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Introduce Framework/DispatcherServlet constructors

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Constructors have been added to both FrameworkServlet and
DispatcherServlet to support instance-based programmatic registration
of Servlets within ServletContainerInitializer implementations in
Servlet 3.0+ environments, and more particularly when using Spring 3.1's
WebApplicationInitializer SPI.

This change also renames the method added to FrameworkServlet in
SPR-8185 from #initializeWebApplicationContext to #applyInitializers.
The reason being that a method named #initWebApplicationContext was
already present and the names overlapped confusingly.

Issue: SPR-7672, SPR-8185
This commit is contained in:
Chris Beams
2011-05-30 12:54:48 +00:00
parent c4d98278e9
commit 2eea63eec5
2 changed files with 233 additions and 31 deletions
Download Patch File Download Diff File Expand all files Collapse all files

74
org.springframework.web.servlet/src/main/java/org/springframework/web/servlet/DispatcherServlet.java
View File

@@ -28,17 +28,18 @@ import java.util.Locale;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.BeanFactoryUtils;
import org.springframework.beans.factory.BeanInitializationException;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.i18n.LocaleContext;
import org.springframework.core.OrderComparator;
import org.springframework.core.io.ClassPathResource;
@@ -46,6 +47,7 @@ import org.springframework.core.io.support.PropertiesLoaderUtils;
import org.springframework.ui.context.ThemeSource;
import org.springframework.util.ClassUtils;
import org.springframework.util.StringUtils;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.request.ServletWebRequest;
import org.springframework.web.multipart.MultipartException;
import org.springframework.web.multipart.MultipartHttpServletRequest;
@@ -118,9 +120,15 @@ import org.springframework.web.util.WebUtils;
* namespace, loading its own application context with mappings, handlers, etc. Only the root application context as
* loaded by {@link org.springframework.web.context.ContextLoaderListener}, if any, will be shared.
*
* <p>As of Spring 3.1, {@code DispatcherServlet} 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 #DispatcherServlet(WebApplicationContext)} Javadoc for details.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @author Rob Harrop
* @author Chris Beams
* @see org.springframework.web.HttpRequestHandler
* @see org.springframework.web.servlet.mvc.Controller
* @see org.springframework.web.context.ContextLoaderListener
@@ -265,6 +273,70 @@ public class DispatcherServlet extends FrameworkServlet {
private List<ViewResolver> viewResolvers;
/**
* Create a new {@code DispatcherServlet} 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 {@code ApplicationContextInitializer} classes should be used to
* further configure the internal application context prior to refresh().
* @see #DispatcherServlet(WebApplicationContext)
*/
public DispatcherServlet() {
super();
}
/**
* Create a new {@code DispatcherServlet} 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 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 {@code 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 if the
* context implements {@link ConfigurableApplicationContext}</li>
* </ul>
* If the context has already been refreshed, none of the above will occur, under the
* assumption that the user has performed these actions (or not) per their 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 DispatcherServlet(WebApplicationContext webApplicationContext) {
super(webApplicationContext);
}
/**
* Set whether to detect all HandlerMapping beans in this servlet's context. Otherwise,
* just a single bean with name "handlerMapping" will be expected.

190
org.springframework.web.servlet/src/main/java/org/springframework/web/servlet/FrameworkServlet.java
View File

@@ -18,6 +18,7 @@ package org.springframework.web.servlet;
import java.io.IOException;
import java.security.Principal;
import java.util.TreeSet;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
@@ -35,7 +36,9 @@ 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;
@@ -100,6 +103,11 @@ import org.springframework.web.util.WebUtils;
* 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
@@ -172,8 +180,77 @@ public abstract class FrameworkServlet extends HttpServletBean {
/** 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 TreeSet<ApplicationContextInitializer<ConfigurableApplicationContext>> contextInitializers =
new TreeSet<ApplicationContextInitializer<ConfigurableApplicationContext>>(new AnnotationAwareOrderComparator());
/**
* 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
@@ -230,12 +307,25 @@ public abstract class FrameworkServlet extends HttpServletBean {
/**
* Specify the set of fully-qualified {@link ApplicationContextInitializer} class
* names, per the optional "contextInitializerClasses" servlet init-param.
* @see #createWebApplicationContext
* @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
@@ -362,21 +452,48 @@ public abstract class FrameworkServlet extends HttpServletBean {
* <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 wac = findWebApplicationContext();
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 fixed context defined for this servlet - create a local one.
WebApplicationContext parent =
WebApplicationContextUtils.getWebApplicationContext(getServletContext());
wac = createWebApplicationContext(parent);
// 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) {
// Apparently not a ConfigurableApplicationContext with refresh support:
// triggering initial onRefresh manually here.
// 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);
}
@@ -447,39 +564,48 @@ public abstract class FrameworkServlet extends HttpServletBean {
ConfigurableWebApplicationContext wac =
(ConfigurableWebApplicationContext) BeanUtils.instantiateClass(contextClass);
// Assign the best possible id value.
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());
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
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 {
wac.setId(ConfigurableWebApplicationContext.APPLICATION_CONTEXT_ID_PREFIX + getServletName());
// Servlet 2.5's getContextPath available!
wac.setId(ConfigurableWebApplicationContext.APPLICATION_CONTEXT_ID_PREFIX + sc.getContextPath() +
"/" + getServletName());
}
}
else {
// Servlet 2.5's getContextPath available!
wac.setId(ConfigurableWebApplicationContext.APPLICATION_CONTEXT_ID_PREFIX + sc.getContextPath() +
"/" + getServletName());
}
wac.setParent(parent);
wac.setServletContext(getServletContext());
wac.setServletConfig(getServletConfig());
wac.setNamespace(getNamespace());
wac.setConfigLocation(getContextConfigLocation());
wac.addApplicationListener(new SourceFilteringListener(wac, new ContextRefreshListener()));
postProcessWebApplicationContext(wac);
initializeWebApplicationContext(wac);
applyInitializers(wac);
wac.refresh();
return wac;
}
/**
@@ -506,10 +632,10 @@ public abstract class FrameworkServlet extends HttpServletBean {
* @param wac the configured WebApplicationContext (not refreshed yet)
* @see #createWebApplicationContext
* @see #postProcessWebApplicationContext
* @see ConfigurableWebApplicationContext#refresh()
* @see ConfigurableApplicationContext#refresh()
*/
@SuppressWarnings("unchecked")
protected void initializeWebApplicationContext(ConfigurableWebApplicationContext wac) {
protected void applyInitializers(ConfigurableApplicationContext wac) {
if (this.contextInitializerClasses != null) {
String[] initializerClassNames = StringUtils.tokenizeToStringArray(this.contextInitializerClasses, INIT_PARAM_DELIMITERS);
for(String initializerClassName : initializerClassNames) {
@@ -522,9 +648,13 @@ public abstract class FrameworkServlet extends HttpServletBean {
String.format("Could not instantiate class [%s] specified via " +
"'contextInitializerClasses' init-param", initializerClassName), ex);
}
initializer.initialize(wac);
this.contextInitializers.add(initializer);
}
}
for (ApplicationContextInitializer<ConfigurableApplicationContext> initializer : this.contextInitializers) {
initializer.initialize(wac);
}
}
/**