FilterChain usage

[Srinivasa Kadiyala]

I am usign a class that extends and implements doFilter() method.

I am getting an error some times. Is it necessary to add the following code ?

httpResponse.setHeader("Cache-Control", "no-cache");
httpResponse.setDateHeader("Expires", 0);
httpResponse.setHeader("Pragma", "No-cache");

Thanks in advance

[Srinivasa Kadiyala]

adding to my above subject...

I could not exactly get the idea and advantage of using Filter/ FilterChain.

Appreciate if any one can explain me also.

Thanks again in advance

[Jack Wiesenthaler]

perhaps you should be clear in explaining what it is you're trying to achieve and what kind of error you're getting ;-)

The purpose of a Servlet Filter is to intercept a Servlet request and possibly apply certain pre-processing logic modifying or blocking the response if you choose. One use can be auditing of requests (hit counters etc.), another use is in security to check if access to a resource can be granted for example checking to see if the user is logged in etc.

[Srinivasa Kadiyala]

Hi Kevin

The purpose is to use the filter for checking whether the user is logged-on to the website already or not.

Id already, he will navigate else log-on page is presented.

I am getting 500 error when doFilter(req,res) method of FilterChain is called.

Do not understand, why. Some times it works well. Some times gives 500 error.

Appreciate your feed back.

Thanks again...

[Yuriy Zilbergleyt]

500 Error means an exception was thrown. What is the exception and it's stack trace?

-Yuriy