多选题Which the three are true about servlet filters？（）AA filter must implement the destroy methodBA filter must implement the doFilter methodCA servlet may have multiple filters associated with itDA servlet that is to have a filter applied to it must implem

A filter must implement the destroy method

A filter must implement the doFilter method

A servlet may have multiple filters associated with it

A servlet that is to have a filter applied to it must implement the javax.servlet.FilterChain  interface

A filter that is part of a filter chain passes control to the next filter in the chain by invoking the filterChain forward method

For each  element in the web application deployment descriptor， multiple instances of a filter may be created by the web container