Explain Life cycle of Servlet Filter.

Question Posted / surajkumar.java

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Explain Life cycle of Servlet Filter...

Answer / sunita

filters life cycle:
The life cycle of a filter is managed by a container. Every
filter must implement the Filter interface. The life cycle
of a filter consists of implementing the following methods:

1. init(): This method is called only once after
instantiation to perform any initialization task.

2. doFilter(): This method is called after the init()
method. It takes three arguments, namely a ServletRequest, a
ServletResponse, and a FilterChain. It is called each time a
filter needs to perform any function. This method performs
the actual work of a filter, either modifying the request or
the response.

3. destroy(): This method is used to perform any cleanup
operation before the container removes a filter instance.

Is This Answer Correct ?

36 Yes

2 No

Explain Life cycle of Servlet Filter...

Answer / surajkumar.java

A java class which implements javax.servlet.Filter is
configured as filter in web.xml file.
The web container calls the init method to initialize filter
by passing javax.servlet.FilterConfig object to retrieve the
filter’s init parameters.
The doFilter method of Filter class performs the actual
processing like authentication, data format conversion and
page redirect to other page and catching etc. The doFilter
method passes the request and response object of the current
request and the filter chain object to invoke next filter in
the chain.
Web container calls the destroy() method to take the filter
out of service.

Is This Answer Correct ?

29 Yes

7 No

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