Spring Web 6.1.4 · org.springframework.web.context.ContextLoader

Performs the actual initialization work for the root application context. Called by ContextLoaderListener.

Looks for a "contextClass" parameter at the web.xml context-param level to specify the context class type, falling back to org.springframework.web.context.support.XmlWebApplicationContext if not found. With the default ContextLoader implementation, any context class specified needs to implement the ConfigurableWebApplicationContext interface.

Processes a "contextConfigLocation" context-param and passes its value to the context instance, parsing it into potentially multiple file paths which can be separated by any number of commas and spaces, e.g. "WEB-INF/applicationContext1.xml, WEB-INF/applicationContext2.xml". Ant-style path patterns are supported as well, e.g. "WEB-INF/*Context.xml,WEB-INF/spring*.xml" or "WEB-INF/**/*Context.xml". If not explicitly specified, the context implementation is supposed to use a default location (with XmlWebApplicationContext: "/WEB-INF/applicationContext.xml").

Note

In case of multiple config locations, later bean definitions will override ones defined in previously loaded files, at least when using one of Spring's default ApplicationContext implementations. This can be leveraged to deliberately override certain bean definitions via an extra XML file.

Above and beyond loading the root application context, this class can optionally load or obtain and hook up a shared parent context to the root application context. See the loadParentContext(ServletContext) method for more information.

ContextLoader supports injecting the root web application context via the ContextLoader(WebApplicationContext) constructor, allowing for programmatic configuration in Servlet initializers. See org.springframework.web.WebApplicationInitializer for usage examples.

Field Summary

Modifier and Type	Field and Description
public static final String	CONFIG_LOCATION_PARAM Name of servlet context parameter (i.e., contextConfigLocation) that can specify the config location for the root context, falling back to the implementation's default otherwise.
private WebApplicationContext	context The root WebApplicationContext instance that this loader manages.
public static final String	CONTEXT_CLASS_PARAM Config param for the root WebApplicationContext implementation class to use: contextClass.
public static final String	CONTEXT_ID_PARAM Config param for the root WebApplicationContext id, to be used as serialization id for the underlying BeanFactory: contextId.
public static final String	CONTEXT_INITIALIZER_CLASSES_PARAM Config param for `ApplicationContextInitializer` classes to use for initializing the root web application context: contextInitializerClasses.
private final List<ApplicationContextInitializer<ConfigurableApplicationContext>>	contextInitializers Actual ApplicationContextInitializer instances to apply to the context.
private static volatile WebApplicationContext	currentContext The 'current' WebApplicationContext, if the ContextLoader class is deployed in the web app ClassLoader itself.
private static final Map<ClassLoader, WebApplicationContext>	currentContextPerThread Map from (thread context) ClassLoader to corresponding 'current' WebApplicationContext.
private static final String	DEFAULT_STRATEGIES_PATH Name of the class path resource (relative to the ContextLoader class) that defines ContextLoader's default strategy names.
private static Properties	defaultStrategies
public static final String	GLOBAL_INITIALIZER_CLASSES_PARAM Config param for global `ApplicationContextInitializer` classes to use for initializing all web application contexts in the current application: globalInitializerClasses.
private static final String	INIT_PARAM_DELIMITERS Any number of these characters are considered delimiters between multiple values in a single init-param String value.

Constructor Summary

Access	Constructor and Description
public	ContextLoader() Create a new `ContextLoader` that will create a web application context based on the "contextClass" and "contextConfigLocation" servlet context-params.
public	ContextLoader(WebApplicationContext the application context to manage context) Create a new `ContextLoader` with the given application context.

Method Summary

Modifier and Type	Method and Description
public void	closeWebApplicationContext(ServletContext the ServletContext that the WebApplicationContext runs in servletContext) Close Spring's web application context for the given servlet context.
protected void	configureAndRefreshWebApplicationContext(ConfigurableWebApplicationContext wac, ServletContext sc)
protected WebApplicationContext	Returns: the root WebApplicationContext createWebApplicationContext(ServletContext current servlet context sc) Instantiate the root WebApplicationContext for this loader, either the default context class or a custom context class if specified.
protected void	customizeContext(ServletContext the current servlet context sc, ConfigurableWebApplicationContext the newly created application context wac) Customize the `ConfigurableWebApplicationContext` created by this ContextLoader after config locations have been supplied to the context but before the context is refreshed.
protected Class<?>	Returns: the WebApplicationContext implementation class to use determineContextClass(ServletContext current servlet context servletContext) Return the WebApplicationContext implementation class to use, either the default XmlWebApplicationContext or a custom context class if specified.
protected List<Class<ApplicationContextInitializer<ConfigurableApplicationContext>>>	determineContextInitializerClasses(ServletContext current servlet context servletContext) Return the `ApplicationContextInitializer` implementation classes to use if any have been specified by `CONTEXT_INITIALIZER_CLASSES_PARAM`.
public static WebApplicationContext	Returns: the current root web application context, or `null` if none found getCurrentWebApplicationContext() Obtain the Spring root web application context for the current thread (i.e. for the current thread's context ClassLoader, which needs to be the web application's ClassLoader).
public WebApplicationContext	Returns: the new WebApplicationContext initWebApplicationContext(ServletContext current servlet context servletContext) Initialize Spring's web application context for the given servlet context, using the application context provided at construction time, or creating a new one according to the "`contextClass`" and "`contextConfigLocation`" context-params.
private Class<ApplicationContextInitializer<ConfigurableApplicationContext>>	loadInitializerClass(String className)
protected ApplicationContext	Returns: the parent application context, or `null` if none loadParentContext(ServletContext current servlet context servletContext) Template method with default implementation (which may be overridden by a subclass), to load or obtain an ApplicationContext instance which will be used as the parent context of the root WebApplicationContext.
public void	setContextInitializers(ApplicationContextInitializer<?>... initializers) Specify which `ApplicationContextInitializer` instances should be used to initialize the application context used by this `ContextLoader`.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

CONFIG_LOCATION_PARAM back to summary

CONFIG_LOCATION_PARAM	back to summary
public static final String CONFIG_LOCATION_PARAM Name of servlet context parameter (i.e., contextConfigLocation) that can specify the config location for the root context, falling back to the implementation's default otherwise. See Also `org.springframework.web.context.support.XmlWebApplicationContext#DEFAULT_CONFIG_LOCATION`

public static final String CONFIG_LOCATION_PARAM

Name of servlet context parameter (i.e., contextConfigLocation) that can specify the config location for the root context, falling back to the implementation's default otherwise.

See Also: org.springframework.web.context.support.XmlWebApplicationContext#DEFAULT_CONFIG_LOCATION

context	back to summary
private WebApplicationContext context The root WebApplicationContext instance that this loader manages. Annotations @Nullable

CONTEXT_CLASS_PARAM back to summary

CONTEXT_CLASS_PARAM	back to summary
public static final String CONTEXT_CLASS_PARAM Config param for the root WebApplicationContext implementation class to use: contextClass. See Also `determineContextClass(ServletContext)`

public static final String CONTEXT_CLASS_PARAM

Config param for the root WebApplicationContext implementation class to use: contextClass.

See Also: determineContextClass(ServletContext)

CONTEXT_ID_PARAM	back to summary
public static final String CONTEXT_ID_PARAM Config param for the root WebApplicationContext id, to be used as serialization id for the underlying BeanFactory: contextId.

CONTEXT_INITIALIZER_CLASSES_PARAM back to summary

CONTEXT_INITIALIZER_CLASSES_PARAM	back to summary
public static final String CONTEXT_INITIALIZER_CLASSES_PARAM Config param for `ApplicationContextInitializer` classes to use for initializing the root web application context: contextInitializerClasses. See Also `customizeContext(ServletContext, ConfigurableWebApplicationContext)`

public static final String CONTEXT_INITIALIZER_CLASSES_PARAM

Config param for ApplicationContextInitializer classes to use for initializing the root web application context: contextInitializerClasses.

See Also: customizeContext(ServletContext, ConfigurableWebApplicationContext)

contextInitializers	back to summary
private final List<ApplicationContextInitializer<ConfigurableApplicationContext>> contextInitializers Actual ApplicationContextInitializer instances to apply to the context.

currentContext	back to summary
private static volatile WebApplicationContext currentContext The 'current' WebApplicationContext, if the ContextLoader class is deployed in the web app ClassLoader itself. Annotations @Nullable

currentContextPerThread	back to summary
private static final Map<ClassLoader, WebApplicationContext> currentContextPerThread Map from (thread context) ClassLoader to corresponding 'current' WebApplicationContext.

DEFAULT_STRATEGIES_PATH	back to summary
private static final String DEFAULT_STRATEGIES_PATH Name of the class path resource (relative to the ContextLoader class) that defines ContextLoader's default strategy names.

defaultStrategies	back to summary
private static Properties defaultStrategies Annotations @Nullable

GLOBAL_INITIALIZER_CLASSES_PARAM back to summary

GLOBAL_INITIALIZER_CLASSES_PARAM	back to summary
public static final String GLOBAL_INITIALIZER_CLASSES_PARAM Config param for global `ApplicationContextInitializer` classes to use for initializing all web application contexts in the current application: globalInitializerClasses. See Also `customizeContext(ServletContext, ConfigurableWebApplicationContext)`

public static final String GLOBAL_INITIALIZER_CLASSES_PARAM

Config param for global ApplicationContextInitializer classes to use for initializing all web application contexts in the current application: globalInitializerClasses.

See Also: customizeContext(ServletContext, ConfigurableWebApplicationContext)

INIT_PARAM_DELIMITERS	back to summary
private static final String INIT_PARAM_DELIMITERS Any number of these characters are considered delimiters between multiple values in a single init-param String value.

Constructor Detail

ContextLoader back to summary

ContextLoader	back to summary
public ContextLoader() Create a new `ContextLoader` that will create a web application context based on the "contextClass" and "contextConfigLocation" servlet context-params. See class-level documentation for details on default values for each. This constructor is typically used when declaring the `ContextLoaderListener` subclass as a `<listener>` within `web.xml`, as a no-arg constructor is required. The created application context will be registered into the ServletContext under the attribute name `WebApplicationContext#ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE` and subclasses are free to call the `closeWebApplicationContext` method on container shutdown to close the application context. See Also `ContextLoader(WebApplicationContext)`, `initWebApplicationContext(ServletContext)`, `closeWebApplicationContext(ServletContext)`

public ContextLoader()

Create a new ContextLoader that will create a web application context based on the "contextClass" and "contextConfigLocation" servlet context-params. See class-level documentation for details on default values for each.

This constructor is typically used when declaring the ContextLoaderListener subclass as a <listener> within web.xml, as a no-arg constructor is required.

The created application context will be registered into the ServletContext under the attribute name WebApplicationContext#ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE and subclasses are free to call the closeWebApplicationContext method on container shutdown to close the application context.

See Also: ContextLoader(WebApplicationContext), initWebApplicationContext(ServletContext), closeWebApplicationContext(ServletContext)

ContextLoader back to summary

ContextLoader	back to summary
public ContextLoader(WebApplicationContext context) Create a new `ContextLoader` with the given application context. This constructor is useful in Servlet initializers where instance-based registration of listeners is possible through the `ServletContext#addListener` API. The 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 has not already been assigned an id, one will be assigned to it `ServletContext` and `ServletConfig` objects will be delegated to the application context `customizeContext` will be called Any `ApplicationContextInitializers` specified through the "contextInitializerClasses" init-param 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 `org.springframework.web.WebApplicationInitializer` for usage examples. In any case, the given application context will be registered into the ServletContext under the attribute name `WebApplicationContext#ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE` and subclasses are free to call the `closeWebApplicationContext` method on container shutdown to close the application context. Parameters context:WebApplicationContext the application context to manage See Also `initWebApplicationContext(ServletContext)`, `closeWebApplicationContext(ServletContext)`

public ContextLoader(WebApplicationContext context)

Create a new ContextLoader with the given application context. This constructor is useful in Servlet initializers where instance-based registration of listeners is possible through the ServletContext#addListener API.

The 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 has not already been assigned an id, one will be assigned to it
ServletContext and ServletConfig objects will be delegated to the application context
customizeContext will be called
Any ApplicationContextInitializers specified through the "contextInitializerClasses" init-param 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 org.springframework.web.WebApplicationInitializer for usage examples.

In any case, the given application context will be registered into the ServletContext under the attribute name WebApplicationContext#ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE and subclasses are free to call the closeWebApplicationContext method on container shutdown to close the application context.

Parameters

context:WebApplicationContext: the application context to manage

Method Detail

closeWebApplicationContext back to summary

closeWebApplicationContext	back to summary
public void closeWebApplicationContext(ServletContext servletContext) Close Spring's web application context for the given servlet context. If overriding `loadParentContext(ServletContext)`, you may have to override this method as well. Parameters servletContext:ServletContext the ServletContext that the WebApplicationContext runs in

public void closeWebApplicationContext(ServletContext servletContext)

Close Spring's web application context for the given servlet context.

If overriding loadParentContext(ServletContext), you may have to override this method as well.

Parameters

servletContext:ServletContext: the ServletContext that the WebApplicationContext runs in

configureAndRefreshWebApplicationContext	back to summary
protected void configureAndRefreshWebApplicationContext(ConfigurableWebApplicationContext wac, ServletContext sc)

createWebApplicationContext back to summary

createWebApplicationContext	back to summary
protected WebApplicationContext createWebApplicationContext(ServletContext sc) Instantiate the root WebApplicationContext for this loader, either the default context class or a custom context class if specified. This implementation expects custom contexts to implement the `ConfigurableWebApplicationContext` interface. Can be overridden in subclasses. In addition, `customizeContext` gets called prior to refreshing the context, allowing subclasses to perform custom modifications to the context. Parameters sc:ServletContext current servlet context Returns:WebApplicationContext the root WebApplicationContext See Also `ConfigurableWebApplicationContext`

protected WebApplicationContext createWebApplicationContext(ServletContext sc)

Instantiate the root WebApplicationContext for this loader, either the default context class or a custom context class if specified.

This implementation expects custom contexts to implement the ConfigurableWebApplicationContext interface. Can be overridden in subclasses.

In addition, customizeContext gets called prior to refreshing the context, allowing subclasses to perform custom modifications to the context.

Parameters

sc:ServletContext: current servlet context

Returns:WebApplicationContext

the root WebApplicationContext

See Also

ConfigurableWebApplicationContext

customizeContext back to summary

customizeContext	back to summary
protected void customizeContext(ServletContext sc, ConfigurableWebApplicationContext wac) Customize the `ConfigurableWebApplicationContext` created by this ContextLoader after config locations have been supplied to the context but before the context is refreshed. The default implementation determines what (if any) context initializer classes have been specified through context init parameters and invokes each with the given web application context. Any `ApplicationContextInitializers` implementing `Ordered` or marked with @`Order` will be sorted appropriately. Parameters sc:ServletContext the current servlet context wac:ConfigurableWebApplicationContext the newly created application context See Also `CONTEXT_INITIALIZER_CLASSES_PARAM`, `ApplicationContextInitializer#initialize(ConfigurableApplicationContext)`

protected void customizeContext(ServletContext sc, ConfigurableWebApplicationContext wac)

Customize the ConfigurableWebApplicationContext created by this ContextLoader after config locations have been supplied to the context but before the context is refreshed.

The default implementation determines what (if any) context initializer classes have been specified through context init parameters and invokes each with the given web application context.

Any ApplicationContextInitializers implementing Ordered or marked with @Order will be sorted appropriately.

Parameters

sc:ServletContext: the current servlet context
wac:ConfigurableWebApplicationContext: the newly created application context

determineContextClass back to summary

determineContextClass	back to summary
protected Class<?> determineContextClass(ServletContext servletContext) Return the WebApplicationContext implementation class to use, either the default XmlWebApplicationContext or a custom context class if specified. Parameters servletContext:ServletContext current servlet context Returns:Class<?> the WebApplicationContext implementation class to use See Also `CONTEXT_CLASS_PARAM`, `org.springframework.web.context.support.XmlWebApplicationContext`

protected Class<?> determineContextClass(ServletContext servletContext)

Return the WebApplicationContext implementation class to use, either the default XmlWebApplicationContext or a custom context class if specified.

Parameters

servletContext:ServletContext: current servlet context

Returns:Class<?>

the WebApplicationContext implementation class to use

determineContextInitializerClasses back to summary

determineContextInitializerClasses	back to summary
protected List<Class<ApplicationContextInitializer<ConfigurableApplicationContext>>> determineContextInitializerClasses(ServletContext servletContext) Return the `ApplicationContextInitializer` implementation classes to use if any have been specified by `CONTEXT_INITIALIZER_CLASSES_PARAM`. Parameters servletContext:ServletContext current servlet context See Also `CONTEXT_INITIALIZER_CLASSES_PARAM`

protected List<Class<ApplicationContextInitializer<ConfigurableApplicationContext>>> determineContextInitializerClasses(ServletContext servletContext)

Return the ApplicationContextInitializer implementation classes to use if any have been specified by CONTEXT_INITIALIZER_CLASSES_PARAM.

Parameters

servletContext:ServletContext: current servlet context

See Also

CONTEXT_INITIALIZER_CLASSES_PARAM

getCurrentWebApplicationContext back to summary

getCurrentWebApplicationContext	back to summary
public static WebApplicationContext getCurrentWebApplicationContext() Obtain the Spring root web application context for the current thread (i.e. for the current thread's context ClassLoader, which needs to be the web application's ClassLoader). Returns:WebApplicationContext the current root web application context, or `null` if none found Annotations @Nullable See Also `org.springframework.web.context.support.SpringBeanAutowiringSupport`

public static WebApplicationContext getCurrentWebApplicationContext()

Obtain the Spring root web application context for the current thread (i.e. for the current thread's context ClassLoader, which needs to be the web application's ClassLoader).

Returns:WebApplicationContext

the current root web application context, or null if none found

Annotations

@Nullable

initWebApplicationContext back to summary

initWebApplicationContext	back to summary
public WebApplicationContext initWebApplicationContext(ServletContext servletContext) Initialize Spring's web application context for the given servlet context, using the application context provided at construction time, or creating a new one according to the "`contextClass`" and "`contextConfigLocation`" context-params. Parameters servletContext:ServletContext current servlet context Returns:WebApplicationContext the new WebApplicationContext See Also `ContextLoader(WebApplicationContext)`, `CONTEXT_CLASS_PARAM`, `CONFIG_LOCATION_PARAM`

public WebApplicationContext initWebApplicationContext(ServletContext servletContext)

Initialize Spring's web application context for the given servlet context, using the application context provided at construction time, or creating a new one according to the "contextClass" and "contextConfigLocation" context-params.

Parameters

servletContext:ServletContext: current servlet context

Returns:WebApplicationContext

the new WebApplicationContext

loadInitializerClass	back to summary
private Class<ApplicationContextInitializer<ConfigurableApplicationContext>> loadInitializerClass(String className) Annotations @SuppressWarnings:unchecked

loadParentContext back to summary

loadParentContext	back to summary
protected ApplicationContext loadParentContext(ServletContext servletContext) Template method with default implementation (which may be overridden by a subclass), to load or obtain an ApplicationContext instance which will be used as the parent context of the root WebApplicationContext. If the return value from the method is null, no parent context is set. The main reason to load a parent context here is to allow multiple root web application contexts to all be children of a shared EAR context, or alternately to also share the same parent context that is visible to EJBs. For pure web applications, there is usually no need to worry about having a parent context to the root web application context. The default implementation simply returns `null`, as of 5.0. Parameters servletContext:ServletContext current servlet context Returns:ApplicationContext the parent application context, or `null` if none Annotations @Nullable

protected ApplicationContext loadParentContext(ServletContext servletContext)

Template method with default implementation (which may be overridden by a subclass), to load or obtain an ApplicationContext instance which will be used as the parent context of the root WebApplicationContext. If the return value from the method is null, no parent context is set.

The main reason to load a parent context here is to allow multiple root web application contexts to all be children of a shared EAR context, or alternately to also share the same parent context that is visible to EJBs. For pure web applications, there is usually no need to worry about having a parent context to the root web application context.

The default implementation simply returns null, as of 5.0.

Parameters

servletContext:ServletContext: current servlet context

Returns:ApplicationContext

the parent application context, or null if none

Annotations

@Nullable

setContextInitializers back to summary

setContextInitializers	back to summary
public void setContextInitializers(ApplicationContextInitializer<?>... initializers) Specify which `ApplicationContextInitializer` instances should be used to initialize the application context used by this `ContextLoader`. Annotations @SuppressWarnings:unchecked Since 4.2 See Also `configureAndRefreshWebApplicationContext`, `customizeContext`

public void setContextInitializers(ApplicationContextInitializer<?>... initializers)

Specify which ApplicationContextInitializer instances should be used to initialize the application context used by this ContextLoader.

Annotations

@SuppressWarnings:unchecked

Since

4.2

public Class ContextLoader

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