https://github.com/spring-projects/spring-framework: Spring Web MVC (Spring IO)
  • Juergen Hoeller 
/*
 * 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
 *
 *      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.Collection;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.stream.Collectors;
import javax.servlet.DispatcherType;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;

import org.springframework.beans.BeanUtils;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
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.GenericTypeResolver;
import org.springframework.core.annotation.AnnotationAwareOrderComparator;
import org.springframework.core.env.ConfigurableEnvironment;
import org.springframework.http.HttpMethod;
import org.springframework.http.HttpStatus;
import org.springframework.lang.Nullable;
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.ConfigurableWebEnvironment;
import org.springframework.web.context.ContextLoader;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.request.NativeWebRequest;
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.request.async.CallableProcessingInterceptor;
import org.springframework.web.context.request.async.WebAsyncManager;
import org.springframework.web.context.request.async.WebAsyncUtils;
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.cors.CorsUtils;
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.

This class offers the following functionality:

    

  • Manages a 
WebApplicationContext instance per servlet. The servlet's configuration is determined by beans in the servlet's namespace. 
  • Publishes events on request processing, whether or not a request is
successfully handled.



Subclasses must implement doService to handle requests. Because this extends HttpServletBean rather than HttpServlet directly, bean properties are automatically mapped onto it. Subclasses can override initFrameworkServlet() for custom initialization. 
Detects a "contextClass" parameter at the servlet init-param level, falling back to the default context class, 
XmlWebApplicationContext, if not found. Note that, with the default FrameworkServlet, a custom context class needs to implement the 
ConfigurableWebApplicationContext SPI. 
Accepts an optional "contextInitializerClasses" servlet init-param that specifies one or more 
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 context's
environment. See also ContextLoader which supports a "contextInitializerClasses" context-param with identical semantics for the "root" web application context. 
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.

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.

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.

As of Spring 3.1, 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 FrameworkServlet(WebApplicationContext) Javadoc for details. 
Author:Rod Johnson, Juergen Hoeller, Sam Brannen, Chris Beams, Rossen Stoyanchev, Phillip Webb
See Also:
/**
 * 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
 * @author Rossen Stoyanchev
 * @author Phillip Webb
 * @see #doService
 * @see #setContextClass
 * @see #setContextConfigLocation
 * @see #setContextInitializerClasses
 * @see #setNamespace
 */
@SuppressWarnings("serial")
public abstract class FrameworkServlet extends HttpServletBean implements ApplicationContextAware {

	
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".

/**
	 * 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 Also:
  • XmlWebApplicationContext
/**
	 * 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.

/**
	 * 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.

/**
	 * 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. 
/** ServletContext attribute to find the WebApplicationContext in. */
	@Nullable
	private String contextAttribute;

	
WebApplicationContext implementation class to create. 
/** WebApplicationContext implementation class to create. */
	private Class<?> contextClass = DEFAULT_CONTEXT_CLASS;

	
WebApplicationContext id to assign. 
/** WebApplicationContext id to assign. */
	@Nullable
	private String contextId;

	
Namespace for this servlet. 
/** Namespace for this servlet. */
	@Nullable
	private String namespace;

	
Explicit context config location. 
/** Explicit context config location. */
	@Nullable
	private String contextConfigLocation;

	
Actual ApplicationContextInitializer instances to apply to the context. 
/** Actual ApplicationContextInitializer instances to apply to the context. */
	private final List<ApplicationContextInitializer<ConfigurableApplicationContext>> contextInitializers =
			new ArrayList<>();

	
Comma-delimited ApplicationContextInitializer class names set through init param. 
/** Comma-delimited ApplicationContextInitializer class names set through init param. */
	@Nullable
	private String contextInitializerClasses;

	
Should we publish the context as a ServletContext attribute?. 
/** Should we publish the context as a ServletContext attribute?. */
	private boolean publishContext = true;

	
Should we publish a ServletRequestHandledEvent at the end of each request?. 
/** Should we publish a ServletRequestHandledEvent at the end of each request?. */
	private boolean publishEvents = true;

	
Expose LocaleContext and RequestAttributes as inheritable for child threads?. 
/** Expose LocaleContext and RequestAttributes as inheritable for child threads?. */
	private boolean threadContextInheritable = false;

	
Should we dispatch an HTTP OPTIONS request to doService?. 
/** Should we dispatch an HTTP OPTIONS request to {@link #doService}?. */
	private boolean dispatchOptionsRequest = false;

	
Should we dispatch an HTTP TRACE request to doService?. 
/** Should we dispatch an HTTP TRACE request to {@link #doService}?. */
	private boolean dispatchTraceRequest = false;

	
Whether to log potentially sensitive info (request params at DEBUG + headers at TRACE). 
/** Whether to log potentially sensitive info (request params at DEBUG + headers at TRACE). */
	private boolean enableLoggingRequestDetails = false;

	
WebApplicationContext for this servlet. 
/** WebApplicationContext for this servlet. */
	@Nullable
	private WebApplicationContext webApplicationContext;

	
If the WebApplicationContext was injected via setApplicationContext. 
/** If the WebApplicationContext was injected via {@link #setApplicationContext}. */
	private boolean webApplicationContextInjected = false;

	
Flag used to detect whether onRefresh has already been called. 
/** Flag used to detect whether onRefresh has already been called. */
	private volatile boolean refreshEventReceived = false;

	
Monitor for synchronized onRefresh execution. 
/** Monitor for synchronized onRefresh execution. */
	private final Object onRefreshMonitor = new Object();


	
Create a new 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 web.xml which requires the use of a no-arg constructor. 
Calling setContextConfigLocation (init-param 'contextConfigLocation') will dictate which XML files will be loaded by the default XmlWebApplicationContext 
Calling setContextClass (init-param 'contextClass') overrides the default XmlWebApplicationContext and allows for specifying an alternative class, such as AnnotationConfigWebApplicationContext. 
Calling setContextInitializerClasses (init-param 'contextInitializerClasses') indicates which ApplicationContextInitializer classes should be used to further configure the internal application context prior to refresh(). 
See Also:
/**
	 * 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 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 ServletContext.addServlet API. 
Using this constructor indicates that the following properties / init-params
will be ignored:



The given web application context may or may not yet be refreshed. If it (a) is an implementation of ConfigurableWebApplicationContext and (b) has not
already been refreshed (the recommended approach), then the following will occur:

    

  • If the given context does not already have a parent, the root application context will be set as the parent.
    • 

  • If the given context has not already been assigned an id, one will be assigned to it
    • 

  • ServletContext and ServletConfig objects will be delegated to the application context
    • 

  • postProcessWebApplicationContext will be called
    • 

  • Any ApplicationContextInitializers specified through the "contextInitializerClasses" init-param or through the setContextInitializers property will be applied.
    • 

  • refresh() will be called
    • 

 If the context has already been refreshed or does not implement 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. 
See WebApplicationInitializer for usage examples. 
Params:
  • webApplicationContext – the context to use
See Also:
/**
	 * 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 ApplicationContextInitializers} 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 WebApplicationContext that this servlet is supposed to use. 
/**
	 * 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(@Nullable String contextAttribute) {
		this.contextAttribute = contextAttribute;
	}

	
Return the name of the ServletContext attribute which should be used to retrieve the WebApplicationContext that this servlet is supposed to use. 
/**
	 * Return the name of the ServletContext attribute which should be used to retrieve the
	 * {@link WebApplicationContext} that this servlet is supposed to use.
	 */
	@Nullable
	public String getContextAttribute() {
		return this.contextAttribute;
	}

	
Set a custom context class. This class must be of type WebApplicationContext. 
When using the default FrameworkServlet implementation, the context class must also implement the ConfigurableWebApplicationContext interface. 
See Also:
/**
	 * 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.

/**
	 * 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.

/**
	 * Specify a custom WebApplicationContext id,
	 * to be used as serialization id for the underlying BeanFactory.
	 */
	public void setContextId(@Nullable String contextId) {
		this.contextId = contextId;
	}

	
Return the custom WebApplicationContext id, if any.

/**
	 * Return the custom WebApplicationContext id, if any.
	 */
	@Nullable
	public String getContextId() {
		return this.contextId;
	}

	
Set a custom namespace for this servlet,
to be used for building a default context config location.

/**
	 * 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".

/**
	 * 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);
	}

	
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.

/**
	 * 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(@Nullable String contextConfigLocation) {
		this.contextConfigLocation = contextConfigLocation;
	}

	
Return the explicit context config location, if any.

/**
	 * Return the explicit context config location, if any.
	 */
	@Nullable
	public String getContextConfigLocation() {
		return this.contextConfigLocation;
	}

	
Specify which ApplicationContextInitializer instances should be used to initialize the application context used by this FrameworkServlet. 
See Also:
/**
	 * Specify which {@link ApplicationContextInitializer} instances should be used
	 * to initialize the application context used by this {@code FrameworkServlet}.
	 * @see #configureAndRefreshWebApplicationContext
	 * @see #applyInitializers
	 */
	@SuppressWarnings("unchecked")
	public void setContextInitializers(@Nullable ApplicationContextInitializer<?>... initializers) {
		if (initializers != null) {
			for (ApplicationContextInitializer<?> initializer : initializers) {
				this.contextInitializers.add((ApplicationContextInitializer<ConfigurableApplicationContext>) initializer);
			}
		}
	}

	
Specify the set of fully-qualified ApplicationContextInitializer class names, per the optional "contextInitializerClasses" servlet init-param. 
See Also:
/**
	 * Specify the set of fully-qualified {@link ApplicationContextInitializer} class
	 * names, per the optional "contextInitializerClasses" servlet init-param.
	 * @see #configureAndRefreshWebApplicationContext(ConfigurableWebApplicationContext)
	 * @see #applyInitializers(ConfigurableApplicationContext)
	 */
	public void setContextInitializerClasses(String contextInitializerClasses) {
		this.contextInitializerClasses = contextInitializerClasses;
	}

	
Set whether to publish this servlet's context as a ServletContext attribute,
available to all objects in the web container. Default is "true".

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.

/**
	 * 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 Also:
  • ServletRequestHandledEvent
/**
	 * 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 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 ThreadPoolExecutor), since this will expose the inherited context to such a pooled thread. 
/**
	 * 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 doService method. 
Default in the FrameworkServlet is "false", applying HttpServlet's default behavior (i.e.enumerating all standard HTTP request methods as a response to the OPTIONS request). Note however that as of 4.3 the DispatcherServlet sets this property to "true" by default due to its built-in support for OPTIONS. 
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.

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).

/**
	 * Set whether this servlet should dispatch an HTTP OPTIONS request to
	 * the {@link #doService} method.
	 * <p>Default in the {@code FrameworkServlet} 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).
	 * Note however that as of 4.3 the {@code DispatcherServlet} sets this
	 * property to "true" by default due to its built-in support for OPTIONS.
	 * <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 doService method. 
Default is "false", applying HttpServlet's default behavior (i.e. reflecting the message received back to the client). 
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.

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).

/**
	 * 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;
	}

	
Whether to log request params at DEBUG level, and headers at TRACE level.
Both may contain sensitive information.

By default set to false so that request details are not shown. 
Params:
  • enable – whether to enable or not
Since:5.1
/**
	 * Whether to log request params at DEBUG level, and headers at TRACE level.
	 * Both may contain sensitive information.
	 * <p>By default set to {@code false} so that request details are not shown.
	 * @param enable whether to enable or not
	 * @since 5.1
	 */
	public void setEnableLoggingRequestDetails(boolean enable) {
		this.enableLoggingRequestDetails = enable;
	}

	
Whether logging of potentially sensitive, request details at DEBUG and
TRACE level is allowed.

Since:5.1
/**
	 * Whether logging of potentially sensitive, request details at DEBUG and
	 * TRACE level is allowed.
	 * @since 5.1
	 */
	public boolean isEnableLoggingRequestDetails() {
		return this.enableLoggingRequestDetails;
	}

	
Called by Spring via ApplicationContextAware to inject the current application context. This method allows FrameworkServlets to be registered as Spring beans inside an existing WebApplicationContext rather than finding a bootstrapped context. 
Primarily added to support use in embedded servlet containers.

Since:4.0
/**
	 * Called by Spring via {@link ApplicationContextAware} to inject the current
	 * application context. This method allows FrameworkServlets to be registered as
	 * Spring beans inside an existing {@link WebApplicationContext} rather than
	 * {@link #findWebApplicationContext() finding} a
	 * {@link org.springframework.web.context.ContextLoaderListener bootstrapped} context.
	 * <p>Primarily added to support use in embedded servlet containers.
	 * @since 4.0
	 */
	@Override
	public void setApplicationContext(ApplicationContext applicationContext) {
		if (this.webApplicationContext == null && applicationContext instanceof WebApplicationContext) {
			this.webApplicationContext = (WebApplicationContext) applicationContext;
			this.webApplicationContextInjected = true;
		}
	}


	
Overridden method of HttpServletBean, invoked after any bean properties have been set. Creates this servlet's WebApplicationContext. 
/**
	 * 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 " + getClass().getSimpleName() + " '" + getServletName() + "'");
		if (logger.isInfoEnabled()) {
			logger.info("Initializing Servlet '" + getServletName() + "'");
		}
		long startTime = System.currentTimeMillis();

		try {
			this.webApplicationContext = initWebApplicationContext();
			initFrameworkServlet();
		}
		catch (ServletException | RuntimeException ex) {
			logger.error("Context initialization failed", ex);
			throw ex;
		}

		if (logger.isDebugEnabled()) {
			String value = this.enableLoggingRequestDetails ?
					"shown which may lead to unsafe logging of potentially sensitive data" :
					"masked to prevent unsafe logging of potentially sensitive data";
			logger.debug("enableLoggingRequestDetails='" + this.enableLoggingRequestDetails +
					"': request parameters and headers will be " + value);
		}

		if (logger.isInfoEnabled()) {
			logger.info("Completed initialization in " + (System.currentTimeMillis() - startTime) + " ms");
		}
	}

	
Initialize and publish the WebApplicationContext for this servlet.

Delegates to createWebApplicationContext for actual creation of the context. Can be overridden in subclasses. 
See Also:
Returns:the WebApplicationContext instance
/**
	 * 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.
			synchronized (this.onRefreshMonitor) {
				onRefresh(wac);
			}
		}

		if (this.publishContext) {
			// Publish the context as a servlet context attribute.
			String attrName = getServletContextAttributeName();
			getServletContext().setAttribute(attrName, wac);
		}

		return wac;
	}

	
Retrieve a WebApplicationContext from the ServletContext attribute with the configured name. The WebApplicationContext must have already been loaded and stored in the ServletContext before this servlet gets initialized (or invoked). 
Subclasses may override this method to provide a different WebApplicationContext retrieval strategy. 
See Also:
Returns:the WebApplicationContext for this servlet, or null if not found
/**
	 * Retrieve a {@code WebApplicationContext} from the {@code ServletContext}
	 * attribute with the {@link #setContextAttribute configured name}. The
	 * {@code WebApplicationContext} must have already been loaded and stored in the
	 * {@code ServletContext} before this servlet gets initialized (or invoked).
	 * <p>Subclasses may override this method to provide a different
	 * {@code WebApplicationContext} retrieval strategy.
	 * @return the WebApplicationContext for this servlet, or {@code null} if not found
	 * @see #getContextAttribute()
	 */
	@Nullable
	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 XmlWebApplicationContext or a custom context class, if set. 
This implementation expects custom contexts to implement the ConfigurableWebApplicationContext interface. Can be overridden in subclasses. 
Do not forget to register this servlet instance as application listener on the created context (for triggering its callback, and to call ConfigurableApplicationContext.refresh() before returning the context instance. 
Params:
  • parent – the parent ApplicationContext to use, or null if none
See Also:
Returns:the WebApplicationContext for this servlet
/**
	 * 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} if none
	 * @return the WebApplicationContext for this servlet
	 * @see org.springframework.web.context.support.XmlWebApplicationContext
	 */
	protected WebApplicationContext createWebApplicationContext(@Nullable ApplicationContext parent) {
		Class<?> contextClass = getContextClass();
		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.setEnvironment(getEnvironment());
		wac.setParent(parent);
		String configLocation = getContextConfigLocation();
		if (configLocation != null) {
			wac.setConfigLocation(configLocation);
		}
		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...
				wac.setId(ConfigurableWebApplicationContext.APPLICATION_CONTEXT_ID_PREFIX +
						ObjectUtils.getDisplayString(getServletContext().getContextPath()) + '/' + getServletName());
			}
		}

		wac.setServletContext(getServletContext());
		wac.setServletConfig(getServletConfig());
		wac.setNamespace(getNamespace());
		wac.addApplicationListener(new SourceFilteringListener(wac, new ContextRefreshListener()));

		// The wac environment's #initPropertySources will be called in any case when the context
		// is refreshed; do it eagerly here to ensure servlet property sources are in place for
		// use in any post-processing or initialization that occurs below prior to #refresh
		ConfigurableEnvironment env = wac.getEnvironment();
		if (env instanceof ConfigurableWebEnvironment) {
			((ConfigurableWebEnvironment) env).initPropertySources(getServletContext(), getServletConfig());
		}

		postProcessWebApplicationContext(wac);
		applyInitializers(wac);
		wac.refresh();
	}

	
Instantiate the WebApplicationContext for this servlet, either a default XmlWebApplicationContext or a custom context class, if set. Delegates to #createWebApplicationContext(ApplicationContext). 
Params:
  • parent – the parent WebApplicationContext to use, or null if none
See Also:
Returns:the WebApplicationContext for this servlet
/**
	 * 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} if none
	 * @return the WebApplicationContext for this servlet
	 * @see org.springframework.web.context.support.XmlWebApplicationContext
	 * @see #createWebApplicationContext(ApplicationContext)
	 */
	protected WebApplicationContext createWebApplicationContext(@Nullable WebApplicationContext parent) {
		return createWebApplicationContext((ApplicationContext) parent);
	}

	
Post-process the given WebApplicationContext before it is refreshed
and activated as context for this servlet.

The default implementation is empty. refresh() will be called automatically after this method returns. 
Note that this method is designed to allow subclasses to modify the application context, while initWebApplicationContext is designed to allow end-users to modify the context through the use of ApplicationContextInitializers. 
Params:
  • wac – the configured WebApplicationContext (not refreshed yet)
See Also:
/**
	 * Post-process the given WebApplicationContext before it is refreshed
	 * and activated as context for this servlet.
	 * <p>The default implementation is empty. {@code refresh()} 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 #initWebApplicationContext} is designed to allow
	 * end-users to modify the context through the use of
	 * {@link ApplicationContextInitializer ApplicationContextInitializers}.
	 * @param wac the configured WebApplicationContext (not refreshed yet)
	 * @see #createWebApplicationContext
	 * @see #initWebApplicationContext
	 * @see ConfigurableWebApplicationContext#refresh()
	 */
	protected void postProcessWebApplicationContext(ConfigurableWebApplicationContext wac) {
	}

	
Delegate the WebApplicationContext before it is refreshed to any ApplicationContextInitializer instances specified by the "contextInitializerClasses" servlet init-param. 
See also postProcessWebApplicationContext, which is designed to allow subclasses (as opposed to end-users) to modify the application context, and is called immediately before this method. 
Params:
  • wac – the configured WebApplicationContext (not refreshed yet)
See Also:
/**
	 * 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 before this method.
	 * @param wac the configured WebApplicationContext (not refreshed yet)
	 * @see #createWebApplicationContext
	 * @see #postProcessWebApplicationContext
	 * @see ConfigurableApplicationContext#refresh()
	 */
	protected void applyInitializers(ConfigurableApplicationContext wac) {
		String globalClassNames = getServletContext().getInitParameter(ContextLoader.GLOBAL_INITIALIZER_CLASSES_PARAM);
		if (globalClassNames != null) {
			for (String className : StringUtils.tokenizeToStringArray(globalClassNames, INIT_PARAM_DELIMITERS)) {
				this.contextInitializers.add(loadInitializer(className, wac));
			}
		}

		if (this.contextInitializerClasses != null) {
			for (String className : StringUtils.tokenizeToStringArray(this.contextInitializerClasses, INIT_PARAM_DELIMITERS)) {
				this.contextInitializers.add(loadInitializer(className, wac));
			}
		}

		AnnotationAwareOrderComparator.sort(this.contextInitializers);
		for (ApplicationContextInitializer<ConfigurableApplicationContext> initializer : this.contextInitializers) {
			initializer.initialize(wac);
		}
	}

	@SuppressWarnings("unchecked")
	private ApplicationContextInitializer<ConfigurableApplicationContext> loadInitializer(
			String className, ConfigurableApplicationContext wac) {
		try {
			Class<?> initializerClass = ClassUtils.forName(className, wac.getClassLoader());
			Class<?> initializerContextClass =
					GenericTypeResolver.resolveTypeArgument(initializerClass, ApplicationContextInitializer.class);
			if (initializerContextClass != null && !initializerContextClass.isInstance(wac)) {
				throw new ApplicationContextException(String.format(
						"Could not apply context initializer [%s] since its generic parameter [%s] " +
						"is not assignable from the type of application context used by this " +
						"framework servlet: [%s]", initializerClass.getName(), initializerContextClass.getName(),
						wac.getClass().getName()));
			}
			return BeanUtils.instantiateClass(initializerClass, ApplicationContextInitializer.class);
		}
		catch (ClassNotFoundException ex) {
			throw new ApplicationContextException(String.format("Could not load class [%s] specified " +
					"via 'contextInitializerClasses' init-param", className), ex);
		}
	}

	
Return the ServletContext attribute name for this servlet's WebApplicationContext.

The default implementation returns SERVLET_CONTEXT_PREFIX + servlet name. 
See Also:
/**
	 * Return the ServletContext attribute name for this servlet's WebApplicationContext.
	 * <p>The default implementation returns
	 * {@code SERVLET_CONTEXT_PREFIX + servlet name}.
	 * @see #SERVLET_CONTEXT_PREFIX
	 * @see #getServletName
	 */
	public String getServletContextAttributeName() {
		return SERVLET_CONTEXT_PREFIX + getServletName();
	}

	
Return this servlet's WebApplicationContext.

/**
	 * Return this servlet's WebApplicationContext.
	 */
	@Nullable
	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
/**
	 * 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 Also:
/**
	 * 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.

The default implementation calls onRefresh, triggering a refresh of this servlet's context-dependent state. 
Params:
  • event – the incoming ApplicationContext event
/**
	 * 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;
		synchronized (this.onRefreshMonitor) {
			onRefresh(event.getApplicationContext());
		}
	}

	
Template method which can be overridden to add servlet-specific refresh work.
Called after successful context refresh.

This implementation is empty.

Params:
  • context – the current WebApplicationContext
See Also:
/**
	 * 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.
	}

	
Close the WebApplicationContext of this servlet.

See Also:
  • close.close()
/**
	 * Close the WebApplicationContext of this servlet.
	 * @see org.springframework.context.ConfigurableApplicationContext#close()
	 */
	@Override
	public void destroy() {
		getServletContext().log("Destroying Spring FrameworkServlet '" + getServletName() + "'");
		// Only call close() on WebApplicationContext if locally managed...
		if (this.webApplicationContext instanceof ConfigurableApplicationContext && !this.webApplicationContextInjected) {
			((ConfigurableApplicationContext) this.webApplicationContext).close();
		}
	}


	
Override the parent class implementation in order to intercept PATCH requests.

/**
	 * Override the parent class implementation in order to intercept PATCH requests.
	 */
	@Override
	protected void service(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		HttpMethod httpMethod = HttpMethod.resolve(request.getMethod());
		if (httpMethod == HttpMethod.PATCH || httpMethod == null) {
			processRequest(request, response);
		}
		else {
			super.service(request, response);
		}
	}

	
Delegate GET requests to processRequest/doService.

Will also be invoked by HttpServlet's default implementation of doHead, with a NoBodyResponse that just captures the content length. 
See Also:
/**
	 * Delegate GET requests to processRequest/doService.
	 * <p>Will also be invoked by HttpServlet's default implementation of {@code doHead},
	 * with a {@code NoBodyResponse} 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 processRequest. 
See Also:
/**
	 * 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 processRequest. 
See Also:
/**
	 * 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 processRequest. 
See Also:
/**
	 * 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 processRequest, if desired. 
Applies HttpServlet's standard OPTIONS processing otherwise,
and also if there is still no 'Allow' header set after dispatching.

See Also:
/**
	 * 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 || CorsUtils.isPreFlightRequest(request)) {
			processRequest(request, response);
			if (response.containsHeader("Allow")) {
				// Proper OPTIONS response coming from a handler - we're done.
				return;
			}
		}

		// Use response wrapper in order to always add PATCH to the allowed methods
		super.doOptions(request, new HttpServletResponseWrapper(response) {
			@Override
			public void setHeader(String name, String value) {
				if ("Allow".equals(name)) {
					value = (StringUtils.hasLength(value) ? value + ", " : "") + HttpMethod.PATCH.name();
				}
				super.setHeader(name, value);
			}
		});
	}

	
Delegate TRACE requests to processRequest, if desired. 
Applies HttpServlet's standard TRACE processing otherwise.

See Also:
/**
	 * 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.

The actual event handling is performed by the abstract doService template method. 
/**
	 * 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;

		LocaleContext previousLocaleContext = LocaleContextHolder.getLocaleContext();
		LocaleContext localeContext = buildLocaleContext(request);

		RequestAttributes previousAttributes = RequestContextHolder.getRequestAttributes();
		ServletRequestAttributes requestAttributes = buildRequestAttributes(request, response, previousAttributes);

		WebAsyncManager asyncManager = WebAsyncUtils.getAsyncManager(request);
		asyncManager.registerCallableInterceptor(FrameworkServlet.class.getName(), new RequestBindingInterceptor());

		initContextHolders(request, localeContext, requestAttributes);

		try {
			doService(request, response);
		}
		catch (ServletException | IOException ex) {
			failureCause = ex;
			throw ex;
		}
		catch (Throwable ex) {
			failureCause = ex;
			throw new NestedServletException("Request processing failed", ex);
		}

		finally {
			resetContextHolders(request, previousLocaleContext, previousAttributes);
			if (requestAttributes != null) {
				requestAttributes.requestCompleted();
			}
			logResult(request, response, failureCause, asyncManager);
			publishRequestHandledEvent(request, response, startTime, failureCause);
		}
	}

	
Build a LocaleContext for the given request, exposing the request's
primary locale as current locale.

Params:
  • request – current HTTP request
See Also:
Returns:the corresponding LocaleContext, or null if none to bind
/**
	 * 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, or {@code null} if none to bind
	 * @see LocaleContextHolder#setLocaleContext
	 */
	@Nullable
	protected LocaleContext buildLocaleContext(HttpServletRequest request) {
		return new SimpleLocaleContext(request.getLocale());
	}

	
Build ServletRequestAttributes for the given request (potentially also
holding a reference to the response), taking pre-bound attributes
(and their type) into consideration.

Params:
  • request – current HTTP request
  • response – current HTTP response
  • previousAttributes – pre-bound RequestAttributes instance, if any
See Also:
Returns:the ServletRequestAttributes to bind, or null to preserve the previously bound instance (or not binding any, if none bound before)
/**
	 * Build ServletRequestAttributes for the given request (potentially also
	 * holding a reference to the response), taking pre-bound attributes
	 * (and their type) into consideration.
	 * @param request current HTTP request
	 * @param response current HTTP response
	 * @param previousAttributes pre-bound RequestAttributes instance, if any
	 * @return the ServletRequestAttributes to bind, or {@code null} to preserve
	 * the previously bound instance (or not binding any, if none bound before)
	 * @see RequestContextHolder#setRequestAttributes
	 */
	@Nullable
	protected ServletRequestAttributes buildRequestAttributes(HttpServletRequest request,
			@Nullable HttpServletResponse response, @Nullable RequestAttributes previousAttributes) {

		if (previousAttributes == null || previousAttributes instanceof ServletRequestAttributes) {
			return new ServletRequestAttributes(request, response);
		}
		else {
			return null;  // preserve the pre-bound RequestAttributes instance
		}
	}

	private void initContextHolders(HttpServletRequest request,
			@Nullable LocaleContext localeContext, @Nullable RequestAttributes requestAttributes) {

		if (localeContext != null) {
			LocaleContextHolder.setLocaleContext(localeContext, this.threadContextInheritable);
		}
		if (requestAttributes != null) {
			RequestContextHolder.setRequestAttributes(requestAttributes, this.threadContextInheritable);
		}
	}

	private void resetContextHolders(HttpServletRequest request,
			@Nullable LocaleContext prevLocaleContext, @Nullable RequestAttributes previousAttributes) {

		LocaleContextHolder.setLocaleContext(prevLocaleContext, this.threadContextInheritable);
		RequestContextHolder.setRequestAttributes(previousAttributes, this.threadContextInheritable);
	}

	private void logResult(HttpServletRequest request, HttpServletResponse response,
			@Nullable Throwable failureCause, WebAsyncManager asyncManager) {

		if (!logger.isDebugEnabled()) {
			return;
		}

		String dispatchType = request.getDispatcherType().name();
		boolean initialDispatch = request.getDispatcherType().equals(DispatcherType.REQUEST);

		if (failureCause != null) {
			if (!initialDispatch) {
				// FORWARD/ERROR/ASYNC: minimal message (there should be enough context already)
				if (logger.isDebugEnabled()) {
					logger.debug("Unresolved failure from \"" + dispatchType + "\" dispatch: " + failureCause);
				}
			}
			else if (logger.isTraceEnabled()) {
				logger.trace("Failed to complete request", failureCause);
			}
			else {
				logger.debug("Failed to complete request: " + failureCause);
			}
			return;
		}

		if (asyncManager.isConcurrentHandlingStarted()) {
			logger.debug("Exiting but response remains open for further handling");
			return;
		}

		int status = response.getStatus();
		String headers = ""; // nothing below trace

		if (logger.isTraceEnabled()) {
			Collection<String> names = response.getHeaderNames();
			if (this.enableLoggingRequestDetails) {
				headers = names.stream().map(name -> name + ":" + response.getHeaders(name))
						.collect(Collectors.joining(", "));
			}
			else {
				headers = names.isEmpty() ? "" : "masked";
			}
			headers = ", headers={" + headers + "}";
		}

		if (!initialDispatch) {
			logger.debug("Exiting from \"" + dispatchType + "\" dispatch, status " + status + headers);
		}
		else {
			HttpStatus httpStatus = HttpStatus.resolve(status);
			logger.debug("Completed " + (httpStatus != null ? httpStatus : status) + headers);
		}
	}

	private void publishRequestHandledEvent(HttpServletRequest request, HttpServletResponse response,
			long startTime, @Nullable Throwable failureCause) {

		if (this.publishEvents && this.webApplicationContext != null) {
			// 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, response.getStatus()));
		}
	}

	
Determine the username for the given request.

The default implementation takes the name of the UserPrincipal, if any.
Can be overridden in subclasses.

Params:
  • request – current HTTP request
See Also:
Returns:the username, or null if none found
/**
	 * 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} if none found
	 * @see javax.servlet.http.HttpServletRequest#getUserPrincipal()
	 */
	@Nullable
	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.

The contract is essentially the same as that for the commonly overridden doGet or doPost methods of HttpServlet. 
This class intercepts calls to ensure that exception handling and
event publication takes place.

Params:
  • request – current HTTP request
  • response – current HTTP response
Throws:
  • Exception – in case of any kind of processing failure
See Also:
/**
	 * 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} or {@code doPost} 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;


	
ApplicationListener endpoint that receives events from this servlet's WebApplicationContext only, delegating to onApplicationEvent on the FrameworkServlet instance. 
/**
	 * ApplicationListener endpoint that receives events from this servlet's WebApplicationContext
	 * only, delegating to {@code onApplicationEvent} on the FrameworkServlet instance.
	 */
	private class ContextRefreshListener implements ApplicationListener<ContextRefreshedEvent> {

		@Override
		public void onApplicationEvent(ContextRefreshedEvent event) {
			FrameworkServlet.this.onApplicationEvent(event);
		}
	}


	
CallableProcessingInterceptor implementation that initializes and resets
FrameworkServlet's context holders, i.e. LocaleContextHolder and RequestContextHolder.

/**
	 * CallableProcessingInterceptor implementation that initializes and resets
	 * FrameworkServlet's context holders, i.e. LocaleContextHolder and RequestContextHolder.
	 */
	private class RequestBindingInterceptor implements CallableProcessingInterceptor {

		@Override
		public <T> void preProcess(NativeWebRequest webRequest, Callable<T> task) {
			HttpServletRequest request = webRequest.getNativeRequest(HttpServletRequest.class);
			if (request != null) {
				HttpServletResponse response = webRequest.getNativeResponse(HttpServletResponse.class);
				initContextHolders(request, buildLocaleContext(request),
						buildRequestAttributes(request, response, null));
			}
		}
		@Override
		public <T> void postProcess(NativeWebRequest webRequest, Callable<T> task, Object concurrentResult) {
			HttpServletRequest request = webRequest.getNativeRequest(HttpServletRequest.class);
			if (request != null) {
				resetContextHolders(request, null, null);
			}
		}
	}

}