Which three are true about servlet filters？（）
- AA filter must implement the destroy method.
- BA filter must implement the doFilter method.
- CA servlet may have multiple filters associated with it.
- DA servlet that is to have a filter applied to it must implement the javax.servlet.FilterChain interface.
- EA filter that is part of a filter chain passes control to the next filter in the chain by invoking the FilterChain.forward method.