Filters are like servlets. There exists many servlet container.Do filters take the role in servlet container only?

I read everytime Filters开发者_如何学C are like servlets. Resin is a servlet container. Is there exist any filter container to initialize filters or does it take the role in servlet container only. Can anybody elaborate how it works?

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• Servlets are components that handle an HTTP request/response cycle
• Filters are components that intercept HTTP requests and response before/after they reach the target servlet
• Servlet containers make sure the two points above work - i.e. they instantiate servlets and filters and "give" them the requests/responses

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There is nothing like Filter container, it is included in servlet container.

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Java Servlet Filters allow you to "layer on" additional behavior in front of a Servlet, JSP page, or even static resources like css, js, and image files.

The classic example of Filter use is Authorization: checking to ensure the user is authorized to view the specified resource.

Some observations:

• A Filter can do work before the specified resource (servlet, etc.), after, or both
• Multiple Filters may be applied to the same resource