Filter

类 implement Filter

public void init(FilterConfig filterConfig) throws ServletException {

}

    @Override

    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {

        filterChain.doFilter(servletRequest,servletResponse);

    }

    @Override

    public void destroy() {

    }

Filter顺序

注解按照命名顺序进行

xml 根据 mapping 顺序进行

注解写多个注解出发

urlPatterns={"/a","/b"}

HttpServletRequest request = (HttpServletRequest) ServletRequest;

//1.获取资源请求路径

String uri = request.getRequestURI();

创建和销毁

HttpSessionLister、ServletContextListener、ServletRequestListener

属性列表变化，分别为： HttpSessionAttributeLister、

 ServletContextAttributeListener、ServletRequestAttributeListener

Session ，分别为：

HttpSessionBindingListener 

               ( bound  和unbound事件)

                和

               HttpSessionActivationListener 钝化和激活的接口