When is servlet filter invoked

Show 12 more comments. Active Oldest Votes. Improve this answer. SparkOn SparkOn 8, 3 3 gold badges 24 24 silver badges 28 28 bronze badges. Right now I am trying to deploy this application on Websphere server.

It was working properly with this same configuration on Weblogic Server but on Websphere application it is giving problems. So my question is that does this behaviour differ for different application server? Add a comment. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password.

Post as a guest Name. Email Required, but never shown. The Overflow Blog. Podcast Explaining the semiconductor shortage, and how it might end. The FilterServletOutputStream class is used to manipulate the response of another resource. This class overrides the three write methods of the standard java.

OutputStream class. To use the custom ServletOutputStream class, implement a class that can act as a response object. This wrapper object is sent back to the client in place of the original response that was generated. The wrapper must implement some utility methods, such as to retrieve the content type and content length of its content. The GenericResponseWrapper class accomplishes this:. This filter adds content to the response after that target is invoked.

This filter extends the filter from "Generic Filter". Save this JSP code in filter3. You should see a page that looks something like what is shown in Figure The servlet specification includes the capability to track key events in your Web applications through event listeners. This functionality allows more efficient resource management and automated processing based on event status. The following sections describe servlet event listeners:.

This involves resources or state held at the level of the application servlet context object. This involves resources or state associated with the series of requests from a single user session; that is, associated with the HTTP session object. Attribute changes You can create one or more event listener classes for each of the four event categories.

A single listener class can monitor multiple event categories. Create an event listener class by implementing the appropriate interface or interfaces of the javax. Table summarizes the four categories and the associated interfaces.

Servlet context lifecycle changes Servlet context creation, at which point the first request can be serviced Imminent shutdown of the servlet context javax. ServletContextListener Servlet context attribute changes Addition of servlet context attributes Removal of servlet context attributes Replacement of servlet context attributes javax.

HttpSessionListener Session attribute changes Addition of session attributes Removal of session attributes Replacement of session attributes javax. A typical use of the event listener mechanism would be to create a servlet context lifecycle event listener to manage the database connection.

This listener might function as follows:. The application logs in to the database and stores the connection object in the servlet context.

Servlets use the database connection to perform SQL operations. The listener is notified of imminent application shutdown shutdown of the Web server or removal of the application from the Web server.

Prior to application shutdown, the listener closes the database connection. Event Listener Declaration and Invocation Event listeners are declared in the application web. Within each event category, event listeners should be specified in the order in which you would like them to be invoked when the application runs.

After the application starts up and before it services the first request, the servlet container creates and registers an instance of each listener class that you have declared. For each event category, listeners are registered in the order in which they are declared.

Then, as the application runs, event listeners for each category are invoked in the order of their registration. All listeners will remain active until after the last request is serviced for the application.

Upon application shutdown, session event listeners are notified first, in reverse order of their declarations, then application event listeners are notified in reverse order of their declarations. When the application runs, both listeners will be notified of servlet context lifecycle events, and the MyLoggingModule listener will also be notified of session lifecycle events.

For servlet context lifecycle events, the MyConnectionManager listener will be notified first, because of the declaration order. Each listener class must have a public zero-argument constructor. Note: In a distributed environment, the scope of event listeners is one for each deployment descriptor declaration for each JVM.

There is no requirement for distributed Web containers to propagate servlet context events or session events to additional JVMs. Event Listener Methods and Related Classes This section lists event listener methods that are called by the servlet container when a servlet context event or session event occurs. These methods take different types of event objects as input, so these event classes and their methods are also discussed. The servlet container calls this method to notify the listener that the servlet context has been created and the application is ready to process requests.

The servlet container calls this method to notify the listener that the application is about to be shut down. The servlet container creates a javax.

The ServletContextEvent class includes the following method, which your listener can call:. July 14, at am. Akhil says:. July 3, at am. Getnet says:. June 23, at am. Oleg says:. June 20, at am. June 14, at am. Abhishek says:. May 20, at pm. Jose Martinez says:. February 18, at am.

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Tutorials About RSS. Java Servlets. Servlet Filters. Here is an example servlet filter implementation: import javax. Tweet Jakob Jenkov.