创建一个过滤器拦截所有请求
项目结构: AFilter: package cn.itcast.web.filter; import javax.servlet.*; import java.io.IOException; public class AFilter implements Filter { /** * init方法在filter创建之后立即执行,用来做初始化 * @param filterConfig * @throws ServletException */ @Override public void init(FilterConfig filterConfig) throws ServletException { System.out.println("过滤器初始化!"); } /** * 每次过滤时都会执行 * @param servletRequest * @param servletResponse * @param filterChain * @throws IOException * @throws ServletException */ @Override public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain)