The doFilter method of the Filter is called by the
container each time a request/response pair is passed through the
chain due to a client request for a resource at the end of the chain.
The FilterChain passed in to this method allows the Filter to pass
on the request and response to the next entity in the chain.
A typical implementation of this method would follow the following
Examine the request
Optionally wrap the request object with a custom implementation to
filter content or headers for input filtering
Optionally wrap the response object with a custom implementation to
filter content or headers for output filtering
Either invoke the next entity in the chain
using the FilterChain object
or not pass on the request/response pair to
the next entity in the filter chain to
block the request processing
Directly set headers on the response after invocation of the
next entity in the filter chain.
request - the ServletRequest object contains the client's request
response - the ServletResponse object contains the filter's response
filterChain - the FilterChain for invoking the next filter or the resource
java.io.IOException - if an I/O related error has occurred during the processing
ServletException - if an exception occurs that interferes with the
filter's normal operation