J2EE作业_拦截器

 1 @WebFilter(dispatcherTypes = {DispatcherType.REQUEST }
 2                     , urlPatterns = { "/*" })
 3 public class Filter1 implements Filter {
 4 
 5     public Filter1() {
 6     }
 7 
 8     public void destroy() {
 9     }
10 
11     public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
12         
13         HttpSession session=((HttpServletRequest)request).getSession();
14         boolean isAllowed=true;
15         if(session.getAttribute("user")==null){
16             if(!((HttpServletRequest)request).getServletPath().equals("/login.jsp"))
17                 isAllowed=false;
18         }
19         if(isAllowed)
20             chain.doFilter(request, response);
21         else
22             ((HttpServletResponse)response).sendRedirect("login.jsp");
23         
24     }
25 
26     public void init(FilterConfig fConfig) throws ServletException {
27     }
28 
29 }