Filterservlet.java

 

package com.xxpx.servlet;

import java.io.IOException;

import javax.servlet.Filter;

import javax.servlet.FilterChain;

import javax.servlet.FilterConfig;

import javax.servlet.ServletException;

import javax.servlet.ServletRequest;

import javax.servlet.ServletResponse;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

import com.xxpx.bean.User;

public class FilterTest implements Filter{

    @Override

    public void destroy() {

        // TODO Auto-generated method stub

        

    }

    @Override

    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse,

            FilterChain arg2) throws IOException, ServletException {

        // TODO Auto-generated method stub

        HttpServletRequest request = (HttpServletRequest)servletRequest;

        String requestURI = request.getRequestURI();

        int lastIndexOf = requestURI.lastIndexOf("/");

        String substring = requestURI.substring(lastIndexOf+1);

        if("login.jsp".equals(substring)){

            arg2.doFilter(servletRequest, servletResponse);

        }else{

            HttpServletResponse response = (HttpServletResponse)servletResponse;

            HttpSession session = request.getSession();

            User user = (User)session.getAttribute("user");

            if(user==null){

                response.sendRedirect("login.jsp");

            }else{

                arg2.doFilter(servletRequest, servletResponse);

            }

        }

        

    }

    @Override

    public void init(FilterConfig arg0) throws ServletException {

        // TODO Auto-generated method stub

        System.out.println("开始过滤");

    }

}

web.xml配置

<filter>

   <filter-name>test</filter-name>

   <filter-class>com.xxpx.servlet.FilterTest</filter-class>

  </filter>

  <filter-mapping>

  <filter-name>test</filter-name>

  <url-pattern>/houtai/pages/*</url-pattern>

  <url-pattern>/houtai/main.jsp</url-pattern>

  </filter-mapping>