Package org.springframework.web.filter

Class GenericFilterBean

java.lang.Object
org.springframework.web.filter.GenericFilterBean
All Implemented Interfaces:
Filter, Aware, BeanNameAware, DisposableBean, InitializingBean, EnvironmentAware, EnvironmentCapable, ServletContextAware
Direct Known Subclasses:
DelegatingFilterProxy, OncePerRequestFilter, ResourceUrlEncodingFilter
public abstract class GenericFilterBean extends Object implements Filter, BeanNameAware, EnvironmentAware, EnvironmentCapable, ServletContextAware, InitializingBean, DisposableBean
Simple base implementation of Filter which treats its config parameters (init-param entries within the filter tag in web.xml) as bean properties.

A handy superclass for any type of filter. Type conversion of config parameters is automatic, with the corresponding setter method getting invoked with the converted value. It is also possible for subclasses to specify required properties. Parameters without matching bean property setter will simply be ignored.

This filter leaves actual filtering to subclasses, which have to implement the Filter.doFilter(jakarta.servlet.ServletRequest, jakarta.servlet.ServletResponse, jakarta.servlet.FilterChain) method.

This generic filter base class has no dependency on the Spring ApplicationContext concept. Filters usually don't load their own context but rather access service beans from the Spring root application context, accessible via the filter's ServletContext (see WebApplicationContextUtils).

Since:
06.12.2003
Author:
Juergen Hoeller
See Also:

  • Field Details

    • logger

      protected final Log logger
      Logger available to subclasses.

  • Constructor Details

    • GenericFilterBean

      public GenericFilterBean()

  • Method Details

    • setBeanName

      public void setBeanName(String beanName)
      Stores the bean name as defined in the Spring bean factory.

      Only relevant in case of initialization as bean, to have a name as fallback to the filter name usually provided by a FilterConfig instance.

      Specified by:
      setBeanName in interface BeanNameAware
      Parameters:
      beanName - the name of the bean in the factory. Note that this name is the actual bean name used in the factory, which may differ from the originally specified name: in particular for inner bean names, the actual bean name might have been made unique through appending "#..." suffixes. Use the BeanFactoryUtils.originalBeanName(String) method to extract the original bean name (without suffix), if desired.
      See Also:

    • setEnvironment

      public void setEnvironment(Environment environment)
      Set the Environment that this filter runs in.

      Any environment set here overrides the StandardServletEnvironment provided by default.

      This Environment object is used only for resolving placeholders in resource paths passed into init-parameters for this filter. If no init-params are used, this Environment can be essentially ignored.

      Specified by:
      setEnvironment in interface EnvironmentAware

    • getEnvironment

      public Environment getEnvironment()
      Return the Environment associated with this filter.

      If none specified, a default environment will be initialized via createEnvironment().

      Specified by:
      getEnvironment in interface EnvironmentCapable
      Since:
      4.3.9

    • createEnvironment

      protected Environment createEnvironment()
      Create and return a new StandardServletEnvironment.

      Subclasses may override this in order to configure the environment or specialize the environment type returned.

      Since:
      4.3.9

    • setServletContext

      public void setServletContext(ServletContext servletContext)
      Stores the ServletContext that the bean factory runs in.

      Only relevant in case of initialization as bean, to have a ServletContext as fallback to the context usually provided by a FilterConfig instance.

      Specified by:
      setServletContext in interface ServletContextAware
      Parameters:
      servletContext - the ServletContext object to be used by this object
      See Also:

    • afterPropertiesSet

      public void afterPropertiesSet() throws ServletException
      Calls the initFilterBean() method that might contain custom initialization of a subclass.

      Only relevant in case of initialization as bean, where the standard init(FilterConfig) method won't be called.

      Specified by:
      afterPropertiesSet in interface InitializingBean
      Throws:
      ServletException
      See Also:

    • destroy

      public void destroy()
      Subclasses may override this to perform custom filter shutdown.

      Note: 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.

      Specified by:
      destroy in interface DisposableBean
      Specified by:
      destroy in interface Filter

    • addRequiredProperty

      protected final void addRequiredProperty(String property)
      Subclasses can invoke this method to specify that this property (which must match a JavaBean property they expose) is mandatory, and must be supplied as a config parameter. This should be called from the constructor of a subclass.

      This method is only relevant in case of traditional initialization driven by a FilterConfig instance.

      Parameters:
      property - name of the required property

    • init

      public final void init(FilterConfig filterConfig) throws ServletException
      Standard way of initializing this filter. Map config parameters onto bean properties of this filter, and invoke subclass initialization.
      Specified by:
      init in interface Filter
      Parameters:
      filterConfig - the configuration for this filter
      Throws:
      ServletException - if bean properties are invalid (or required properties are missing), or if subclass initialization fails.
      See Also:

    • initBeanWrapper

      protected void initBeanWrapper(BeanWrapper bw) throws BeansException
      Initialize the BeanWrapper for this GenericFilterBean, possibly with custom editors.

      This default implementation is empty.

      Parameters:
      bw - the BeanWrapper to initialize
      Throws:
      BeansException - if thrown by BeanWrapper methods
      See Also:

    • initFilterBean

      protected void initFilterBean() throws ServletException
      Subclasses may override this to perform custom initialization. All bean properties of this filter will have been set before this method is invoked.

      Note: 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.

      Throws:
      ServletException - if subclass initialization fails
      See Also:

    • getFilterConfig

      @Nullable public FilterConfig getFilterConfig()
      Make the FilterConfig of this filter available, if any. Analogous to GenericServlet's getServletConfig().

      Public to resemble the getFilterConfig() method of the Servlet Filter version that shipped with WebLogic 6.1.

      Returns:
      the FilterConfig instance, or null if none available
      See Also:

    • getFilterName

      @Nullable protected String getFilterName()
      Make the name of this filter available to subclasses. Analogous to GenericServlet's getServletName().

      Takes the FilterConfig's filter name by default. If initialized as bean in a Spring application context, it falls back to the bean name as defined in the bean factory.

      Returns:
      the filter name, or null if none available
      See Also:

    • getServletContext

      protected ServletContext getServletContext()
      Make the ServletContext of this filter available to subclasses. Analogous to GenericServlet's getServletContext().

      Takes the FilterConfig's ServletContext by default. If initialized as bean in a Spring application context, it falls back to the ServletContext that the bean factory runs in.

      Returns:
      the ServletContext instance
      Throws:
      IllegalStateException - if no ServletContext is available
      See Also: