filter 过滤器 禁止浏览器缓存

 public class BrowserNoCacheFilter implements Filter {
     public void init(FilterConfig filterconfig) throws ServletException {
     }
     public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterchain) throws IOException, ServletException {
         ((HttpServletResponse) response).setHeader("Cache-Control", "no-cache");      //HTTP消息头，控制网页的缓存
         ((HttpServletResponse) response).setHeader("Pragma", "no-cache");        //禁止浏览器从缓存中调阅页面内容
         ((HttpServletResponse) response).setHeader("Expires", "-1");                   //指定网页在缓存中的过期时间
         filterchain.doFilter(request, response);
     }
     public void destroy() {
     }
 }