Filters are used to process requests and responses in servlets. Filters intercept requests before they reach servlets and responses after they leave servlets. This allows filters to perform functions like authentication, logging, compression, and more across multiple servlets. To create a filter, we implement the Filter interface and define init(), doFilter(), and destroy() methods. The doFilter() method contains the main filtering logic and can pass the request and response to the next filter or servlet in the chain. Filters are configured in web.xml and can be chained to customize request and response processing.

1. What are Servlet Filters ? Discuss about customization of request and response using filtersFilters are used to process the content in the request or response objects of Servlets and generally they do not produce the responses. Filters interrupt

2. Requestsbefore the servlet was processed

3. Response immediately after the request was processed or before the response sent to the client Enhances the lifecycle process

4. Used to perform various functions across the multiple servlets in a Web application To add features to existing servlet code

5. Also create reusable functions to use in multiple Web applicationsWhat are Servlet Filters ?Example Customize the authentication process using filter

6. Filter intercepts the request - check whether the sufficient permission was given to the user to access the requested servlet Prevent the unauthorized user from accessing the servlet Used to record

7. User actions

8. Compress the output streams

9. Very flexible because we won’t write the filters within servlets

10. Configured in the web.xmlWhat are Servlet Filters ?Implementation of FilterRequestRequestResponseResponseClientSampleFilter.javaSample Servlet.javaFilterServlet