam Brannen
* @author Chris Beams
* @see #doService
* @see #setContextClass
* @see #setContextConfigLocation
* @see #setContextInitializerClasses
* @see #setNamespace
*/
@SuppressWarnings("serial")
public abstract class FrameworkServlet extends HttpServletBean {
/**
* Suffix for WebApplicationContext namespaces. If a servlet of this class is
* given the name "test" in a context, the namespace used by the servlet will
* resolve to "test-servlet".
*/
public static final String DEFAULT_NAMESPACE_SUFFIX = "-servlet";
/**
* Default context class for FrameworkServlet.
* @see org.springframework.web.context.support.XmlWebApplicationContext
*/
public static final Class<?> DEFAULT_CONTEXT_CLASS = XmlWebApplicationContext.class;
/**
* Prefix for the ServletContext attribute for the WebApplicationContext.
* The completion is the servlet name.
*/
public static final String SERVLET_CONTEXT_PREFIX = FrameworkServlet.class.getName() + ".CONTEXT.";
/**
* Any number of these characters are considered delimiters between
* multiple values in a single init-param String value.
*/
private static final String INIT_PARAM_DELIMITERS = ",; \t\n";
/** ServletContext attribute to find the WebApplicationContext in */
private String contextAttribute;
/** WebApplicationContext implementation class to create */
private Class<?> contextClass = DEFAULT_CONTEXT_CLASS;
/** WebApplicationContext id to assign */
private String contextId;
/** Namespace for this servlet */
private String namespace;
/** Explicit context config location */
private String contextConfigLocation;
/** Should we publish the context as a ServletContext attribute? */
private boolean publishContext = true;
/** Should we publish a ServletRequestHandledEvent at the end of each request? */
private boolean publishEvents = true;
/** Expose LocaleContext and RequestAttributes as inheritable for child threads? */
private boolean threadContextInheritable = false;
/** Should we dispatch an HTTP OPTIONS request to {@link #doService}? */
private boolean dispatchOptionsRequest = false;
/** Should we dispatch an HTTP TRACE request to {@link #doService}? */
private boolean dispatchTraceRequest = false;
/** WebApplicationContext for this servlet */
private WebApplicationContext webApplicationContext;
/** Flag used to detect whether onRefresh has already been called */
private boolean refreshEventReceived = false;
/** Comma-delimited ApplicationContextInitializer classnames set through init param */
private String contextInitializerClasses;
/** Actual ApplicationContextInitializer instances to apply to the context */
private ArrayList<ApplicationContextInitializer<ConfigurableApplicationContext>> contextInitializers =
new ArrayList<ApplicationContextInitializer<ConfigurableApplicationContext>>();
/**
* Create a new {@code FrameworkServlet} that will create its own internal web
* application context based on defaults and values provided through servlet
* init-params. Typically used in Servlet 2.5 or earlier environments, where the only
* option for servlet registration is through {@code web.xml} which requires the use
* of a no-arg constructor.
* <p>Calling {@link #setContextConfigLocation} (init-param 'contextConfigLocation')
* will dictate which XML files will be loaded by the
* {@linkplain #DEFAULT_CONTEXT_CLASS default XmlWebApplicationContext}
* <p>Calling {@link #setContextClass} (init-param 'contextClass') overrides the
* default {@code XmlWebApplicationContext} and allows for specifying an alternative class,
* such as {@code AnnotationConfigWebApplicationContext}.
* <p>Calling {@link #setContextInitializerClasses} (init-param 'contextInitializerClasses')
* indicates which {@link ApplicationContextInitializer} classes should be used to
* further configure the internal application context prior to refresh().
* @see #FrameworkServlet(WebApplicationContext)
*/
public FrameworkServlet() {
}
/**
* Create a new {@code FrameworkServlet} with the given web application context. This
* constructor is useful in Servlet 3.0+ environments where instance-based registration
* of servlets is possible through the {@link ServletContext#addServlet} API.
* <p>Using this constructor indicates that the following properties / init-params
* will be ignored:
* <ul>
* <li>{@link #setContextClass(Class)} / 'contextClass'</li>
* <li>{@link #setContextConfigLocation(String)} / 'contextConfigLocation'</li>
* <li>{@link #setContextAttribute(String)} / 'contextAttribute'</li>
* <li>{@link #setNamespace(String)} / 'namespace'</li>
* </ul>
* <p>The given web application context may or may not yet be {@linkplain
* ConfigurableApplicationContext#refresh() refreshed}. If it (a) is an implementation
* of {@link ConfigurableWebApplicationContext} and (b) has <strong>not</strong>
* already been refreshed (the recommended approach), then the following will occur:
* <ul>
* <li>If the given context does not already have a {@linkplain
* ConfigurableApplicationContext#setParent parent}, the root application context
* will be set as the parent.</li>
* <li>If the given context has not already been assigned an {@linkplain
* ConfigurableApplicationContext#setId id}, one will be assigned to it</li>
* <li>{@code ServletContext} and {@code ServletConfig} objects will be delegated to
* the application context</li>
* <li>{@link #postProcessWebApplicationContext} will be called</li>
* <li>Any {@link ApplicationContextInitializer}s specified through the
* "contextInitializerClasses" init-param or through the {@link
* #setContextInitializers} property will be applied.</li>
* <li>{@link ConfigurableApplicationContext#refresh refresh()} will be called</li>
* </ul>
* If the context has already been refreshed or does not implement
* {@code ConfigurableWebApplicationContext}, none of the above will occur under the
* assumption that the user has performed these actions (or not) per his or her
* specific needs.
* <p>See {@link org.springframework.web.WebApplicationInitializer} for usage examples.
* @param webApplicationContext the context to use
* @see #initWebApplicationContext
* @see #configureAndRefreshWebApplicationContext
* @see org.springframework.web.WebApplicationInitializer
*/
public FrameworkServlet(WebApplicationContext webApplicationContext) {
this.webApplicationContext = webApplicationContext;
}
/**
* Set the name of the ServletContext attribute which should be used to retrieve the
* {@link WebApplicationContext} that this servlet is supposed to use.
*/
public void setContextAttribute(String contextAttribute) {
this.contextAttribute = contextAttribute;
}
/**
* Return the name of the ServletContext attribute which should be used to retrieve the
* {@link WebApplicationContext} that this servlet is supposed to use.
*/
public String getContextAttribute() {
return this.contextAttribute;
}
/**
* Set a custom context class. This class must be of type
* {@link org.springframework.web.context.WebApplicationContext}.
* <p>When using the default FrameworkServlet implementation,
* the context class must also implement the
* {@link org.springframework.web.context.ConfigurableWebApplicationContext}
* interface.
* @see #createWebApplicationContext
*/
public void setContextClass(Class<?> contextClass) {
this.contextClass = contextClass;
}
/**
* Return the custom context class.
*/
public Class<?> getContextClass() {
return this.contextClass;
}
/**
* Specify a custom WebApplicationContext id,
* to be used as serialization id for the underlying BeanFactory.
*/
public void setContextId(String contextId) {
this.contextId = contextId;
}
/**
* Return the custom WebApplicationContext id, if any.
*/
public String getContextId() {
return this.contextId;
}
/**
* Set a custom namespace for this servlet,
* to be used for building a default context config location.
*/
public void setNamespace(String namespace) {
this.namespace = namespace;
}
/**
* Return the namespace for this servlet, falling back to default scheme if
* no custom namespace was set: e.g. "test-servlet" for a servlet named "test".
*/
public String getNamespace() {
return (this.namespace != null ? this.namespace : getServletName() + DEFAULT_NAMESPACE_SUFFIX);
}
/**
* Specify the set of fully-qualified {@link ApplicationContextInitializer} class
* names, per the optional "contextInitializerClasses" servlet init-param.
* @see #configureAndRefreshWebApplicationContext(ConfigurableWebApplicationContext)
* @see #applyInitializers(ConfigurableWebApplicationContext)
*/
public void setContextInitializerClasses(String contextInitializerClasses) {
this.contextInitializerClasses = contextInitializerClasses;
}
/**
* Specify which {@link ApplicationContextInitializer} instances should be used
* to initialize the application context used by this {@code FrameworkServlet}.
* @see #configureAndRefreshWebApplicationContext(ConfigurableWebApplicationContext)
* @see #applyInitializers(ConfigurableWebApplicationContext)
*/
public void setContextInitializers(ApplicationContextInitializer<ConfigurableApplicationContext>... contextInitializers) {
for (ApplicationContextInitializer<ConfigurableApplicationContext> initializer : contextInitializers) {
this.contextInitializers.add(initializer);
}
}
/**
* Set the context config location explicitly, instead of relying on the default
* location built from the namespace. This location string can consist of
* multiple locations separated by any number of commas and spaces.
*/
public void setContextConfigLocation(String contextConfigLocation) {
this.contextConfigLocation = contextConfigLocation;
}
/**
* Return the explicit context config location, if any.
*/
public String getContextConfigLocation() {
return this.contextConfigLocation;
}
/**
* Set whether to publish this servlet's context as a ServletContext attribute,
* available to all objects in the web container. Default is "true".
* <p>This is especially handy during testing, although it is debatable whether
* it's good practice to let other application objects access the context this way.
*/
public void setPublishContext(boolean publishContext) {
this.publishContext = publishContext;
}
/**
* Set whether this servlet should publish a ServletRequestHandledEvent at the end
* of each request. Default is "true"; can be turned off for a slight performance
* improvement, provided that no ApplicationListeners rely on such events.
* @see org.springframework.web.context.support.ServletRequestHandledEvent
*/
public void setPublishEvents(boolean publishEvents) {
this.publishEvents = publishEvents;
}
/**
* Set whether to expose the LocaleContext and RequestAttributes as inheritable
* for child threads (using an {@link java.lang.InheritableThreadLocal}).
* <p>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).
* <p><b>WARNING:</b> 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;
}
/**
* Set whether this servlet should dispatch an HTTP OPTIONS request to
* the {@link #doService} method.
* <p>Default is "false", applying {@link javax.servlet.http.HttpServlet}'s
* default behavior (i.e. enumerating all standard HTTP request methods
* as a response to the OPTIONS request).
* <p>Turn this flag on if you prefer OPTIONS requests to go through the
* regular dispatching chain, just like other HTTP requests. This usually
* means that your controllers will receive those requests; make sure
* that those endpoints are actually able to handle an OPTIONS request.
* <p>Note that HttpServlet's default OPTIONS processing will be applied
* in any case if your controllers happen to not set the 'Allow' header
* (as required for an OPTIONS response).
*/
public void setDispatchOptionsRequest(boolean dispatchOptionsRequest) {
this.dispatchOptionsRequest = dispatchOptionsRequest;
}
/**
* Set whether this servlet should dispatch an HTTP TRACE request to
* the {@link #doService} method.
* <p>Default is "false", applying {@link javax.servlet.http.HttpServlet}'s
* default behavior (i.e. reflecting the message received back to the client).
* <p>Turn this flag on if you prefer TRACE requests to go through the
* regular dispatching chain, just like other HTTP requests. This usually
* means that your controllers will receive those requests; make sure
* that those endpoints are actually able to handle a TRACE request.
* <p>Note that HttpServlet's default TRACE processing will be applied
* in any case if your controllers happen to not generate a response
* of content type 'message/http' (as required for a TRACE response).
*/
public void setDispatchTraceRequest(boolean dispatchTraceRequest) {
this.dispatchTraceRequest = dispatchTraceRequest;
}
/**
* Overridden method of {@link HttpServletBean}, invoked after any bean properties
* have been set. Creates this servlet's WebApplicationContext.
*/
@Override
protected final void initServletBean() throws ServletException {
getServletContext().log("Initializing Spring FrameworkServlet '" + getServletName() + "'");
if (this.logger.isInfoEnabled()) {
this.logger.info("FrameworkServlet '" + getServletName() + "': initialization started");
}
long startTime = System.currentTimeMillis();
try {
this.webApplicationContext = initWebApplicationContext();
initFrameworkServlet();
}
catch (ServletException ex) {
this.logger.error("Context initialization failed", ex);
throw ex;
}
catch (RuntimeException ex) {
this.logger.error("Context initialization failed", ex);
throw ex;
}
if (this.logger.isInfoEnabled()) {
long elapsedTime = System.currentTimeMillis() - startTime;
this.logger.info("FrameworkServlet '" + getServletName() + "': initialization completed in " +
elapsedTime + " ms");
}
}
/**
* Initialize and publish the WebApplicationContext for this servlet.
* <p>Delegates to {@link #createWebApplicationContext} for actual creation
* of the context. Can be overridden in subclasses.
* @return the WebApplicationContext instance
* @see #FrameworkServlet(WebApplicationContext)
* @see #setContextClass
* @see #setContextConfigLocation
*/
protected WebApplicationContext initWebApplicationContext() {
WebApplicationContext rootContext =
WebApplicationContextUtils.getWebApplicationContext(getServletContext());
WebApplicationContext wac = null;
if (this.webApplicationContext != null) {
// A context instance was injected at construction time -> use it
wac = this.webApplicationContext;
if (wac instanceof ConfigurableWebApplicationContext) {
ConfigurableWebApplicationContext cwac = (ConfigurableWebApplicationContext) wac;
if (!cwac.isActive()) {
// The context has not yet been refreshed -> provide services such as
// setting the parent context, setting the application context id, etc
if (cwac.getParent() == null) {
// The context instance was injected without an explicit parent -> set
// the root application context (if any; may be null) as the parent
cwac.setParent(rootContext);
}
configureAndRefreshWebApplicationContext(cwac);
}
}
}
if (wac == null) {
// No context instance was injected at construction time -> see if one
// has been registered in the servlet context. If one exists, it is assumed
// that the parent context (if any) has already been set and that the
// user has performed any initialization such as setting the context id
wac = findWebApplicationContext();
}
if (wac == null) {
// No context instance is defined for this servlet -> create a local one
wac = createWebApplicationContext(rootContext);
}
if (!this.refreshEventReceived) {
// Either the context is not a ConfigurableApplicationContext with refresh
// support or the context injected at construction time had already been
// refreshed -> trigger initial onRefresh manually here.
onRefresh(wac);
}
if (this.publishContext) {
// Publish the context as a servlet context attribute.
String attrName = getServletContextAttributeName();
getServletContext().setAttribute(attrName, wac);
if (this.logger.isDebugEnabled()) {
this.logger.debug("Published WebApplicationContext of servlet '" + getServletName() +
"' as ServletContext attribute with name [" + attrName + "]");
}
}
return wac;
}
/**
* Retrieve a <code>WebApplicationContext</code> from the <code>ServletContext</code>
* attribute with the {@link #setContextAttribute configured name}. The
* <code>WebApplicationContext</code> must have already been loaded and stored in the
* <code>ServletContext</code> before this servlet gets initialized (or invoked).
* <p>Subclasses may override this method to provide a different
* <code>WebApplicationContext</code> retrieval strategy.
* @return the WebApplicationContext for this servlet, or <code>null</code> if not found
* @see #getContextAttribute()
*/
protected WebApplicationContext findWebApplicationContext() {
String attrName = getContextAttribute();
if (attrName == null) {
return null;
}
WebApplicationContext wac =
WebApplicationContextUtils.getWebApplicationContext(getServletContext(), attrName);
if (wac == null) {
throw new IllegalStateException("No WebApplicationContext found: initializer not registered?");
}
return wac;
}
/**
* Instantiate the WebApplicationContext for this servlet, either a default
* {@link org.springframework.web.context.support.XmlWebApplicationContext}
* or a {@link #setContextClass custom context class}, if set.
* <p>This implementation expects custom contexts to implement the
* {@link org.springframework.web.context.ConfigurableWebApplicationContext}
* interface. Can be overridden in subclasses.
* <p>Do not forget to register this servlet instance as application listener on the
* created context (for triggering its {@link #onRefresh callback}, and to call
* {@link org.springframework.context.ConfigurableApplicationContext#refresh()}
* before returning the context instance.
* @param parent the parent ApplicationContext to use, or <code>null</code> if none
* @return the WebApplicationContext for this servlet
* @see org.springframework.web.context.support.XmlWebApplicationContext
*/
protected WebApplicationContext createWebApplicationContext(ApplicationContext parent) {
Class<?> contextClass = getContextClass();
if (this.logger.isDebugEnabled()) {
this.logger.debug("Servlet with name '" + getServletName() +
"' will try to create custom WebApplicationContext context of class '" +
contextClass.getName() + "'" + ", using parent context [" + parent + "]");
}
if (!ConfigurableWebApplicationContext.class.isAssignableFrom(contextClass)) {
throw new ApplicationContextException(
"Fatal initialization error in servlet with name '" + getServletName() +
"': custom WebApplicationContext class [" + contextClass.getName() +
"] is not of type ConfigurableWebApplicationContext");
}
ConfigurableWebApplicationContext wac =
(ConfigurableWebApplicationContext) BeanUtils.instantiateClass(contextClass);
wac.setParent(parent);
wac.setConfigLocation(getContextConfigLocation());
configureAndRefreshWebApplicationContext(wac);
return wac;
}
protected void configureAndRefreshWebApplicationContext(ConfigurableWebApplicationContext wac) {
if (ObjectUtils.identityToString(wac).equals(wac.getId())) {
// The application context id is still set to its original default value
// -> assign a more useful id based on available information
if (this.contextId != null) {
wac.setId(this.contextId);
}
else {
// Generate default id...
ServletContext sc = getServletContext();
if (sc.getMajorVersion() == 2 && sc.getMinorVersion() < 5) {
// Servlet <= 2.4: resort to name specified in web.xml, if any.
String servletContextName = sc.getServletContextName();
if (servletContextName != null) {
wac.setId(ConfigurableWebApplicationContext.APPLICATION_CONTEXT_ID_PREFIX + servletContextName +
"." + getServletName());
}
else {
wac.setId(ConfigurableWebApplicationContext.APPLICATION_CONTEXT_ID_PREFIX + getServletName());
}
}
else {
// Servlet 2.5's getContextPath available!
wac.setId(ConfigurableWebApplicationContext.APPLICATION_CONTEXT_ID_PREFIX +
ObjectUtils.getDisplayString(sc.getContextPath()) + "/" + getServletName());
}
}
}
wac.setServletContext(getServletContext());
wac.setServletConfig(getServletConfig());
wac.setNamespace(getNamespace());
wac.addApplicationListener(new SourceFilteringListener(wac, new ContextRefreshListener()));
postProcessWebApplicationContext(wac);
applyInitializers(wac);
wac.refresh();
}
/**
* Instantiate the WebApplicationContext for this servlet, either a default
* {@link org.springframework.web.context.support.XmlWebApplicationContext}
* or a {@link #setContextClass custom context class}, if set.
* Delegates to #createWebApplicationContext(ApplicationContext).
* @param parent the parent WebApplicationContext to use, or <code>null</code> if none
* @return the WebApplicationContext for this servlet
* @see org.springframework.web.context.support.XmlWebApplicationContext
* @see #createWebApplicationContext(ApplicationContext)
*/
protected WebApplicationContext createWebApplicationContext(WebApplicationContext parent) {
return createWebApplicationContext((ApplicationContext) parent);
}
/**
* Delegate the WebApplicationContext before it is refreshed to any
* {@link ApplicationContextInitializer} instances specified by the
* "contextInitializerClasses" servlet init-param.
* <p>See also {@link #postProcessWebApplicationContext}, which is designed to allow
* subclasses (as opposed to end-users) to modify the application context, and is
* called immediately after this method.
* @param wac the configured WebApplicationContext (not refreshed yet)
* @see #createWebApplicationContext
* @see #postProcessWebApplicationContext
* @see ConfigurableApplicationContext#refresh()
*/
@SuppressWarnings("unchecked")
protected void applyInitializers(ConfigurableApplicationContext wac) {
if (this.contextInitializerClasses != null) {
String[] initializerClassNames =
StringUtils.tokenizeToStringArray(this.contextInitializerClasses, INIT_PARAM_DELIMITERS);
for (String initializerClassName : initializerClassNames) {
ApplicationContextInitializer<ConfigurableApplicationContext> initializer;
try {
Class<?> initializerClass = ClassUtils.forName(initializerClassName, wac.getClassLoader());
initializer = BeanUtils.instantiateClass(initializerClass, ApplicationContextInitializer.class);
}
catch (Exception ex) {
throw new IllegalArgumentException(
String.format("Could not instantiate class [%s] specified via " +
"'contextInitializerClasses' init-param", initializerClassName), ex);
}
this.contextInitializers.add(initializer);
}
}
Collections.sort(this.contextInitializers, new AnnotationAwareOrderComparator());
for (ApplicationContextInitializer<ConfigurableApplicationContext> initializer : this.contextInitializers) {
initializer.initialize(wac);
}
}
/**
* Post-process the given WebApplicationContext before it is refreshed
* and activated as context for this servlet.
* <p>The default implementation is empty. <code>refresh()</code> will
* be called automatically after this method returns.
* <p>Note that this method is designed to allow subclasses to modify the application
* context, while {@link #initializeWebApplicationContext} is designed to allow
* end-users to modify the context through the use of
* {@link ApplicationContextInitializer}s.
* @param wac the configured WebApplicationContext (not refreshed yet)
* @see #createWebApplicationContext
* @see #initializeWebApplicationContext
* @see ConfigurableWebApplicationContext#refresh()
*/
protected void postProcessWebApplicationContext(ConfigurableWebApplicationContext wac) {
}
/**
* Return the ServletContext attribute name for this servlet's WebApplicationContext.
* <p>The default implementation returns
* <code>SERVLET_CONTEXT_PREFIX + servlet name</code>.
* @see #SERVLET_CONTEXT_PREFIX
* @see #getServletName
*/
public String getServletContextAttributeName() {
return SERVLET_CONTEXT_PREFIX + getServletName();
}
/**
* Return this servlet's WebApplicationContext.
*/
public final WebApplicationContext getWebApplicationContext() {
return this.webApplicationContext;
}
/**
* This method will be invoked after any bean properties have been set and
* the WebApplicationContext has been loaded. The default implementation is empty;
* subclasses may override this method to perform any initialization they require.
* @throws ServletException in case of an initialization exception
*/
protected void initFrameworkServlet() throws ServletException {
}
/**
* Refresh this servlet's application context, as well as the
* dependent state of the servlet.
* @see #getWebApplicationContext()
* @see org.springframework.context.ConfigurableApplicationContext#refresh()
*/
public void refresh() {
WebApplicationContext wac = getWebApplicationContext();
if (!(wac instanceof ConfigurableApplicationContext)) {
throw new IllegalStateException("WebApplicationContext does not support refresh: " + wac);
}
((ConfigurableApplicationContext) wac).refresh();
}
/**
* Callback that receives refresh events from this servlet's WebApplicationContext.
* <p>The default implementation calls {@link #onRefresh},
* triggering a refresh of this servlet's context-dependent state.
* @param event the incoming ApplicationContext event
*/
public void onApplicationEvent(ContextRefreshedEvent event) {
this.refreshEventReceived = true;
onRefresh(event.getApplicationContext());
}
/**
* Template method which can be overridden to add servlet-specific refresh work.
* Called after successful context refresh.
* <p>This implementation is empty.
* @param context the current WebApplicationContext
* @see #refresh()
*/
protected void onRefresh(ApplicationContext context) {
// For subclasses: do nothing by default.
}
/**
* Delegate GET requests to processRequest/doService.
* <p>Will also be invoked by HttpServlet's default implementation of <code>doHead</code>,
* with a <code>NoBodyResponse</code> that just captures the content length.
* @see #doService
* @see #doHead
*/
@Override
protected final void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
/**
* Delegate POST requests to {@link #processRequest}.
* @see #doService
*/
@Override
protected final void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
/**
* Delegate PUT requests to {@link #processRequest}.
* @see #doService
*/
@Override
protected final void doPut(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
/**
* Delegate DELETE requests to {@link #processRequest}.
* @see #doService
*/
@Override
protected final void doDelete(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
/**
* Delegate OPTIONS requests to {@link #processRequest}, if desired.
* <p>Applies HttpServlet's standard OPTIONS processing otherwise,
* and also if there is still no 'Allow' header set after dispatching.
* @see #doService
*/
@Override
protected void doOptions(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
if (this.dispatchOptionsRequest) {
processRequest(request, response);
if (response.containsHeader("Allow")) {
// Proper OPTIONS response coming from a handler - we're done.
return;
}
}
super.doOptions(request, response);
}
/**
* Delegate TRACE requests to {@link #processRequest}, if desired.
* <p>Applies HttpServlet's standard TRACE processing otherwise.
* @see #doService
*/
@Override
protected void doTrace(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
if (this.dispatchTraceRequest) {
processRequest(request, response);
if ("message/http".equals(response.getContentType())) {
// Proper TRACE response coming from a handler - we're done.
return;
}
}
super.doTrace(request, response);
}
/**
* Process this request, publishing an event regardless of the outcome.
* <p>The actual event handling is performed by the abstract
* {@link #doService} template method.
*/
protected final void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
long startTime = System.currentTimeMillis();
Throwable failureCause = null;
// 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 = null;
if (previousRequestAttributes == null || previousRequestAttributes.getClass().equals(ServletRequestAttributes.class)) {
requestAttributes = new ServletRequestAttributes(request);
RequestContextHolder.setRequestAttributes(requestAttributes, this.threadContextInheritable);
}
if (logger.isTraceEnabled()) {
logger.trace("Bound request context to thread: " + request);
}
try {
doService(request, response);
}
catch (ServletException ex) {
failureCause = ex;
throw ex;
}
catch (IOException ex) {
failureCause = ex;
throw ex;
}
catch (Throwable ex) {
failureCause = ex;
throw new NestedServletException("Request processing failed", ex);
}
finally {
// Clear request attributes and reset thread-bound context.
LocaleContextHolder.setLocaleContext(previousLocaleContext, this.threadContextInheritable);
if (requestAttributes != null) {
RequestContextHolder.setRequestAttributes(previousRequestAttributes, this.threadContextInheritable);
requestAttributes.requestCompleted();
}
if (logger.isTraceEnabled()) {
logger.trace("Cleared thread-bound request context: " + request);
}
if (logger.isDebugEnabled()) {
if (failureCause != null) {
this.logger.debug("Could not complete request", failureCause);
}
else {
this.logger.debug("Successfully completed request");
}
}
if (this.publishEvents) {
// Whether or not we succeeded, publish an event.
long processingTime = System.currentTimeMillis() - startTime;
this.webApplicationContext.publishEvent(
new ServletRequestHandledEvent(this,
request.getRequestURI(), request.getRemoteAddr(),
request.getMethod(), getServletConfig().getServletName(),
WebUtils.getSessionId(request), getUsernameForRequest(request),
processingTime, failureCause));
}
}
}
/**
* Build a LocaleContext for the given request, exposing the request's
* primary locale as current locale.
* @param request current HTTP request
* @return the corresponding LocaleContext
*/
protected LocaleContext buildLocaleContext(HttpServletRequest request) {
return new SimpleLocaleContext(request.getLocale());
}
/**
* Determine the username for the given request.
* <p>The default implementation takes the name of the UserPrincipal, if any.
* Can be overridden in subclasses.
* @param request current HTTP request
* @return the username, or <code>null</code> if none found
* @see javax.servlet.http.HttpServletRequest#getUserPrincipal()
*/
protected String getUsernameForRequest(HttpServletRequest request) {
Principal userPrincipal = request.getUserPrincipal();
return (userPrincipal != null ? userPrincipal.getName() : null);
}
/**
* Subclasses must implement this method to do the work of request handling,
* receiving a centralized callback for GET, POST, PUT and DELETE.
* <p>The contract is essentially the same as that for the commonly overridden
* <code>doGet</code> or <code>doPost</code> methods of HttpServlet.
* <p>This class intercepts calls to ensure that exception handling and
* event publication takes place.
* @param request current HTTP request
* @param response current HTTP response
* @throws Exception in case of any kind of processing failure
* @see javax.servlet.http.HttpServlet#doGet
* @see javax.servlet.http.HttpServlet#doPost
*/
protected abstract void doService(HttpServletRequest request, HttpServletResponse response)
throws Exception;
/**
* Close the WebApplicationContext of this servlet.
* @see org.springframework.context.ConfigurableApplicationContext#close()
*/
@Override
public void destroy() {
getServletContext().log("Destroying Spring FrameworkServlet '" + getServletName() + "'");
if (this.webApplicationContext instanceof ConfigurableApplicationContext) {
((ConfigurableApplicationContext) this.webApplicationContext).close();
}
}
/**
* ApplicationListener endpoint that receives events from this servlet's WebApplicationContext
* only, delegating to <code>onApplicationEvent</code> on the FrameworkServlet instance.
*/
private class ContextRefreshListener implements ApplicationListener<ContextRefreshedEvent> {
public void onApplicationEvent(ContextRefreshedEvent event) {
FrameworkServlet.this.onApplicationEvent(event);
}
}
}