filter过滤怎么使用 JSP - Java / Web 开发

SecurityFilter.java:文件

package tom;

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class SecurityFilter {

public void init(FilterConfig config) throws ServletException {}

  public void destroy() {}


public void doFilter(ServletRequest request,ServletResponse response,FilterChain chain)throws IOException, ServletException {

HttpServletRequest req = (HttpServletRequest) request;
HttpServletResponse res = (HttpServletResponse) response;
String uri=req.getRequestURI();
String ctx=req.getContextPath();
uri = uri.substring(ctx.length());
 
HttpSession session = req.getSession();
 
if (uri.startsWith("/admin")) {
if (session.getAttribute("admin") != null) {
chain.doFilter(request, response);
} else {
req.setAttribute("message", "您没有这个权限");
res.sendRedirect("../failure.jsp");
}
}
if(uri.startsWith("/manage")){
if(session.getAttribute("username") != null) {
chain.doFilter(request, response);

} else {
req.setAttribute("message","您没有这个权限"); 
req.getRequestDispatcher("/login.jsp").forwa