Servlet的尾(yi)巴---filter ( 过滤器 )的小应用

 1 package Demo;
 2 
 3 import java.io.IOException;
 4 
 5 import javax.servlet.Filter;
 6 import javax.servlet.FilterChain;
 7 import javax.servlet.FilterConfig;
 8 import javax.servlet.ServletException;
 9 import javax.servlet.ServletRequest;
10 import javax.servlet.ServletResponse;
11 import javax.servlet.http.HttpServletRequest;
12 import javax.servlet.http.HttpServletResponse;
13 
14 public class Liuyanban implements Filter {
15 
16     @Override
17     public void destroy() {
18         // TODO Auto-generated method stub
19 
20     }
21 
22     @Override
23     public void doFilter(ServletRequest request, ServletResponse response,
24             FilterChain chain) throws IOException, ServletException {
25         // TODO Auto-generated method stub
26         
27         HttpServletRequest req = (HttpServletRequest)request ;
28         HttpServletResponse resp =(HttpServletResponse) response ;
29         String username = req.getParameter("username");
30         String comment = req.getParameter("comment");
31         username=username.replace("zhang","gong");
32         comment=comment.replace("animal","****");
33         req.setAttribute("username",username);
34         req.setAttribute("comment",comment);
35         chain.doFilter(request,response);
36 
37     }
38 
39     @Override
40     public void init(FilterConfig filterConfig) throws ServletException {
41         // TODO Auto-generated method stub
42 
43     }
44 
45 }