6 Java 内存马基础 ¶

    /**
 * Adds the filter with the given name and class name to this servlet context.
 *
 * <p>
 * The registered filter may be further configured via the returned {@link FilterRegistration} object.
 *
 * <p>
 * The specified <tt>className</tt> will be loaded using the classloader associated with the application represented by
 * this ServletContext.
 *
 * <p>
 * If this ServletContext already contains a preliminary FilterRegistration for a filter with the given
 * <tt>filterName</tt>, it will be completed (by assigning the given <tt>className</tt> to it) and returned.
 *
 * <p>
 * This method supports resource injection if the class with the given <tt>className</tt> represents a Managed Bean. See
 * the Jakarta EE platform and CDI specifications for additional details about Managed Beans and resource injection.
 *
 * @param filterName the name of the filter
 * @param className the fully qualified class name of the filter
 *
 * @return a FilterRegistration object that may be used to further configure the registered filter, or <tt>null</tt> if
 * this ServletContext already contains a complete FilterRegistration for a filter with the given <tt>filterName</tt>
 *
 * @throws IllegalStateException if this ServletContext has already been initialized
 *
 * @throws IllegalArgumentException if <code>filterName</code> is null or an empty String
 *
 * @throws UnsupportedOperationException if this ServletContext was passed to the
 * {@link ServletContextListener#contextInitialized} method of a {@link ServletContextListener} that was neither
 * declared in <code>web.xml</code> or <code>web-fragment.xml</code>, nor annotated with
 * {@link jakarta.servlet.annotation.WebListener}
 *
 * @since Servlet 3.0
 */
public FilterRegistration.Dynamic addFilter(String filterName, String className);

/**
 * Registers the given filter instance with this ServletContext under the given <tt>filterName</tt>.
 *
 * <p>
 * The registered filter may be further configured via the returned {@link FilterRegistration} object.
 *
 * <p>
 * If this ServletContext already contains a preliminary FilterRegistration for a filter with the given
 * <tt>filterName</tt>, it will be completed (by assigning the class name of the given filter instance to it) and
 * returned.
 *
 * @param filterName the name of the filter
 * @param filter the filter instance to register
 *
 * @return a FilterRegistration object that may be used to further configure the given filter, or <tt>null</tt> if this
 * ServletContext already contains a complete FilterRegistration for a filter with the given <tt>filterName</tt> or if
 * the same filter instance has already been registered with this or another ServletContext in the same container
 *
 * @throws IllegalStateException if this ServletContext has already been initialized
 *
 * @throws IllegalArgumentException if <code>filterName</code> is null or an empty String
 *
 * @throws UnsupportedOperationException if this ServletContext was passed to the
 * {@link ServletContextListener#contextInitialized} method of a {@link ServletContextListener} that was neither
 * declared in <code>web.xml</code> or <code>web-fragment.xml</code>, nor annotated with
 * {@link jakarta.servlet.annotation.WebListener}
 *
 * @since Servlet 3.0
 */
public FilterRegistration.Dynamic addFilter(String filterName, Filter filter);

    /**
     * Adds the filter with the given name and class type to this servlet context.
     *
     * <p>
     * The registered filter may be further configured via the returned {@link FilterRegistration} object.
     *
     * <p>
     * If this ServletContext already contains a preliminary FilterRegistration for a filter with the given
     * <tt>filterName</tt>, it will be completed (by assigning the name of the given <tt>filterClass</tt> to it) and
     * returned.
     *
     * <p>
     * This method supports resource injection if the given <tt>filterClass</tt> represents a Managed Bean. See the Jakarta
     * EE platform and CDI specifications for additional details about Managed Beans and resource injection.
     *
     * @param filterName the name of the filter
     * @param filterClass the class object from which the filter will be instantiated
     *
     * @return a FilterRegistration object that may be used to further configure the registered filter, or <tt>null</tt> if
     * this ServletContext already contains a complete FilterRegistration for a filter with the given <tt>filterName</tt>
     *
     * @throws IllegalStateException if this ServletContext has already been initialized
     *
     * @throws IllegalArgumentException if <code>filterName</code> is null or an empty String
     *
     * @throws UnsupportedOperationException if this ServletContext was passed to the
     * {@link ServletContextListener#contextInitialized} method of a {@link ServletContextListener} that was neither
     * declared in <code>web.xml</code> or <code>web-fragment.xml</code>, nor annotated with
     * {@link jakarta.servlet.annotation.WebListener}
     *
     * @since Servlet 3.0
     */
    public FilterRegistration.Dynamic addFilter(String filterName, Class<? extends Filter> filterClass);

    /**
     * Instantiates the given Filter class.
     *
     * <p>
     * The returned Filter instance may be further customized before it is registered with this ServletContext via a call to
     * {@link #addFilter(String,Filter)}.
     *
     * <p>
     * The given Filter class must define a zero argument constructor, which is used to instantiate it.
     *
     * <p>
     * This method supports resource injection if the given <tt>clazz</tt> represents a Managed Bean. See the Jakarta EE
     * platform and CDI specifications for additional details about Managed Beans and resource injection.
     *
     * @param <T> the class of the Filter to create
     * @param clazz the Filter class to instantiate
     *
     * @return the new Filter instance
     *
     * @throws ServletException if the given <tt>clazz</tt> fails to be instantiated
     *
     * @throws UnsupportedOperationException if this ServletContext was passed to the
     * {@link ServletContextListener#contextInitialized} method of a {@link ServletContextListener} that was neither
     * declared in <code>web.xml</code> or <code>web-fragment.xml</code>, nor annotated with
     * {@link jakarta.servlet.annotation.WebListener}
     *
     * @since Servlet 3.0
     */
    public <T extends Filter> T createFilter(Class<T> clazz) throws ServletException;