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java.lang.Objectorg.springframework.web.filter.GenericFilterBean
org.springframework.web.filter.DelegatingFilterProxy
public class DelegatingFilterProxy
Proxy for a standard Servlet 2.3 Filter, delegating to a Spring-managed
bean that implements the Filter interface. Supports a "targetBeanName"
filter init-param in web.xml, specifying the name of the
target bean in the Spring application context.
web.xml will usually contain a DelegatingFilterProxy definition,
with the specified filter-name corresponding to a bean name in
Spring's root application context. All calls to the filter proxy will then
be delegated to that bean in the Spring context, which is required to implement
the standard Servlet 2.3 Filter interface.
This approach is particularly useful for Filter implementation with complex setup needs, allowing to apply the full Spring bean definition machinery to Filter instances. Alternatively, consider standard Filter setup in combination with looking up service beans from the Spring root application context.
NOTE: The lifecycle methods defined by the Servlet Filter interface
will by default not be delegated to the target bean, relying on the
Spring application context to manage the lifecycle of that bean. Specifying
the "targetFilterLifecycle" filter init-param as "true" will enforce invocation
of the Filter.init and Filter.destroy lifecycle methods
on the target bean, letting the servlet container manage the filter lifecycle.
As of Spring 3.1, DelegatingFilterProxy has been updated to optionally accept
constructor parameters when using Servlet 3.0's instance-based filter registration
methods, usually in conjunction with Spring 3.1's
WebApplicationInitializer SPI. These constructors allow
for providing the delegate Filter bean directly, or providing the application context
and bean name to fetch, avoiding the need to look up the application context from the
ServletContext.
This class was originally inspired by Spring Security's FilterToBeanProxy
class, written by Ben Alex.
setTargetBeanName(java.lang.String),
setTargetFilterLifecycle(boolean),
Filter.doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain),
Filter.init(javax.servlet.FilterConfig),
Filter.destroy(),
DelegatingFilterProxy(Filter),
DelegatingFilterProxy(String),
DelegatingFilterProxy(String, WebApplicationContext),
javax.servlet.ServletContext#addFilter(String, Filter),
WebApplicationInitializer| Field Summary |
|---|
| Fields inherited from class org.springframework.web.filter.GenericFilterBean |
|---|
logger |
| Constructor Summary | |
|---|---|
DelegatingFilterProxy()
Create a new DelegatingFilterProxy. |
|
DelegatingFilterProxy(Filter delegate)
Create a new DelegatingFilterProxy with the given Filter delegate. |
|
DelegatingFilterProxy(String targetBeanName)
Create a new DelegatingFilterProxy that will retrieve the named target
bean from the Spring WebApplicationContext found in the ServletContext
(either the 'root' application context or the context named by
setContextAttribute(java.lang.String)). |
|
DelegatingFilterProxy(String targetBeanName,
WebApplicationContext wac)
Create a new DelegatingFilterProxy that will retrieve the named target
bean from the given Spring WebApplicationContext. |
|
| Method Summary | |
|---|---|
void |
destroy()
Subclasses may override this to perform custom filter shutdown. |
protected void |
destroyDelegate(Filter delegate)
Destroy the Filter delegate. |
void |
doFilter(ServletRequest request,
ServletResponse response,
FilterChain filterChain)
|
protected WebApplicationContext |
findWebApplicationContext()
Return the WebApplicationContext passed in at construction time, if available. |
String |
getContextAttribute()
Return the name of the ServletContext attribute which should be used to retrieve the WebApplicationContext from which to load the delegate Filter bean. |
protected String |
getTargetBeanName()
Return the name of the target bean in the Spring application context. |
protected Filter |
initDelegate(WebApplicationContext wac)
Initialize the Filter delegate, defined as bean the given Spring application context. |
protected void |
initFilterBean()
Subclasses may override this to perform custom initialization. |
protected void |
invokeDelegate(Filter delegate,
ServletRequest request,
ServletResponse response,
FilterChain filterChain)
Actually invoke the delegate Filter with the given request and response. |
protected boolean |
isTargetFilterLifecycle()
Return whether to invoke the Filter.init and
Filter.destroy lifecycle methods on the target bean. |
void |
setContextAttribute(String contextAttribute)
Set the name of the ServletContext attribute which should be used to retrieve the WebApplicationContext from which to load the delegate Filter bean. |
void |
setTargetBeanName(String targetBeanName)
Set the name of the target bean in the Spring application context. |
void |
setTargetFilterLifecycle(boolean targetFilterLifecycle)
Set whether to invoke the Filter.init and
Filter.destroy lifecycle methods on the target bean. |
| Methods inherited from class org.springframework.web.filter.GenericFilterBean |
|---|
addRequiredProperty, afterPropertiesSet, getFilterConfig, getFilterName, getServletContext, init, initBeanWrapper, setBeanName, setEnvironment, setServletContext |
| Methods inherited from class java.lang.Object |
|---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Constructor Detail |
|---|
public DelegatingFilterProxy()
DelegatingFilterProxy. For traditional (pre-Servlet 3.0) use
in web.xml.
setTargetBeanName(String)public DelegatingFilterProxy(Filter delegate)
DelegatingFilterProxy with the given Filter delegate.
Bypasses entirely the need for interacting with a Spring application context,
specifying the target bean name, etc.
For use in Servlet 3.0+ environments where instance-based registration of filters is supported.
delegate - the Filter instance that this proxy will delegate to and
manage the lifecycle for (must not be null).doFilter(ServletRequest, ServletResponse, FilterChain),
invokeDelegate(Filter, ServletRequest, ServletResponse, FilterChain),
destroy(),
GenericFilterBean.setEnvironment(org.springframework.core.env.Environment)public DelegatingFilterProxy(String targetBeanName)
DelegatingFilterProxy that will retrieve the named target
bean from the Spring WebApplicationContext found in the ServletContext
(either the 'root' application context or the context named by
setContextAttribute(java.lang.String)).
For use in Servlet 3.0+ environments where instance-based registration of filters is supported.
The target bean must implement the standard Servlet Filter.
targetBeanName - name of the target filter bean to look up in the Spring
application context (must not be null).findWebApplicationContext(),
GenericFilterBean.setEnvironment(org.springframework.core.env.Environment)
public DelegatingFilterProxy(String targetBeanName,
WebApplicationContext wac)
DelegatingFilterProxy that will retrieve the named target
bean from the given Spring WebApplicationContext.
For use in Servlet 3.0+ environments where instance-based registration of filters is supported.
The target bean must implement the standard Servlet Filter interface.
The given WebApplicationContext may or may not be refreshed when passed
in. If it has not, and if the context implements ConfigurableApplicationContext,
a refresh() will be attempted before
retrieving the named target bean.
This proxy's Environment will be inherited from the given
WebApplicationContext.
targetBeanName - name of the target filter bean in the Spring application
context (must not be null).wac - the application context from which the target filter will be retrieved;
if null, an application context will be looked up from ServletContext
as a fallback.findWebApplicationContext(),
GenericFilterBean.setEnvironment(org.springframework.core.env.Environment)| Method Detail |
|---|
public void setContextAttribute(String contextAttribute)
WebApplicationContext from which to load the delegate Filter bean.
public String getContextAttribute()
WebApplicationContext from which to load the delegate Filter bean.
public void setTargetBeanName(String targetBeanName)
By default, the filter-name as specified for the
DelegatingFilterProxy in web.xml will be used.
protected String getTargetBeanName()
public void setTargetFilterLifecycle(boolean targetFilterLifecycle)
Filter.init and
Filter.destroy lifecycle methods on the target bean.
Default is "false"; target beans usually rely on the Spring application context for managing their lifecycle. Setting this flag to "true" means that the servlet container will control the lifecycle of the target Filter, with this proxy delegating the corresponding calls.
protected boolean isTargetFilterLifecycle()
Filter.init and
Filter.destroy lifecycle methods on the target bean.
protected void initFilterBean()
throws ServletException
GenericFilterBeanNote: This method will be called from standard filter initialization as well as filter bean initialization in a Spring application context. Filter name and ServletContext will be available in both cases.
This default implementation is empty.
initFilterBean in class GenericFilterBeanServletException - if subclass initialization failsGenericFilterBean.getFilterName(),
GenericFilterBean.getServletContext()
public void doFilter(ServletRequest request,
ServletResponse response,
FilterChain filterChain)
throws ServletException,
IOException
ServletException
IOExceptionpublic void destroy()
GenericFilterBeanNote: This method will be called from standard filter destruction as well as filter bean destruction in a Spring application context.
This default implementation is empty.
destroy in interface Filterdestroy in interface DisposableBeandestroy in class GenericFilterBeanprotected WebApplicationContext findWebApplicationContext()
WebApplicationContext passed in at construction time, if available.
Otherwise, attempt to retrieve a WebApplicationContext from the
ServletContext attribute with the configured name if set. Otherwise look up a WebApplicationContext under
the well-known "root" application context attribute. The
WebApplicationContext must have already been loaded and stored in the
ServletContext before this filter gets initialized (or invoked).
Subclasses may override this method to provide a different
WebApplicationContext retrieval strategy.
WebApplicationContext for this proxy, or null if not
foundDelegatingFilterProxy(String, WebApplicationContext),
getContextAttribute(),
WebApplicationContextUtils.getWebApplicationContext(javax.servlet.ServletContext),
WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE
protected Filter initDelegate(WebApplicationContext wac)
throws ServletException
The default implementation fetches the bean from the application context
and calls the standard Filter.init method on it, passing
in the FilterConfig of this Filter proxy.
wac - the root application context
ServletException - if thrown by the FiltergetTargetBeanName(),
isTargetFilterLifecycle(),
GenericFilterBean.getFilterConfig(),
Filter.init(javax.servlet.FilterConfig)
protected void invokeDelegate(Filter delegate,
ServletRequest request,
ServletResponse response,
FilterChain filterChain)
throws ServletException,
IOException
delegate - the delegate Filterrequest - the current HTTP requestresponse - the current HTTP responsefilterChain - the current FilterChain
ServletException - if thrown by the Filter
IOException - if thrown by the Filterprotected void destroyDelegate(Filter delegate)
Filter.destroy on it.
delegate - the Filter delegate (never null)isTargetFilterLifecycle(),
Filter.destroy()
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