Ch. 13 filters and wrappers
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This document discusses filters in Java web applications. Filters can intercept requests and responses and perform common functions like authentication, logging, image conversion, and localization. Filters are implemented using the Filter, FilterChain, and FilterConfig interfaces. Filters can be applied to servlets and JSP pages and are declared in deployment descriptors to define the order in which they execute. Examples of filters include security checks, response compression, and request tracking. Filters provide modular and reconfigurable functionality in web applications.
Ch. 13 filters and wrappers
- 1. Chapter 13 Filters and Wrappers Intercepting the requests & responses
- 2. Filters Provide universal functions that can be "attached" to any type of servlet or JSP page. • Authentication • Logging and auditing • Image conversion • Data compression • Localization • XSL/T transformations of XML content
- 3. Filters API Filter, FilterChain, and FilterConfig interfaces in the javax.servlet package. • Define a filter by implementing the Filter interface. • A filter chain, • passed to a filter by the container, • provides a mechanism for invoking a series of filters. • FilterConfig contains initialization data.
- 4. Filters • Security checks • Reformat headers and bodies • Audit/log • Compress • Append • Create new
- 5. Modular and Reconfigurable (in DD)
- 6. Filters are just like servlets • The Container knows their API • The Container manages their lifecycle • They are declared in DD
- 8. Stack
- 9. Declare and order (in DD)
- 12. API
- 15. Final Code
- 16. Compression Wrapper – helper class
- 17. Examples “Filter’s Essential” by Oracle